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>> Narrator: NASA's Jet
 Propulsion Laboratory presents

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the von Kármán Lecture,

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a series of talks by
  scientists and engineers,

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who are exploring our
  planet, our solar system,

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and all that lies beyond.

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[uplifting music]

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>> Hey, good evening,
 ladies and gentlemen.

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How's everyone tonight?

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Good, thanks for coming
out to join us on

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this really toasty evening.

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So, the Spitzer Space Telescope

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is one of NASA's
 great observatories,

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and was designed to observe
the universe in infrared light.

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Launched in 2003, with an
expected lifetime of five years,

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the scope is still making
  amazing discoveries

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in its 15th year of operations.

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Tonight, our guest will discuss

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some of the novel
  engineering feats

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that have been made to extend
 the operation of Spitzer,

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as well as some of the
 technical challenges

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that the team is now facing.

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We'll also see some
  recent science highlights,

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including science that Spitzer
 was never designed to do.

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Tonight's guest received
his PhD in astronomy

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from Rensselaer Polytechnic
 Institute in 1995.

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Prior to arriving
 at Caltech in 2002,

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he worked at Boston College,

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and the Air Force
 Research Laboratory,

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helping to produce
  an infrared survey

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of the galactic plane
with the MSX satellite.

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At Caltech, he has worked
  at IPAC in various roles

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at the Spitzer Science Center,

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including leading the
instrument support team

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for the infrared array
 camera on Spitzer,

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before becoming the manager of
 the science center, in 2016.

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He has diverse research
 interests, from exoplanets,

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to massive star formation,
  to mere Earth asteroids.

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He enjoys the challenges of

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calibrating infrared
 instruments,

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and he likes to give data
  away to the community

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in the form of large surveys
 of the plane of our galaxy.

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Ladies and gentlemen,
 please help me welcome

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tonight's guest,
Dr. Shawn Carey.

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[audience applauds]

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>> Thank you, thank you.

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Thank you, everyone.

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It's my privilege to
 talk to you tonight,

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about the Spitzer
  Space Telescope,

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which is an amazing instrument,

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which many of you
 may never heard of.

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I hope all of you
 have heard about the

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Hubble Space Telescope,
 may I see a raise of hands,

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how many people have
 heard of Hubble?

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Okay, pretty good.

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How about Spitzer, how many
 of you heard of Spitzer?

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Oh, that's awesome,
 actually, that's fantastic,

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so talking to my people here.

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It's a little bit humbling,

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because Spitzer's been
operating for 15 years,

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and there's an amazing breadth
 and depth to the discoveries.

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So I'm not gonna be
able to cover all that,

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nor am I gonna be
 able to cover all the

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excellent engineering that
 went into building Spitzer,

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getting it launched, and then
 continuing to operate it,

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for as long as we can.

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So, I'm gonna kind
  of pick the things

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that I think are
  interesting, pretty much.

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So, as you know in these days,

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you have to understand where
your information's coming from.

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What the source of
 the information is,

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and what their biases are.

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So I'm gonna try to tell
  you about my biases, okay?

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First thing is, since we've
 been in operation so long,

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I've kind of forgotten
 what happened

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before the cryogen ran out.

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So most of the stuff
I'm gonna tell you about

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is the new stuff.

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What we did in the post
 cryogenic role for Spitzer,

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when all the helium
 ran out of the tank.

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And I'll explain why
 that's important.

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Part of that, too, is
  because all of that data,

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is focused on the
 instrument that I worked on,

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which was the
 infrared ray camera,

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which half of that
 is still operating,

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and we'll talk a little
bit more about that.

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And then as far
  as research goes,

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I don't know very much
 about black holes,

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the high redshift universe,
 galaxies in general,

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so you're not gonna hear
a whole lot about that,

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so if you're interested
in that, I'm sorry.

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I know there's some
 other good talks

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in the von Kármán Lecture
  series that discuss those,

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and if there's any of my
 colleagues in the audience,

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whom that's the
 research interest,

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you can bother
me later.

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I'm sorry, but I don't feel
comfortable talking about that.

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What I am comfortable talking
 about, is images like this.

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So this is an image of
the plane of our galaxy,

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so this is a little
 bit of the Milky Way.

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And it's seen in the infrared,

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and in the images I show,
 the way we're gonna map it,

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is we usually have
three different

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colors, or wavelengths.

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And the blue is, the shortest
 wavelength will be blue,

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the middle one will be green,

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and then the longest
wavelength will be red.

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So you can see, there's
 things that are blue in here,

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and those are the
 objects that emitted

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the shortest wavelength,
those are stars.

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And then you see a lot
 of stuff that's green,

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which is gas and dust.

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That's a pretty common theme
 of what's done with Spitzer.

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And then there's some red spots
too, which are gas and dust

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and some other
 things of interest.

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Okay, and this
  image actually has

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my favorite object ever in it,

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something I've been
  studying for a long time,

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since 1998, which is this...

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Here, let's see, I
 can point it out...

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This snake like shape
 that's very dark,

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and it's very dark
  in the infrared,

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and we called it The Snake
 when we first discovered it,

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in my previous existence,
working with the MSX satellite.

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Which did a survey.

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Oh, see, running
 out of battery here.

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Okay, anyways.

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You can see the snake.

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That object there, is blocking

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not just visible light,
but infrared light,

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and that tells us
  it's very dense,

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and there's a lot
  of material there,

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'cause that's the only
 way you're blocking

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the background infrared light.

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And because of that,
  there's a lot of material,

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it's cold material,
 if it wasn't cold,

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it would be emitting
 in the infrared.

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This is something where,
 place where stars are forming,

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and we knew about that
but with the MSX stuff,

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we didn't have the
 beautiful resolution,

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the very clear
 picture from Spitzer,

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and we didn't see
 the little red dots,

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can everybody see the little
 red dots in the dark plane?

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Those are objects that are
formed, they're becoming stars.

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Those are what we call
  protostars, or baby stars.

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So they haven't
 gotten to the point

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where they have nuclear fusion,

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and have lit up and are
  glowing and are very hot,

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but they're on their way,

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they're gravitationally
collapsing,

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and so they're sort
 of hottish, warmish,

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and they're emitting
 in the infrared.

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Anyways, this is one of
my favorite pictures.

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The other reason it's one
  of my favorite pictures,

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is it shows the whole life cycle

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of star formation,
 from the dark stuff,

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which is material stars could
 potentially form out of.

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So the red little dots,
which are parts of

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that stuff that are
 gravitationally collapsing,

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and are on their way
 to forming stars,

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to all the blue dots, okay,
 all the little blue specs,

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those are stars.

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Okay, there's a lot of
 stars in this image.

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To this bright, red object ...

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Good, I got it back.

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Just have to press hard.

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Down here, that blob
 there, actually,

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is the remains of what happens

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when a massive star explodes,
 this is a supernova remnant,

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and what you're seeing is
 the hot gas that's left over,

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after the star
 exploded and heated up

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the material around it.

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So we go all the way from
  possibly forming stars,

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to forming stars,
  to actual stars,

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to the death of a
star, all in one image.

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Okay.

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But, before we get
 more into the science,

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why do you care
 about the infrared?

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I mean, why not just build
 more Hubble Space Telescopes?

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Well, the reason is,
 the infrared gives us

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an entirely different
picture of the universe,

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than what we can see
 in visible light.

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Here's a friend of mine,
and a former colleague,

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Jim Keller, and you can see
 him in the visible light.

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Looking quite dapper.

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And then this is Jim
 in the infrared light.

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Taken with a camera that you
 could put on your iPhone now,

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or one of the floor cameras
 that the firefighters use.

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And you can see
 quite a difference,

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in what you can see
 and not see, right?

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Jim's hands, he's
  wearing a trash bag here,

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he doesn't usually do that,

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but he's doing it
  for this purpose,

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because in visible light,
  you can't see his hands,

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but the trash bag, the plastic,

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is transparent in
 the infrared light.

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So the infrared light
  will pass through objects

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that are absorbing
  visible light,

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and that's kind
  of a common theme,

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you should go to longer
and longer wavelengths.

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The material in our galaxy,
all the material between stars,

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the interstellar medium, will
 absorb shorter wavelengths,

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like visible light first, and
 the infrared light, less so.

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So it's longer the
 wavelength it goes,

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the more you can see
  through things in general,

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but not quite, right?

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Because his glasses...
 you can't see in the infrared,

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the glass actually blocks
  the infrared light.

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And the other thing you notice,

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is that, in the visible light,

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what we're seeing is
 the light reflected

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off of Jim from an
  external source.

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In the infrared, you can
actually see the glow from him,

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it's his body heat that's
emitting the infrared radiation.

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So, the infrared light
allows us to see things

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that are cooler than
 emit visible light.

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So, that's what I
  was saying here,

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objects colder than stars
 that give off infrared light.

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So here's an object,

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this is another thing,
 called a Bok globule.

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It's kind of like those
infrared dark clouds

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that I talked about, in
 this you see invisible light

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and you can't really
 see through it,

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there's a couple
little red dots,

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which are stars on the edge.

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Where the material's
 not as thick,

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that you can see sort
 of poking through.

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Then if you look at
 the infrared light,

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you get an entirely
 different picture.

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So I'm just gonna flip back
 and forth for a second,

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so you can see that.

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And one of the things you'll
 notice is there's this

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bright blob, bright thing
  there, that's a star.

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That's a cool object, it's
 not a star, it's a protostar,

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it's something on the
 way to forming a star,

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so you wouldn't see it
 in the visible light,

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even if it was
 right on the surface

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of the globule that
 it's forming out of.

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The only thing you see
there is a little blob,

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which is a protostellar jet.

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So this material here, coming
 either way from the star,

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is what we call a
 protostellar outflow.

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Basically, what happens
 when something's collapsing

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to form a star, it collapses
 and forms a disc, a pancake,

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and the material
from the pancake

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infalls to a central object.

246
00:09:47,319 --> 00:09:49,588
And then when the
  material infalls,

247
00:09:49,621 --> 00:09:51,957
some of it gets pushed
 out, in an outflow,

248
00:09:51,990 --> 00:09:53,359
and that's what
 you're seeing there,

249
00:09:53,392 --> 00:09:57,630
along the line, is
  that's gas being ejected.

250
00:09:57,663 --> 00:09:59,565
Part of, some of the
 inflowing material

251
00:09:59,598 --> 00:10:02,668
being back ejected out from
 the star that's forming.

252
00:10:04,036 --> 00:10:07,206
So, things that give off
 infrared light that are colder

253
00:10:07,239 --> 00:10:09,775
than things we see in the
 visible light, are protostars.

254
00:10:09,808 --> 00:10:11,276
Planets also, if
 they're warm enough,

255
00:10:11,309 --> 00:10:13,612
will emit in the infrared,
  and we can actually see

256
00:10:13,645 --> 00:10:15,614
the emission of the
planets in the infrared.

257
00:10:15,647 --> 00:10:17,716
And then, in our solar
 system we can see

258
00:10:17,749 --> 00:10:21,920
asteroids and comets in
the reflected sunlight,

259
00:10:21,953 --> 00:10:24,890
but we can also see
 them much more easily

260
00:10:24,923 --> 00:10:26,625
in their own infrared radiation,

261
00:10:26,658 --> 00:10:28,193
provided that
 they're hot enough,

262
00:10:28,226 --> 00:10:31,163
so as comets come
  in and heat up,

263
00:10:31,196 --> 00:10:33,899
you'll pick them up very
easily in the infrared.

264
00:10:37,602 --> 00:10:39,605
The other thing, which we talked
a little bit about already,

265
00:10:39,638 --> 00:10:41,674
I just want to give another
 example is it's easier

266
00:10:41,707 --> 00:10:44,410
to see through the dust
  that's between the stars,

267
00:10:44,443 --> 00:10:45,644
and when I talk about dust here,

268
00:10:45,677 --> 00:10:48,947
it's not like dirt sized dust,

269
00:10:48,980 --> 00:10:50,783
this is more like cosmic soot,

270
00:10:50,816 --> 00:10:52,551
so it's not like the dust
  bunnies under your bed,

271
00:10:52,584 --> 00:10:54,520
it's more like auto
 exhaust, actually.

272
00:10:54,553 --> 00:10:56,622
Or smog, is a good example.

273
00:10:56,655 --> 00:10:58,323
And that actually blocks
out visible light,

274
00:10:58,356 --> 00:11:00,592
as you could tell
looking at the mountains

275
00:11:00,625 --> 00:11:04,597
on your way here, right, if
you were coming from the south.

276
00:11:06,064 --> 00:11:08,333
In the infrared, that light
 passes more readily through,

277
00:11:08,366 --> 00:11:11,036
because it's a longer wavelength
and you can see that here,

278
00:11:11,069 --> 00:11:13,338
in an image of the
 North American Nebula,

279
00:11:13,371 --> 00:11:15,207
where there's this dark
dust lane, in between,

280
00:11:15,240 --> 00:11:16,375
you can see sort of the shape

281
00:11:16,408 --> 00:11:18,844
of the North
 America here, right.

282
00:11:18,877 --> 00:11:22,848
There's the outline, there's
 Mexico, maybe Florida there.

283
00:11:22,881 --> 00:11:25,884
It takes a little imagination
 to come up with these names

284
00:11:25,917 --> 00:11:28,220
but then, there's this
 dark lane here, right,

285
00:11:28,253 --> 00:11:32,157
and that dark lane, with some
 foreground stars, is lit up,

286
00:11:32,190 --> 00:11:35,461
in the infrared light, what
you're seeing there is the gap,

287
00:11:35,494 --> 00:11:38,630
the dust and gas
  that is obscuring,

288
00:11:38,663 --> 00:11:42,234
the invisible light from behind,
is glowing in the infrared.

289
00:11:42,267 --> 00:11:46,505
so we get to understand about
 the material in between stars,

290
00:11:46,538 --> 00:11:48,140
by looking at infrared light.

291
00:11:49,641 --> 00:11:51,610
And then the other thing
  that's really interesting,

292
00:11:51,643 --> 00:11:54,179
is it allows us to see objects

293
00:11:54,212 --> 00:11:56,215
more easily that are in
  the early universe, okay,

294
00:11:56,248 --> 00:11:58,784
and this takes a little
  bit of effort, because...

295
00:11:58,817 --> 00:12:00,085
What's happening here...

296
00:12:00,118 --> 00:12:02,187
So, the foreground
 stuff, all the things

297
00:12:02,220 --> 00:12:05,090
that are greenish-blue
 are stars.

298
00:12:05,123 --> 00:12:07,693
The little red dots
are background galaxies

299
00:12:07,726 --> 00:12:10,062
that are fairly
  far away from us,

300
00:12:10,095 --> 00:12:12,397
and so we're seeing
 light that was emitted

301
00:12:12,430 --> 00:12:16,235
from some time in
  the past, right,

302
00:12:16,268 --> 00:12:18,437
because the light takes
time to travel to us,

303
00:12:18,470 --> 00:12:19,838
the farther away something is,

304
00:12:19,871 --> 00:12:21,907
the longer the light
 takes to travel to us,

305
00:12:21,940 --> 00:12:24,076
and since the
 universe is expanding,

306
00:12:24,109 --> 00:12:26,378
as the light's traveling to us,

307
00:12:26,411 --> 00:12:29,314
the distance that it
 travels gets larger.

308
00:12:29,347 --> 00:12:33,252
So as space is expanding,
  and when it does that,

309
00:12:33,285 --> 00:12:34,853
it has the property
 of making the light

310
00:12:34,886 --> 00:12:36,722
as it travels through
 and we see it,

311
00:12:36,755 --> 00:12:39,057
go to longer and longer
wavelengths, meaning basically,

312
00:12:39,090 --> 00:12:41,093
the material it's
 travelling through,

313
00:12:41,126 --> 00:12:44,129
is stretched out, so the
  light gets stretched out.

314
00:12:44,162 --> 00:12:48,100
So, as you look further
  and further back in time,

315
00:12:48,133 --> 00:12:51,303
something emits invisible
 light will look progressively

316
00:12:51,336 --> 00:12:53,172
redder and redder.

317
00:12:53,205 --> 00:12:55,274
That's, when you heard
 the term redshift,

318
00:12:55,307 --> 00:12:56,608
that's actually, that's
what we mean by that,

319
00:12:56,641 --> 00:12:59,178
is that the light is
actually getting redder,

320
00:12:59,211 --> 00:13:01,981
the further you look
 back in the universe.

321
00:13:03,281 --> 00:13:04,883
Which is just what
 I was saying there.

322
00:13:04,916 --> 00:13:06,218
Okay.
  So that's very important.

323
00:13:06,251 --> 00:13:08,720
If you're interested in studying

324
00:13:08,753 --> 00:13:10,422
the early universe,
 which I have to admit,

325
00:13:10,455 --> 00:13:13,525
I'm not super interested in,
 but I think it's pretty cool,

326
00:13:13,558 --> 00:13:15,060
then you want to use the
infrared light

327
00:13:15,093 --> 00:13:16,529
to do that as well.

328
00:13:17,629 --> 00:13:19,231
Okay, so that brings
 us to Spitzer.

329
00:13:19,264 --> 00:13:23,435
Okay, Spitzer is an
 infrared observatory,

330
00:13:23,468 --> 00:13:26,572
that is used by astronomers
 all over the world,

331
00:13:26,605 --> 00:13:28,540
anybody in the
  world can propose,

332
00:13:28,573 --> 00:13:31,243
if you wanted to write a
 proposal to use Spitzer time,

333
00:13:31,276 --> 00:13:34,580
you could do that,
 anybody, any country,

334
00:13:34,613 --> 00:13:35,814
you don't have to have a degree,

335
00:13:35,847 --> 00:13:37,349
you just have to
  have a good idea,

336
00:13:37,382 --> 00:13:40,118
and get it past the people who
 review the ideas to make sure

337
00:13:40,151 --> 00:13:42,921
one, it's a really good science
idea, so it should be done,

338
00:13:42,954 --> 00:13:45,757
and two, we can actually
 take the data that you need

339
00:13:45,790 --> 00:13:47,559
to get your science idea done.

340
00:13:47,592 --> 00:13:50,829
So, Spitzer launched
 August 25th, 2003,

341
00:13:50,862 --> 00:13:53,031
which seems like a
lifetime ago to me now,

342
00:13:53,064 --> 00:13:54,166
but it wasn't that long ago.

343
00:13:54,199 --> 00:13:55,601
It was very exciting.

344
00:13:55,634 --> 00:13:57,603
Here's Spitzer on
  the Delta Heavy

345
00:13:57,636 --> 00:14:00,138
that it was launched
from at Cape Canaveral.

346
00:14:00,171 --> 00:14:02,107
We had a few launch
 delays before that,

347
00:14:02,140 --> 00:14:04,142
so everybody that was
  working on the project was

348
00:14:04,175 --> 00:14:07,746
really anxious for it to get
 launched and us to get going.

349
00:14:07,779 --> 00:14:10,883
It was the last of NASA's
  Great Observatory program.

350
00:14:12,317 --> 00:14:16,822
Which included the Compton
  Gamma Ray Satellite,

351
00:14:16,855 --> 00:14:18,857
the Hubble Space Telescope,
 which you've all heard of,

352
00:14:18,890 --> 00:14:20,692
and the Chandra X-ray Telescope.

353
00:14:20,725 --> 00:14:22,828
So three of those four
 great observatories

354
00:14:22,861 --> 00:14:25,430
are still operating,
  giving us wonderful data,

355
00:14:25,463 --> 00:14:28,033
which spans a whole
 range of wavelengths

356
00:14:28,066 --> 00:14:30,168
that astronomers are
 really interested in,

357
00:14:30,201 --> 00:14:34,172
and the synergy between those
 three observatories is huge.

358
00:14:34,205 --> 00:14:36,642
A lot of times, we
 will take Spitzer data

359
00:14:36,675 --> 00:14:38,310
because Hubble has
 discovered something.

360
00:14:38,343 --> 00:14:40,145
Or somebody will see
  something in Spitzer data,

361
00:14:40,178 --> 00:14:42,915
and do a follow up with
 the Chandra X-ray Telescope

362
00:14:42,948 --> 00:14:44,316
to get more information.

363
00:14:45,884 --> 00:14:49,321
Spitzer's expected lifetime
 was five years, and ...

364
00:14:49,354 --> 00:14:51,723
[phone ringtone]

365
00:14:51,756 --> 00:14:53,559
I'll just wait for
  somebody to mute.

366
00:14:54,726 --> 00:14:56,462
It's okay, I do that
 all the time, too.

367
00:14:57,562 --> 00:14:59,298
Its expected lifetime
 was five years,

368
00:14:59,331 --> 00:15:03,101
that's how much helium
 we had in the tank,

369
00:15:03,134 --> 00:15:04,636
or what we thought it was.

370
00:15:04,669 --> 00:15:07,506
And the lifetime, if it only
 lasted two and a half years,

371
00:15:07,539 --> 00:15:08,941
we would've met
  our mission goal,

372
00:15:08,974 --> 00:15:10,208
so we would've been happy
  with two and a half.

373
00:15:10,241 --> 00:15:12,244
We were ecstatic with five.

374
00:15:12,277 --> 00:15:13,879
It ended up the
  cryogenic mission,

375
00:15:13,912 --> 00:15:16,448
so when we ran out of the
  coolant that we needed,

376
00:15:16,481 --> 00:15:19,051
ended 15 May, 2009,
 so we even got more

377
00:15:19,084 --> 00:15:20,485
than the five years' we planned,

378
00:15:20,518 --> 00:15:23,588
because people were really
smart in how we use the helium,

379
00:15:23,621 --> 00:15:25,357
because we actually had
some control over that,

380
00:15:25,390 --> 00:15:27,025
which I'll talk
  about in a second.

381
00:15:27,058 --> 00:15:30,362
And then after we ran
 out of the cryogen,

382
00:15:30,395 --> 00:15:34,599
we started the warm mission
 science in July, 2009,

383
00:15:34,632 --> 00:15:37,569
and we're still going,
 which is fantastic.

384
00:15:37,602 --> 00:15:38,904
It's fantastic for
  a lot of reasons,

385
00:15:38,937 --> 00:15:40,305
one, the spacecraft
 still working.

386
00:15:40,338 --> 00:15:41,506
[knocking]

387
00:15:41,539 --> 00:15:43,008
Knock on wood every
 time I say that,

388
00:15:43,041 --> 00:15:46,411
because my phone may go off
 and that would be a bad thing,

389
00:15:46,444 --> 00:15:47,879
because that would tell
us there's an anomaly,

390
00:15:47,912 --> 00:15:49,114
and if there's a bunch of people

391
00:15:49,147 --> 00:15:50,816
in the audience, that
 I know, got up too,

392
00:15:50,849 --> 00:15:53,919
we would know it's a really
 big deal, but so far, so good.

393
00:15:53,952 --> 00:15:55,187
So I haven't jinxed us.

394
00:15:56,955 --> 00:15:59,124
And the science still
 is excellent, in fact,

395
00:15:59,157 --> 00:16:01,493
the science now, I would
argue in some ways,

396
00:16:01,526 --> 00:16:03,462
is better, because
  people's ideas are better,

397
00:16:03,495 --> 00:16:06,431
because we're learning
 more every year,

398
00:16:06,464 --> 00:16:08,000
about the universe.

399
00:16:10,301 --> 00:16:11,870
Let's see, what did
 I not do right here?

400
00:16:11,903 --> 00:16:13,939
Okay, so ...

401
00:16:13,972 --> 00:16:15,874
The Spitzer Space
  Telescope was named after

402
00:16:15,907 --> 00:16:18,377
a very prominent astronomer
 named Lyman Spitzer,

403
00:16:18,410 --> 00:16:19,878
here's a picture
  of Lyman Spitzer,

404
00:16:19,911 --> 00:16:22,581
he was also an avid mountain
 climber, and this is him,

405
00:16:22,614 --> 00:16:25,350
Lyman, on his way to
climbing the Matterhorn.

406
00:16:25,383 --> 00:16:28,587
And this is... and the
 way Spitzer was named,

407
00:16:28,620 --> 00:16:30,922
is we had a contest, actually,

408
00:16:30,955 --> 00:16:33,625
and people wrote in
 whom they thought,

409
00:16:33,658 --> 00:16:36,261
what the name for the
 telescope should be,

410
00:16:36,294 --> 00:16:39,197
because the idea usually,
  or back in the past was,

411
00:16:39,230 --> 00:16:41,733
you didn't name an
 observatory that was launched

412
00:16:41,766 --> 00:16:44,169
into space until it was
actually operational.

413
00:16:44,202 --> 00:16:47,272
Before Spitzer was operational,
it was called SIRTF,

414
00:16:47,305 --> 00:16:49,841
which was an acronym for
a popular NASA thing,

415
00:16:49,874 --> 00:16:54,480
which stood for Space
 Infrared Telescope Facility,

416
00:16:55,380 --> 00:16:56,515
really exciting, right?

417
00:16:57,916 --> 00:17:00,052
Before it was the Space
 Infrared Telescope Facility,

418
00:17:00,085 --> 00:17:01,586
and a form incarnation,

419
00:17:01,619 --> 00:17:03,789
it was actually the Shuttle
 Infrared Telescope Facility,

420
00:17:03,822 --> 00:17:05,424
the idea was that
 was gonna be launched

421
00:17:05,457 --> 00:17:07,159
on the shuttle like Hubble.

422
00:17:07,192 --> 00:17:09,928
It ended up by the time that
 it was getting developed,

423
00:17:09,961 --> 00:17:12,330
in the 90s, that got
really expensive to do,

424
00:17:12,363 --> 00:17:14,132
and people had a much
better way of doing it,

425
00:17:14,165 --> 00:17:15,734
so instead of putting
 it on the shuttle

426
00:17:15,767 --> 00:17:18,970
and lifting it up,
 like Hubble was done,

427
00:17:19,003 --> 00:17:21,339
and then the idea then was
 you were gonna periodically

428
00:17:21,372 --> 00:17:24,142
send up the shuttle and top
 off the tank of cryogen,

429
00:17:24,175 --> 00:17:26,645
so you would have
  a continuing tank.

430
00:17:26,678 --> 00:17:28,180
There was a much
  cheaper, actually,

431
00:17:28,213 --> 00:17:30,582
way of doing it, which
provided better science,

432
00:17:30,615 --> 00:17:33,051
even though it made
 a smaller telescope,

433
00:17:33,084 --> 00:17:35,654
and I'm gonna talk about
that in a little bit.

434
00:17:35,687 --> 00:17:38,523
But, Lyman Spitzer was an expert
in the interstellar medium,

435
00:17:38,556 --> 00:17:40,792
so having an infrared telescope

436
00:17:40,825 --> 00:17:42,427
named after him is
 entirely appropriate,

437
00:17:42,460 --> 00:17:44,429
because the infrared,
 as we've just learned,

438
00:17:44,462 --> 00:17:46,131
is really great
  for understanding

439
00:17:46,164 --> 00:17:47,732
all the stuff between the stars,

440
00:17:47,765 --> 00:17:50,735
all that gas and dust which
 you can't see in the visible,

441
00:17:50,768 --> 00:17:52,337
you can see in the infrared.

442
00:17:52,370 --> 00:17:55,574
And Lyman would be really
  excited about that.

443
00:17:55,607 --> 00:17:56,741
Unfortunately, he passed away

444
00:17:56,774 --> 00:18:01,046
before the telescope
 was launched.

445
00:18:01,079 --> 00:18:03,115
And the other thing, this
  is the really cool part,

446
00:18:03,148 --> 00:18:05,250
is he was the first
  person to think of putting

447
00:18:05,283 --> 00:18:07,152
a telescope in space.

448
00:18:07,185 --> 00:18:08,887
He did this in 1946.

449
00:18:08,920 --> 00:18:11,022
And his idea led to the
Hubble Space Telescope.

450
00:18:11,055 --> 00:18:13,425
He was a huge proponent for
 the Hubble Space Telescope,

451
00:18:13,458 --> 00:18:15,026
and he's one of the
 driving influences

452
00:18:15,059 --> 00:18:16,595
in getting that launched.

453
00:18:16,628 --> 00:18:19,731
And the reason you wanna
put telescopes in space,

454
00:18:19,764 --> 00:18:22,634
not just infrared telescopes,
 but telescopes in space,

455
00:18:22,667 --> 00:18:23,935
they get you above
  the atmosphere,

456
00:18:23,968 --> 00:18:26,204
which is really
annoying to astronomers,

457
00:18:26,237 --> 00:18:27,873
because the atmosphere,
what it does,

458
00:18:27,906 --> 00:18:30,976
is it blurs your vision, so
 with an optical telescope,

459
00:18:31,009 --> 00:18:34,012
you can't see the fine
 resolution you want as well.

460
00:18:34,045 --> 00:18:36,715
And in the infrared
 light, actually,

461
00:18:36,748 --> 00:18:38,216
the atmosphere
 blocks a lot of the

462
00:18:38,249 --> 00:18:39,818
infrared wavelengths
 we're interested in.

463
00:18:39,851 --> 00:18:42,354
You can sort of see
some of the wavelengths

464
00:18:42,387 --> 00:18:45,357
Spitzer looks at from the
 ground, but not really well,

465
00:18:45,390 --> 00:18:47,359
so instead of blowing a
 hole through the atmosphere,

466
00:18:47,392 --> 00:18:50,228
you have to put your telescope
 above the atmosphere.

467
00:18:50,261 --> 00:18:53,165
There's another very good
  telescope called Sofia,

468
00:18:53,198 --> 00:18:55,066
I don't remember, it's
 like stratospheric,

469
00:18:55,099 --> 00:18:56,334
because it's on an airplane.

470
00:18:56,367 --> 00:18:58,937
So it's an infrared
 telescope on a 747,

471
00:18:58,970 --> 00:19:01,306
and that flies up to
about 40 thousand feet,

472
00:19:01,339 --> 00:19:03,074
so it's above most of the
  water in the atmosphere,

473
00:19:03,107 --> 00:19:04,576
which is the big problem.

474
00:19:04,609 --> 00:19:07,345
especially if you're looking
 for water somewhere else,

475
00:19:07,378 --> 00:19:10,048
you don't wanna see the
water in the atmosphere.

476
00:19:10,081 --> 00:19:11,449
So anyways, it's
  a good idea to get

477
00:19:11,482 --> 00:19:14,419
your telescope away
 from the atmosphere,

478
00:19:14,452 --> 00:19:16,522
because that makes it
 hard to see things.

479
00:19:17,689 --> 00:19:20,258
Even though it's really
good for us otherwise.

480
00:19:20,291 --> 00:19:21,726
Okay, so the Spitzer
 Space Telescope,

481
00:19:21,759 --> 00:19:23,395
let's give some stats to it now.

482
00:19:23,428 --> 00:19:25,830
It's an 85 centimeter,
 infrared telescope.

483
00:19:25,863 --> 00:19:27,999
Now, 85 centimeters is
 smaller than a mirror.

484
00:19:28,032 --> 00:19:29,834
It's... and there it is.

485
00:19:29,867 --> 00:19:31,303
That's the telescope, actually

486
00:19:31,336 --> 00:19:34,639
before it was encased in a tube,
and had all its instruments

487
00:19:34,672 --> 00:19:36,875
and the cryogenic tank put
  underneath it and stuff,

488
00:19:36,908 --> 00:19:38,276
and you can kind of
 get the scale for it,

489
00:19:38,309 --> 00:19:41,012
because there's two
 normal sized people,

490
00:19:41,045 --> 00:19:43,081
I think this was at JPL.

491
00:19:45,550 --> 00:19:46,851
And it's very shiny,
 because you want

492
00:19:46,884 --> 00:19:48,620
your mirror to be reflective.

493
00:19:48,653 --> 00:19:51,223
There's a secondary mirror
  under that column there,

494
00:19:51,256 --> 00:19:53,925
and the telescope was made
  entirely of beryllium.

495
00:19:53,958 --> 00:19:56,027
The mirror's solid beryllium,
 and the reason why,

496
00:19:56,060 --> 00:19:58,563
is that when you cool it
  down to the temperatures,

497
00:19:58,596 --> 00:20:01,566
you wanna cool infrared
telescopes down to,

498
00:20:01,599 --> 00:20:04,570
you don't want the
  mirror to shrink.

499
00:20:05,337 --> 00:20:07,939
So it has to be
thermally stable,

500
00:20:07,972 --> 00:20:09,874
at very low temperatures,

501
00:20:09,907 --> 00:20:12,811
and the low temperatures
in this case are

502
00:20:12,844 --> 00:20:17,048
between five and 12 degrees
 above absolute zero.

503
00:20:17,081 --> 00:20:19,084
The reason you want
 the mirror that cold,

504
00:20:19,117 --> 00:20:21,386
is if the mirror
isn't that cold,

505
00:20:21,419 --> 00:20:25,257
then you see the infrared
  radiation from the mirror,

506
00:20:25,290 --> 00:20:27,025
and then that takes
 away the signals

507
00:20:27,058 --> 00:20:28,360
that you're interested in.

508
00:20:30,728 --> 00:20:31,896
Okay.

509
00:20:31,929 --> 00:20:33,531
And there are three
instruments on Spitzer.

510
00:20:33,564 --> 00:20:37,302
One was, had a very
 useful acronym, IRAC,

511
00:20:37,335 --> 00:20:40,138
with the infrared array camera,
and so set of four cameras,

512
00:20:40,171 --> 00:20:43,408
that operate from
 three to nine microns.

513
00:20:43,441 --> 00:20:45,243
I was trying to think of
 a... what a good analogy...

514
00:20:45,276 --> 00:20:48,780
so a micron is a
 millionth of a meter,

515
00:20:48,813 --> 00:20:52,217
and 70 microns is about
  the width of a human hair,

516
00:20:52,250 --> 00:20:54,620
so it's a pretty tiny...

517
00:20:56,487 --> 00:20:58,023
size for the wavelength.

518
00:20:58,056 --> 00:21:01,293
But the longest wavelength
  we can see with our eyes,

519
00:21:01,326 --> 00:21:03,795
is about .8 microns, that's
 about as red as you can go,

520
00:21:03,828 --> 00:21:05,430
I think bees and dogs can see

521
00:21:05,463 --> 00:21:08,033
slightly farther
  into our infrared,

522
00:21:08,066 --> 00:21:11,703
but, so this is between
what's, .8, so you know,

523
00:21:11,736 --> 00:21:14,839
it's like four or
 five times the size,

524
00:21:14,872 --> 00:21:17,175
of visible light
  going out further,

525
00:21:17,208 --> 00:21:20,178
the spectrographs,
 disperse the light...

526
00:21:21,679 --> 00:21:24,249
From five to 38 microns,
and that instrument

527
00:21:24,282 --> 00:21:28,019
was called the IRS
 Infrared Spectrograph.

528
00:21:28,052 --> 00:21:29,287
And then there was a
 set of cameras with

529
00:21:29,320 --> 00:21:32,991
much longer wavelengths,
24, 70 and 160 microns,

530
00:21:33,024 --> 00:21:34,526
and that had the acronym, MIPS,

531
00:21:34,559 --> 00:21:39,364
so it was the Multi-imaging
 Band Photometer for Spitzer.

532
00:21:41,065 --> 00:21:43,435
And all these three
 instruments give us different

533
00:21:43,468 --> 00:21:46,871
wavelength ranges, and
  view on the universe, and,

534
00:21:46,904 --> 00:21:48,506
no, no, that's not the ...

535
00:21:48,539 --> 00:21:50,942
Come on ...
 Laser pointer.

536
00:21:50,975 --> 00:21:51,810
Alright, anyways.

537
00:21:53,044 --> 00:21:56,047
IRAC and MIPS show
  us that protostar

538
00:21:56,080 --> 00:21:58,049
we showed you earlier, okay.

539
00:21:58,082 --> 00:22:01,286
And the reddest
 colors are for MIPS,

540
00:22:01,319 --> 00:22:04,055
and the bluish and green
 are from IRAC in that image.

541
00:22:04,088 --> 00:22:07,959
And then, what we're seeing
 in the diagram there,

542
00:22:07,992 --> 00:22:10,862
is a plot of brightness, is
 a function of wavelength,

543
00:22:10,895 --> 00:22:13,064
and that's from IRS,
 and what you can see,

544
00:22:13,097 --> 00:22:16,434
is that it's rising in
general, the protostar,

545
00:22:16,467 --> 00:22:18,136
as you get to longer
and longer wavelengths,

546
00:22:18,169 --> 00:22:19,437
because it's a sort
 of cool object,

547
00:22:19,470 --> 00:22:21,539
so it's brighter at
 longer wavelengths,

548
00:22:21,572 --> 00:22:24,442
and then you see all these
  dips in the spectrum,

549
00:22:24,475 --> 00:22:26,344
those troughs and
stuff, and those are due

550
00:22:26,377 --> 00:22:30,982
to different materials
 absorbing some of the light,

551
00:22:31,015 --> 00:22:33,952
the gas and dust in
 front of the star,

552
00:22:33,985 --> 00:22:36,755
the protostar, actually,
  so you can see water, ice,

553
00:22:36,788 --> 00:22:38,223
there's a line to
  methyl alcohol,

554
00:22:38,256 --> 00:22:40,058
so it tells you about the
  chemical constituents,

555
00:22:40,091 --> 00:22:42,026
so spectroscopy
  is really powerful

556
00:22:42,059 --> 00:22:44,662
if you wanna understand what
 something is made out of,

557
00:22:44,695 --> 00:22:47,165
not just where it
 is, or how hot it is.

558
00:22:49,167 --> 00:22:50,268
Okay.

559
00:22:50,301 --> 00:22:51,903
So Spitzer had a
few innovations,

560
00:22:51,936 --> 00:22:54,372
which are fantastic
and other observatories

561
00:22:54,405 --> 00:22:56,941
are copying them now, because
 we've learned from Spitzer.

562
00:22:56,974 --> 00:22:58,877
The first thing,
 and this was another

563
00:22:58,910 --> 00:23:00,445
good thing for an
 infrared telescope,

564
00:23:00,478 --> 00:23:03,148
is you have to get it
  away from a really bright

565
00:23:03,181 --> 00:23:04,883
infrared source,
 which is the Earth.

566
00:23:04,916 --> 00:23:07,218
The Earth gives out a lot
  of infrared radiation.

567
00:23:07,251 --> 00:23:08,720
So Spitzer was designed to be an

568
00:23:08,753 --> 00:23:10,922
Earth trailing orbit
 around the sun.

569
00:23:12,423 --> 00:23:13,258
Thank you.

570
00:23:14,826 --> 00:23:16,728
I'll give it back, okay.

571
00:23:16,761 --> 00:23:18,263
Oh, that's so much better.

572
00:23:19,397 --> 00:23:20,465
I'm gonna go crazy
 with the pointer now.

573
00:23:20,498 --> 00:23:21,333
No, I won't.

574
00:23:23,334 --> 00:23:26,538
So, getting Spitzer
 away from the Earth

575
00:23:26,571 --> 00:23:29,407
meant that you're getting it
 away from this huge heat bath,

576
00:23:29,440 --> 00:23:31,443
which also allowed you
 to do something called

577
00:23:31,476 --> 00:23:33,645
passive cooling, because
you're away from the heat bath,

578
00:23:33,678 --> 00:23:35,680
and this is a really
 neat, and also,

579
00:23:35,713 --> 00:23:37,182
it sounds really simple concept,

580
00:23:37,215 --> 00:23:39,350
but it's really hard when you
 actually do the engineering.

581
00:23:39,383 --> 00:23:40,785
Except now, people
  know how to do it,

582
00:23:40,818 --> 00:23:43,254
so they made it look, they
made the hard look really easy.

583
00:23:43,287 --> 00:23:46,791
And basically, the idea is
  that the telescope here,

584
00:23:46,824 --> 00:23:48,059
so remember, I showed
 you the mirror,

585
00:23:48,092 --> 00:23:50,528
it's inside this tube,
 there's a shiny side,

586
00:23:50,561 --> 00:23:52,697
which is always pointing
towards the sun, which is good,

587
00:23:52,730 --> 00:23:54,833
because those are solar
  rays, which power Spitzer,

588
00:23:54,866 --> 00:23:56,301
so you need power to power it,

589
00:23:56,334 --> 00:23:59,037
and the side in the
 back is painted black,

590
00:23:59,070 --> 00:24:01,372
and that radiates to cold space.

591
00:24:01,405 --> 00:24:04,742
Because Spitzer is always in
 the shadow of the solar rays,

592
00:24:04,775 --> 00:24:07,779
so it's, the tube
 itself gets very cold,

593
00:24:07,812 --> 00:24:09,380
just by the fact that you keep

594
00:24:09,413 --> 00:24:11,549
starlight away from it,
sunlight away from it,

595
00:24:11,582 --> 00:24:13,685
and that's the only
 heat source going on.

596
00:24:13,718 --> 00:24:14,853
Then down at the
  bottom, actually,

597
00:24:14,886 --> 00:24:16,354
is all the warm electronics,

598
00:24:16,387 --> 00:24:18,423
so those are actually warm
  because they're powered

599
00:24:18,456 --> 00:24:20,758
and there's things like
heaters and computers

600
00:24:20,791 --> 00:24:22,293
and stuff that
 keep it pretty hot.

601
00:24:22,326 --> 00:24:24,162
In the back, there
 are two star trackers,

602
00:24:24,195 --> 00:24:27,131
which help Spitzer tell
  itself where it's pointed,

603
00:24:27,164 --> 00:24:28,633
'cause that's very important.

604
00:24:28,666 --> 00:24:30,635
If you wanna look at
 something you wanna make sure

605
00:24:30,668 --> 00:24:32,971
you can actually point
 the telescope to it.

606
00:24:33,004 --> 00:24:35,807
So this passive
 cooling is the thing

607
00:24:35,840 --> 00:24:37,876
that allowed Spitzer
 to keep going,

608
00:24:37,909 --> 00:24:41,079
'cause even after we ran
  out of the tank of helium,

609
00:24:41,946 --> 00:24:43,515
it's still very cold.

610
00:24:44,549 --> 00:24:45,984
Before, what it also did,

611
00:24:46,017 --> 00:24:48,319
is allowed us to keep
  that tank of helium small,

612
00:24:48,352 --> 00:24:50,588
because we didn't have to
  cool the whole telescope

613
00:24:50,621 --> 00:24:52,991
as much as you would if it
  wasn't passively cooled,

614
00:24:53,024 --> 00:24:56,194
and it also allowed us to
 adaptively cool the telescope.

615
00:24:56,227 --> 00:24:58,062
So we had a tank of helium,

616
00:24:58,095 --> 00:24:59,864
and then we'd had
  a little heater.

617
00:24:59,897 --> 00:25:01,399
So it's kind of
  counter intuitive.

618
00:25:01,432 --> 00:25:04,035
You heat the helium, you allow
 it to pass through a tube,

619
00:25:04,068 --> 00:25:06,037
and then that tube,
 the helium goes up

620
00:25:06,070 --> 00:25:10,542
and it cools the mirror, so
 the more you heat the tank,

621
00:25:10,575 --> 00:25:11,943
the more helium flows through,

622
00:25:11,976 --> 00:25:13,244
so when we're doing the longest

623
00:25:13,277 --> 00:25:15,179
wavelength
observations with MIPS,

624
00:25:15,212 --> 00:25:18,116
we cool the mirror more, because
the longer the wavelength,

625
00:25:18,149 --> 00:25:19,885
the colder you want
 your telescope.

626
00:25:22,219 --> 00:25:23,421
Okay.

627
00:25:23,454 --> 00:25:26,324
The one downside to this
Earth trailing orbit,

628
00:25:26,357 --> 00:25:29,227
is that Spitzer is getting
 farther away from the Earth

629
00:25:29,260 --> 00:25:31,563
every year, and that's
complicating things now,

630
00:25:31,596 --> 00:25:34,365
because we're way
 beyond how far away

631
00:25:34,398 --> 00:25:36,200
we thought we would
 be from the Earth.

632
00:25:36,233 --> 00:25:37,936
So the Earth's down
 here, and every year,

633
00:25:37,969 --> 00:25:39,537
Spitzer will recede
 further and further,

634
00:25:39,570 --> 00:25:42,674
so in April, 2006, which
was, that was our goal,

635
00:25:42,707 --> 00:25:43,942
if we got that, we were happy.

636
00:25:43,975 --> 00:25:46,210
Spitzer was gonna
  be that far away.

637
00:25:46,243 --> 00:25:49,213
When we ran out of coolant
 and started the warm mission,

638
00:25:49,246 --> 00:25:50,982
it was this far away,
 and here are now,

639
00:25:51,015 --> 00:25:52,450
almost toward the
  15th anniversary,

640
00:25:52,483 --> 00:25:56,921
it's 1.6 astronomical
  units away from the Earth,

641
00:25:56,954 --> 00:25:58,923
so it's further
 away from the Earth

642
00:25:58,956 --> 00:26:01,559
than either Spitzer or the Earth

643
00:26:01,592 --> 00:26:03,227
is away from the sun.

644
00:26:03,260 --> 00:26:06,731
And running to a problem
  now, because of geometry,

645
00:26:06,764 --> 00:26:10,034
because we keep the solar rays
 pointed at the sun to power,

646
00:26:10,067 --> 00:26:13,204
but we have to point, let
 me just go back a second...

647
00:26:13,237 --> 00:26:15,139
I can go back a second?
Yes.

648
00:26:15,172 --> 00:26:17,575
At the bottom here,
that's the antennae that

649
00:26:17,608 --> 00:26:19,644
we have to point back to
 Earth to get the data down,

650
00:26:19,677 --> 00:26:21,546
so you can take all
 the data you want,

651
00:26:21,579 --> 00:26:24,148
but if you don't get it
down to the astronomers,

652
00:26:24,181 --> 00:26:26,217
then you got a lot
 of grumpy astronomers

653
00:26:26,250 --> 00:26:27,285
and no good science.

654
00:26:28,386 --> 00:26:29,821
So now, every time we do this,

655
00:26:29,854 --> 00:26:31,923
I'm gonna put this stuff down
 for a second, so I can...

656
00:26:31,956 --> 00:26:35,360
So, we gotta keep the solar
 rays pointed to the sun,

657
00:26:35,393 --> 00:26:37,028
and then the Earth's
 off to the side,

658
00:26:37,061 --> 00:26:38,730
so we point the antennae...

659
00:26:39,563 --> 00:26:40,598
Which is my elbow here,

660
00:26:40,631 --> 00:26:42,734
to the Earth, but as we do that,

661
00:26:42,767 --> 00:26:45,136
as we get further and
 further away from the Earth,

662
00:26:45,169 --> 00:26:46,371
and you'll just kinda...

663
00:26:46,404 --> 00:26:48,406
you guys can puzzle
 this out as you...

664
00:26:48,439 --> 00:26:52,010
We have to point the
 telescope further away

665
00:26:52,043 --> 00:26:54,245
from pointing the
  solar rays so that

666
00:26:54,278 --> 00:26:57,015
the sunlight hits it
 at a 90 degree angle.

667
00:26:57,048 --> 00:26:59,751
And when we do that, the
 solar rays get less efficient,

668
00:26:59,784 --> 00:27:01,552
just like the solar
 rays on your roof

669
00:27:01,585 --> 00:27:02,887
would get less
 efficient, you know,

670
00:27:02,920 --> 00:27:04,822
depending upon the
  angle of incidence

671
00:27:04,855 --> 00:27:08,560
of the light of the sun as
 it, you know, rises and sets.

672
00:27:09,593 --> 00:27:11,029
And that's a
 problem, because now,

673
00:27:11,062 --> 00:27:13,398
when we're downlinking data,
 we're at the point now,

674
00:27:13,431 --> 00:27:17,969
we've reached the point
  actually, in 2013, where,

675
00:27:18,002 --> 00:27:19,404
no actually, no, it was a
 little bit further, I'm sorry,

676
00:27:19,437 --> 00:27:23,474
when we get towards 2016,
we're no longer power positive.

677
00:27:23,507 --> 00:27:26,344
We don't get enough
 light from the sun,

678
00:27:26,377 --> 00:27:30,648
when we're downlinking
data, to power Spitzer,

679
00:27:30,681 --> 00:27:32,717
but fortunately,
 Spitzer has a battery,

680
00:27:32,750 --> 00:27:35,219
which gets charged, usually,
when the sunlight's hitting it,

681
00:27:35,252 --> 00:27:37,255
but now we're draining the
  battery during downlinks,

682
00:27:37,288 --> 00:27:39,557
and that means we can
only spend so much time

683
00:27:39,590 --> 00:27:42,627
during downlink because we
 can't drain the battery fully,

684
00:27:42,660 --> 00:27:44,095
because then, Spitzer dies.

685
00:27:44,128 --> 00:27:45,863
So there's a finite
 amount of time

686
00:27:45,896 --> 00:27:47,532
that we can spend
  downlinking data,

687
00:27:47,565 --> 00:27:50,234
and that's getting less
and less each year.

688
00:27:50,267 --> 00:27:52,003
Upshot of that, means
 that we can take

689
00:27:52,036 --> 00:27:54,472
less and less science
 data each year,

690
00:27:54,505 --> 00:27:57,642
each time between downlinks,
 because it's getting

691
00:27:57,675 --> 00:27:59,577
harder and harder
  to communicate.

692
00:27:59,610 --> 00:28:01,946
There's also some things
 with things like sun sensors,

693
00:28:01,979 --> 00:28:03,614
which tell us how close
to the sun we are,

694
00:28:03,647 --> 00:28:06,050
and during downlinks, we
 have to turn those off now.

695
00:28:06,083 --> 00:28:08,653
Which engineers don't
 like to turn off

696
00:28:08,686 --> 00:28:10,354
things that help keep you safe

697
00:28:10,387 --> 00:28:11,723
and keep you from
 pointing to the sun,

698
00:28:11,756 --> 00:28:14,426
but they weren't useful anymore.

699
00:28:15,626 --> 00:28:17,228
Okay, so now, here's a
 little bit of science.

700
00:28:17,261 --> 00:28:20,932
This is science of the
 plane of our galaxy,

701
00:28:20,965 --> 00:28:24,836
and what you're gonna see
  here, is a map with IRAC,

702
00:28:24,869 --> 00:28:27,004
of pretty much the entire
  plane of our galaxy,

703
00:28:27,037 --> 00:28:28,806
and I'm not going
  to show it all.

704
00:28:28,839 --> 00:28:32,276
And what you're seeing is,
  so, as it's going through,

705
00:28:32,309 --> 00:28:34,712
we're seeing the plane, because
remember, The Milky, okay.

706
00:28:34,745 --> 00:28:37,048
First, we're seeing the
galactic center in the infrared,

707
00:28:37,081 --> 00:28:38,516
which you can see the
 center of the galaxy,

708
00:28:38,549 --> 00:28:41,219
where in the visible light,
 it's entirely opaque,

709
00:28:41,252 --> 00:28:43,321
and you see a lot of
emissions, there's my favorite,

710
00:28:43,354 --> 00:28:45,323
snakes going whizzing by us.

711
00:28:46,724 --> 00:28:49,393
And what we're looking
at, is we're in the disc

712
00:28:49,426 --> 00:28:50,295
of the Milky Way.

713
00:28:51,495 --> 00:28:54,398
And so, our galaxy is
 seeing edge on to us,

714
00:28:54,431 --> 00:28:56,267
so when we look at
  the entire galaxy,

715
00:28:56,300 --> 00:28:57,769
it's a strip in the sky.

716
00:28:57,802 --> 00:28:59,003
If you look up in
  a really dark sky,

717
00:28:59,036 --> 00:29:01,005
you see the Milky Way, you know,

718
00:29:01,038 --> 00:29:04,041
a glowing band of light, and
 it's dark in some places,

719
00:29:04,074 --> 00:29:06,344
which is where you have the
 dust that's obscuring it.

720
00:29:06,377 --> 00:29:07,812
Well, you're seeing
 the dust now,

721
00:29:07,845 --> 00:29:09,380
and you're seeing
 the stars behind it.

722
00:29:09,413 --> 00:29:11,516
In fact, in the infrared light,

723
00:29:11,549 --> 00:29:14,252
you're seeing more stars than
 you can see in visible light,

724
00:29:14,285 --> 00:29:17,522
because of all that gas
and dust between us.

725
00:29:17,555 --> 00:29:19,357
And you'll see something,
  objects that are red,

726
00:29:19,390 --> 00:29:22,527
you'll see bubbles,
where stars that are hot

727
00:29:22,560 --> 00:29:25,363
have blown the gas and
 dust away from them,

728
00:29:25,396 --> 00:29:27,431
that's a kind of
common feature you see.

729
00:29:27,464 --> 00:29:29,066
This is a star
 forming region here,

730
00:29:29,099 --> 00:29:31,202
we see all these
 pillars and chimneys,

731
00:29:31,235 --> 00:29:35,506
as the mass of stars are born
 they carve out the material

732
00:29:35,539 --> 00:29:38,142
into structures which you'll
 see repeated over and over,

733
00:29:38,175 --> 00:29:40,478
and then as we get
  towards the outer galaxy,

734
00:29:40,511 --> 00:29:42,180
you don't see much
 of anything at all,

735
00:29:42,213 --> 00:29:45,616
because most of the action
 is going towards the center.

736
00:29:45,649 --> 00:29:47,685
But basically, in this
image, if I let it play,

737
00:29:47,718 --> 00:29:49,654
and I'm not gonna go
 all the way through,

738
00:29:49,687 --> 00:29:54,458
90% of all the stars in the
 galaxy are in this strip.

739
00:29:54,491 --> 00:29:56,327
And most of the
 material that stars

740
00:29:56,360 --> 00:29:58,029
are made out of is in the strip.

741
00:29:58,062 --> 00:30:00,331
There's plenty of
 other material around,

742
00:30:00,364 --> 00:30:03,367
but most of the action
  is in a very narrow band,

743
00:30:03,400 --> 00:30:05,269
which we call the Milky
Way, it's our edge,

744
00:30:05,302 --> 00:30:08,472
that's the, you know, we're
 seeing our galaxy edge on.

745
00:30:08,505 --> 00:30:09,941
And what we're able
 to do with Spitzer,

746
00:30:09,974 --> 00:30:13,511
with its infrared eyes, is
 look at all the stars in that.

747
00:30:15,112 --> 00:30:17,815
And when we did it,
 we're able to come up

748
00:30:17,848 --> 00:30:19,750
with an idea what the
 galaxy looks like,

749
00:30:19,783 --> 00:30:21,986
so this is an excellent
artist concept,

750
00:30:22,019 --> 00:30:24,222
by one of my
colleagues, Robert Hurt.

751
00:30:24,255 --> 00:30:26,991
All the graphics you see, or
 pretty much all the graphics,

752
00:30:27,024 --> 00:30:28,860
Robert and his colleague
Tim Pile have made,

753
00:30:28,893 --> 00:30:30,995
they're fantastic in that.

754
00:30:31,028 --> 00:30:33,197
They're able to do
  scientific visualization,

755
00:30:33,230 --> 00:30:35,733
which is scientifically
 accurate for the most part,

756
00:30:35,766 --> 00:30:39,203
and I'll tell you when
it isn't, if I remember.

757
00:30:39,236 --> 00:30:41,839
But it also is pretty
 pleasing to the eye.

758
00:30:41,872 --> 00:30:43,441
So this is our
  best understanding

759
00:30:43,474 --> 00:30:45,610
of what the Milky
  Way looks like.

760
00:30:45,643 --> 00:30:48,179
Based on mapping stars as seen

761
00:30:48,212 --> 00:30:49,914
with Spitzer in the infrared.

762
00:30:49,947 --> 00:30:52,083
We used a very particular
  type of star in this case,

763
00:30:52,116 --> 00:30:53,985
something called
  a Red Clump Giant,

764
00:30:54,018 --> 00:30:54,952
where you know what
the brightness

765
00:30:54,985 --> 00:30:56,754
of that star
should be,

766
00:30:56,787 --> 00:30:58,890
so if you know the
 brightness of the star

767
00:30:58,923 --> 00:31:00,491
and you see how...

768
00:31:00,524 --> 00:31:03,261
You see the brightness
 you measure,

769
00:31:03,294 --> 00:31:06,297
then you can determine how far
 away it is, because you know,

770
00:31:06,330 --> 00:31:09,700
every distance that a
  star moves away from you,

771
00:31:09,733 --> 00:31:11,602
if it's twice as far
 away its brightness

772
00:31:11,635 --> 00:31:13,004
drops by a factor of four.

773
00:31:13,037 --> 00:31:14,639
So you can actually
figure out the distance

774
00:31:14,672 --> 00:31:16,841
by measuring how
  bright a star is,

775
00:31:16,874 --> 00:31:18,976
if you know what the
 brightness should be.

776
00:31:19,009 --> 00:31:20,444
It's a standard candle.

777
00:31:20,477 --> 00:31:22,046
And we can see
  most of the stars,

778
00:31:22,079 --> 00:31:25,116
because we're looking
  through the gas and dust.

779
00:31:25,149 --> 00:31:27,785
But not quite, so this
  is a great artist concept

780
00:31:27,818 --> 00:31:29,453
and it's showing us,
 so we're like, here.

781
00:31:29,486 --> 00:31:31,255
This is where the Earth is,

782
00:31:31,288 --> 00:31:34,258
kind of in between two spiral
 arms, we got a nice structure,

783
00:31:34,291 --> 00:31:37,962
and we can see to the bar
 in the center of the galaxy.

784
00:31:37,995 --> 00:31:41,799
It doesn't serve alcohol,
  it's just a bar of stars,

785
00:31:41,832 --> 00:31:44,101
but what's going on in
the back, we don't know.

786
00:31:44,134 --> 00:31:45,503
That's kind of
 conjecture actually,

787
00:31:45,536 --> 00:31:47,538
because we can only see
so far with Spitzer,

788
00:31:47,571 --> 00:31:50,708
we can see to about, like this.

789
00:31:50,741 --> 00:31:53,978
And the reason is, there's so
 many stars, it's so crowded,

790
00:31:54,011 --> 00:31:57,114
that you need a bigger
telescope with higher resolution

791
00:31:57,147 --> 00:31:59,850
to be able to look to the
  far side of the galaxy.

792
00:31:59,883 --> 00:32:02,586
Which is something that a
 new mission, called WFIRST,

793
00:32:02,619 --> 00:32:05,323
which is in the planning
 stages, should be able to do.

794
00:32:05,356 --> 00:32:07,224
If we point it at our Milky Way,

795
00:32:07,257 --> 00:32:08,693
we'll be able to
  map the structure

796
00:32:08,726 --> 00:32:11,396
of the entire galaxy,
  which is pretty fantastic.

797
00:32:13,464 --> 00:32:15,433
Okay, so that brings
 us to the next,

798
00:32:15,466 --> 00:32:16,901
and this is something
 we never thought

799
00:32:16,934 --> 00:32:18,135
we would do at Spitzer.

800
00:32:18,168 --> 00:32:19,603
Because usually, when you do it,

801
00:32:19,636 --> 00:32:22,807
you build an observatory,
  a science observatory,

802
00:32:22,840 --> 00:32:24,208
you come up with a science case,

803
00:32:24,241 --> 00:32:26,711
and then you design
 the telescope

804
00:32:26,744 --> 00:32:28,980
and the instruments to
  support that science case,

805
00:32:29,013 --> 00:32:30,881
so you can do the
science you want it to.

806
00:32:30,914 --> 00:32:32,817
And Spitzer had that
 and had four goals,

807
00:32:32,850 --> 00:32:34,652
and to be honest, I can't
 remember what they are now,

808
00:32:34,685 --> 00:32:36,053
they were all very
  exciting, though.

809
00:32:36,086 --> 00:32:37,722
And we were able to do them all.

810
00:32:37,755 --> 00:32:40,725
But one of the things we
did not have as a goal,

811
00:32:40,758 --> 00:32:43,694
was to study exoplanets,
 mainly because there was like,

812
00:32:43,727 --> 00:32:45,563
one exoplanet that
  was discovered

813
00:32:45,596 --> 00:32:47,398
when Spitzer was getting built,

814
00:32:47,431 --> 00:32:50,234
and we did not know
 that we'd be able

815
00:32:50,267 --> 00:32:52,403
to learn about
exoplanets with Spitzer.

816
00:32:52,436 --> 00:32:54,772
And it ends up, though,
Spitzer is a fantastic

817
00:32:54,805 --> 00:32:57,708
observatory to learn
 about exoplanets.

818
00:32:57,741 --> 00:32:59,276
The types of exoplanets we
  learn about with Spitzer,

819
00:32:59,309 --> 00:33:02,079
there's several different
 ways you can study exoplanets,

820
00:33:02,112 --> 00:33:04,849
one is, if it's far
  enough away from its star,

821
00:33:04,882 --> 00:33:09,120
and its mass big enough,
like a super Jupiter,

822
00:33:09,153 --> 00:33:10,588
you could directly image it.

823
00:33:10,621 --> 00:33:14,091
And there's a few planets that
 have been imaged that way.

824
00:33:14,124 --> 00:33:18,562
Another way, is by looking
  at the spectra of the star

825
00:33:18,595 --> 00:33:20,898
and all the spectra
 for stars have...

826
00:33:22,266 --> 00:33:25,736
lines, like sodium
  vapor lamps, in,

827
00:33:25,769 --> 00:33:27,838
street lamps,
 actually, have lines,

828
00:33:27,871 --> 00:33:29,673
if you were to
 point a spectrometer

829
00:33:29,706 --> 00:33:32,309
which breaks the light up into
 its different wavelengths,

830
00:33:32,342 --> 00:33:34,378
or a prism will do that for you.

831
00:33:34,411 --> 00:33:37,615
And what you see
 with a spectrometer,

832
00:33:37,648 --> 00:33:40,551
is that those lines
will move back and forth

833
00:33:40,584 --> 00:33:42,987
because the star's getting
  tugged by something.

834
00:33:43,020 --> 00:33:45,589
So if a planet's around it
  and it's in a right orbit,

835
00:33:45,622 --> 00:33:48,025
and it's massive enough,
  it'll tug the star enough

836
00:33:48,058 --> 00:33:51,429
that you can actually
 measure that motion.

837
00:33:51,462 --> 00:33:53,597
Just like police
officers measure

838
00:33:53,630 --> 00:33:55,366
our motion with a radar gun.

839
00:33:55,399 --> 00:33:57,668
It's a very similar
  thing, they're doing the,

840
00:33:57,701 --> 00:34:00,237
they're using a doppler
shift with your car.

841
00:34:00,270 --> 00:34:04,575
You can also do that with
  emission lines from stars,

842
00:34:04,608 --> 00:34:07,178
if they're getting
 tugged by a planet,

843
00:34:07,211 --> 00:34:09,046
and that's another
 technique that's done.

844
00:34:09,079 --> 00:34:10,347
Spitzer doesn't do
  either of those,

845
00:34:10,380 --> 00:34:12,216
it does something,
 one thing very well,

846
00:34:12,249 --> 00:34:14,318
it looks for
 transiting exoplanets.

847
00:34:14,351 --> 00:34:16,320
So these are planets
 just by geometry,

848
00:34:16,353 --> 00:34:18,222
we're just lucky enough,
there's the planets

849
00:34:18,255 --> 00:34:21,392
orbiting around its
 star, as we see it.

850
00:34:21,425 --> 00:34:23,627
So here's the star,
 planet goes around,

851
00:34:23,660 --> 00:34:25,863
and then goes in
  front of the star.

852
00:34:25,896 --> 00:34:28,466
Like this, and then what
happens is that planet

853
00:34:28,499 --> 00:34:30,167
blocks out a portion
 of the star light,

854
00:34:30,200 --> 00:34:32,570
because the planet isn't
brighter than the star,

855
00:34:32,603 --> 00:34:33,771
and that's what we see here.

856
00:34:33,804 --> 00:34:36,273
So if we're looking
here, so this is a plot,

857
00:34:36,306 --> 00:34:38,176
as a function of
  time essentially.

858
00:34:39,576 --> 00:34:42,746
Actually time measured in units
of the year of that planet,

859
00:34:42,779 --> 00:34:44,715
that's what this
 orbital phase means.

860
00:34:44,748 --> 00:34:47,418
And then you see this dip here,
so this is the star light,

861
00:34:47,451 --> 00:34:49,320
and all of a sudden,
 it goes, "dup", drops.

862
00:34:49,353 --> 00:34:52,089
Because the planet's blocking
 out some of the star light.

863
00:34:52,122 --> 00:34:54,425
It's not a very big dip,
if you can read this,

864
00:34:54,458 --> 00:34:59,230
it's like one, and this is .975,
it's only a couple percent,

865
00:34:59,263 --> 00:35:02,099
because the planet is much
  smaller than the star.

866
00:35:02,132 --> 00:35:04,135
But the size of that
 dip tells us the size

867
00:35:04,168 --> 00:35:05,469
of the planet relative the star,

868
00:35:05,502 --> 00:35:07,271
so if you know the
  size of the star,

869
00:35:07,304 --> 00:35:09,974
and astronomers can figure out
 sizes of stars pretty well,

870
00:35:10,007 --> 00:35:11,475
you know what the
 size of the planet is,

871
00:35:11,508 --> 00:35:14,512
just by watching it go
 in front of the star.

872
00:35:14,545 --> 00:35:16,680
Then, as the planet
 goes around the star,

873
00:35:16,713 --> 00:35:18,682
now we look at the bottom
  graph here, so this

874
00:35:18,715 --> 00:35:20,918
is the same plot, but
 we've zoomed it in,

875
00:35:20,951 --> 00:35:22,153
so you don't see the
 depth of the transit,

876
00:35:22,186 --> 00:35:24,889
gonna be down through
 the floor here,

877
00:35:24,922 --> 00:35:26,757
but you see two more dips...

878
00:35:28,158 --> 00:35:30,528
Which are when the planet
  goes behind the star,

879
00:35:30,561 --> 00:35:32,163
because we're looking
 at the infrared,

880
00:35:32,196 --> 00:35:35,132
the planet's fairly warm, so
 it's glowing in its own light,

881
00:35:35,165 --> 00:35:36,667
and when that day
  side of the planet

882
00:35:36,700 --> 00:35:39,971
goes behind the star, you lose
 the light from the planet.

883
00:35:41,405 --> 00:35:43,374
So, since you already know
  the size of the planet,

884
00:35:44,508 --> 00:35:46,210
you can measure the
 size of the dip,

885
00:35:46,243 --> 00:35:47,845
then you can figure
 out the temperature

886
00:35:47,878 --> 00:35:50,147
of this day side of the planet.

887
00:35:50,180 --> 00:35:52,683
Based on the amount of
 light that you've lost

888
00:35:52,716 --> 00:35:55,619
from the planet when it
goes behind the star.

889
00:35:55,652 --> 00:35:57,755
And now, most of
all the planets,

890
00:35:57,788 --> 00:36:01,192
we study with this
 transiting exoplanet, are ...

891
00:36:02,759 --> 00:36:05,629
Are tidally locked to their
 star, they're orbiting

892
00:36:05,662 --> 00:36:07,431
close enough to their stars,
 usually, because otherwise,

893
00:36:07,464 --> 00:36:10,334
it would take a really
 long time to see a transit,

894
00:36:11,868 --> 00:36:14,972
that they always
 show the same face,

895
00:36:15,005 --> 00:36:17,041
the planet shows the
 same face to the star,

896
00:36:17,074 --> 00:36:18,275
it's sort of like the moon,

897
00:36:18,308 --> 00:36:19,743
we only see one
  face of the moon,

898
00:36:19,776 --> 00:36:23,414
as the moon orbits the
Earth, it also rotates,

899
00:36:23,447 --> 00:36:25,349
but it keeps the same
 face facing the Earth,

900
00:36:25,382 --> 00:36:26,917
because it's
 orbiting very close,

901
00:36:26,950 --> 00:36:28,819
these planets do the same thing.

902
00:36:28,852 --> 00:36:31,188
So, when it's going
 around the orbit,

903
00:36:31,221 --> 00:36:34,725
we see the dark
 side, the back side,

904
00:36:34,758 --> 00:36:38,596
of the planet in transit,
 and then as it goes around,

905
00:36:38,629 --> 00:36:40,231
we see more and more
 of the day side,

906
00:36:40,264 --> 00:36:41,832
and that's what
 you're seeing here.

907
00:36:41,865 --> 00:36:44,501
So you see the day
 side, you see the dip,

908
00:36:44,534 --> 00:36:46,370
do it going behind the star,

909
00:36:46,403 --> 00:36:48,439
which is when you
 have no planet at all,

910
00:36:48,472 --> 00:36:50,741
and then you see
  the smooth curve,

911
00:36:50,774 --> 00:36:54,144
as it goes from day to night.

912
00:36:54,177 --> 00:36:56,413
And then finally, it
  transits and you block out

913
00:36:56,446 --> 00:36:59,316
some of the star, so
that changes everything.

914
00:36:59,349 --> 00:37:01,585
Now, going from day to
 night, tells you about

915
00:37:01,618 --> 00:37:05,189
the temperature difference
between the day and night side.

916
00:37:05,222 --> 00:37:07,157
And if you don't see any
temperature difference

917
00:37:07,190 --> 00:37:09,159
between day and night, then
 it tells you that something

918
00:37:09,192 --> 00:37:11,662
has to transport energy
from the day side,

919
00:37:11,695 --> 00:37:14,131
where the sunlight's hitting
 it, to the night side.

920
00:37:15,866 --> 00:37:18,569
And even if it doesn't,
if it's moving,

921
00:37:18,602 --> 00:37:20,070
you know, you see
  some difference,

922
00:37:20,103 --> 00:37:22,273
it tells you about how
 energy's transported

923
00:37:22,306 --> 00:37:24,008
from the day side
  to the night side.

924
00:37:24,041 --> 00:37:25,676
So this is a way
 of telling us about

925
00:37:25,709 --> 00:37:29,413
the atmosphere and
 the winds on planets.

926
00:37:29,446 --> 00:37:32,082
So we can actually say
 something about winds

927
00:37:32,115 --> 00:37:33,917
and planets around other stars,

928
00:37:33,950 --> 00:37:35,986
just by looking at the
light curve of the star.

929
00:37:36,019 --> 00:37:37,421
So you have to remember here,

930
00:37:37,454 --> 00:37:38,989
none of this do we actually
 see the planet, right,

931
00:37:39,022 --> 00:37:41,625
we're not resolving the
 planet relative to its star,

932
00:37:41,658 --> 00:37:45,195
we're just seeing the change
 in brightness of the star,

933
00:37:45,228 --> 00:37:47,031
when a planet passes
 in front of it.

934
00:37:48,598 --> 00:37:50,567
Okay, but Spitzer wasn't
designed to do that,

935
00:37:50,600 --> 00:37:52,102
so we had to do some tricks,

936
00:37:52,135 --> 00:37:55,205
because when we tried to do
 this, what we found out...

937
00:37:55,238 --> 00:37:57,541
I'll go a little bit
quick because it's so...

938
00:37:57,574 --> 00:38:00,177
This is a plot made by my
  colleague, Jim Ingalls.

939
00:38:00,210 --> 00:38:02,646
Is that if we measure
  the brightness of a star,

940
00:38:02,679 --> 00:38:05,883
on a part of the
 camera for Spitzer,

941
00:38:05,916 --> 00:38:07,184
it's brighter in one spot,

942
00:38:07,217 --> 00:38:09,353
that's what the
 purplish number means,

943
00:38:09,386 --> 00:38:11,789
and then as we go down to
 white, it gets less bright.

944
00:38:11,822 --> 00:38:14,591
And this changes
  by a few percent.

945
00:38:14,624 --> 00:38:18,629
Which, if we go back and
look at this HD189733,

946
00:38:18,662 --> 00:38:20,831
there's only a couple
percent for the transit,

947
00:38:20,864 --> 00:38:23,967
and for the eclipses,
  it's much less than that.

948
00:38:24,000 --> 00:38:28,038
So we're trying to measure
  very small changes here,

949
00:38:28,071 --> 00:38:30,841
with a camera where,
 just the fact that

950
00:38:30,874 --> 00:38:35,045
a star's here instead of
  here, it's a huge change.

951
00:38:35,078 --> 00:38:37,247
And this is only one pixel of
 the camera, so what we do now,

952
00:38:37,280 --> 00:38:41,752
is we hold the star
 steady on the camera,

953
00:38:41,785 --> 00:38:43,654
but just like my hand,
  and of course I'm nervous,

954
00:38:43,687 --> 00:38:45,155
which is why my
  hand's jittering,

955
00:38:45,188 --> 00:38:47,358
but the spacecraft
  wobbles because we didn't

956
00:38:47,391 --> 00:38:48,892
design it not to do that, right,

957
00:38:48,925 --> 00:38:51,462
because there's no reason
  to have it point that well

958
00:38:51,495 --> 00:38:54,231
to do all the things that
 Spitzer was supposed to do,

959
00:38:54,264 --> 00:38:56,100
and then, so all scientists
 said to the engineers,

960
00:38:56,133 --> 00:38:58,969
well, stop the wobble,
and they said, we can't,

961
00:38:59,002 --> 00:39:02,373
because it's part of the, you
 know, we never designed it

962
00:39:02,406 --> 00:39:04,475
to do that but they
 could do some things.

963
00:39:05,675 --> 00:39:06,643
Which I'll get to
  in just a second,

964
00:39:06,676 --> 00:39:08,212
so if we look at
a light curve...

965
00:39:09,246 --> 00:39:10,981
From another
 transiting exoplanet,

966
00:39:11,014 --> 00:39:12,783
and there's a transit
 in here, actually,

967
00:39:12,816 --> 00:39:14,918
there's an eclipse in here,
 you'll have to believe me.

968
00:39:14,951 --> 00:39:16,487
You see, you get these
 percent variations,

969
00:39:16,520 --> 00:39:18,589
and that's due to the
wobble of the spacecraft

970
00:39:18,622 --> 00:39:21,058
and the fact that the
cameras aren't perfect.

971
00:39:22,859 --> 00:39:24,495
The engineers figured
 out a way to keep the,

972
00:39:24,528 --> 00:39:26,730
and this is actually after
  we cut the wobble down,

973
00:39:26,763 --> 00:39:28,932
by stopping the
 cycling of a battery.

974
00:39:28,965 --> 00:39:30,701
I'm sorry, a heater
 for a battery,

975
00:39:30,734 --> 00:39:32,936
because we needed
 to keep the battery

976
00:39:32,969 --> 00:39:36,140
for Spitzer warm so
 that it didn't freeze,

977
00:39:36,173 --> 00:39:38,041
because you know, we
  keep it passively cooled,

978
00:39:38,074 --> 00:39:40,944
and ends up that heater
would flip on and off,

979
00:39:40,977 --> 00:39:43,480
and it would kind of shake
 the telescope a little bit.

980
00:39:43,513 --> 00:39:44,848
And then we're turn,
 they've allowed us

981
00:39:44,881 --> 00:39:46,316
to turn the heater setting down,

982
00:39:46,349 --> 00:39:48,318
so it only shook, it shook
  it a little bit less,

983
00:39:48,351 --> 00:39:49,620
which was a good thing.

984
00:39:49,653 --> 00:39:51,321
But it still shook it.

985
00:39:51,354 --> 00:39:52,923
But then, going back just one,

986
00:39:52,956 --> 00:39:55,959
knowing this map, so
you know how it varies,

987
00:39:55,992 --> 00:39:59,196
and seeing it vary,
 you can take that out.

988
00:39:59,229 --> 00:40:01,465
It's not magic, it's
 data processing,

989
00:40:01,498 --> 00:40:03,367
which leads you to science.

990
00:40:03,400 --> 00:40:05,536
And folks like Jim
  and Jessica Crick

991
00:40:05,569 --> 00:40:08,372
are really good at doing this,
 and people in the community,

992
00:40:08,405 --> 00:40:10,274
and then okay, so you still
 don't see the transit here

993
00:40:10,307 --> 00:40:11,809
because the data's still noisy,

994
00:40:11,842 --> 00:40:13,811
that's just normal
 noise, so what you do,

995
00:40:13,844 --> 00:40:18,449
is you add data together,
  sum it up in average,

996
00:40:18,482 --> 00:40:20,818
and then you can see
the dip for the eclipse.

997
00:40:20,851 --> 00:40:24,621
Which is, let's see, it's
  like a tenth of a percent,

998
00:40:24,654 --> 00:40:26,724
it's a very small fluctuation.

999
00:40:27,891 --> 00:40:29,526
And then you can
  fit a model to it,

1000
00:40:29,559 --> 00:40:32,863
and that model helps tell
  you about the brightness,

1001
00:40:32,896 --> 00:40:34,364
the temperature of the planet,

1002
00:40:34,397 --> 00:40:37,168
the day side temperature of
 the planet at this wavelength.

1003
00:40:38,935 --> 00:40:40,170
Okay.

1004
00:40:40,203 --> 00:40:41,271
And that's what we
  do with Spitzer,

1005
00:40:41,304 --> 00:40:42,773
so the first
detections of emission,

1006
00:40:42,806 --> 00:40:44,308
thermal emission
from exoplanets,

1007
00:40:44,341 --> 00:40:46,543
was done by Spitzer,
just like I've told you.

1008
00:40:46,576 --> 00:40:49,179
And so that's by Dave
 Charbonneau and Drake Deming,

1009
00:40:49,212 --> 00:40:50,581
they did almost
  at the same time,

1010
00:40:50,614 --> 00:40:52,783
they had a joint press
 release, it was very exciting,

1011
00:40:52,816 --> 00:40:54,084
and these planets
  are hot, right,

1012
00:40:54,117 --> 00:40:56,019
they're thousands
  of degrees Kelvin,

1013
00:40:56,052 --> 00:40:57,554
because if they
  weren't that hot,

1014
00:40:57,587 --> 00:40:59,456
then they wouldn't emit
  enough infrared radiation

1015
00:40:59,489 --> 00:41:01,091
for Spitzer to be
  able to see them,

1016
00:41:01,124 --> 00:41:02,359
and this is commonplace now.

1017
00:41:02,392 --> 00:41:03,994
So these are things
 called hot Jupiters,

1018
00:41:04,027 --> 00:41:05,496
they're about the
  size of Jupiter,

1019
00:41:05,529 --> 00:41:08,398
but they're in much closer to
 their star than Jupiter is,

1020
00:41:08,431 --> 00:41:10,100
they're more like in
 the orbit of Mercury.

1021
00:41:10,133 --> 00:41:11,902
So they get heated up,
 a high temperature,

1022
00:41:11,935 --> 00:41:14,938
and this is a class of planet
 which we didn't know existed

1023
00:41:14,971 --> 00:41:17,808
until Spitzer and Kepler
started studying them.

1024
00:41:19,609 --> 00:41:20,844
Okay.

1025
00:41:20,877 --> 00:41:22,880
So then, actually,
  and this was done

1026
00:41:22,913 --> 00:41:25,249
before Spitzer ran out
 of CryoSys in 2006,

1027
00:41:25,282 --> 00:41:27,685
and then we ran out tank
shortly, well, in 2009.

1028
00:41:29,619 --> 00:41:31,788
So Spitzer heated up from
  the 12 Kelvin we used

1029
00:41:31,821 --> 00:41:33,791
to operate the
telescope, to 28 Kelvin.

1030
00:41:34,791 --> 00:41:36,727
And we knew that we
could probably do this,

1031
00:41:36,760 --> 00:41:38,128
so we know that.

1032
00:41:38,161 --> 00:41:39,897
Two, we figured that
 two of the cameras

1033
00:41:39,930 --> 00:41:41,331
on one instrument still
work, so this is IRAC

1034
00:41:41,364 --> 00:41:43,000
and this is the
 shortest wavelength

1035
00:41:43,033 --> 00:41:45,769
the 3.6 and 4.5 micron cameras.

1036
00:41:45,802 --> 00:41:47,771
And they'd work the
same as they did before,

1037
00:41:47,804 --> 00:41:50,040
and this is the
 first image we took

1038
00:41:50,073 --> 00:41:51,475
with them of a
 star-forming region.

1039
00:41:51,508 --> 00:41:53,443
I got to pick the region...

1040
00:41:53,476 --> 00:41:55,746
I thought it looked
pretty cool and it did.

1041
00:41:55,779 --> 00:41:58,482
But, we'd never been
 able to test this

1042
00:41:58,515 --> 00:42:00,717
because we weren't allowed to
 test the extended operations

1043
00:42:00,750 --> 00:42:02,686
because, "Nah, you're
  never gonna get that far."

1044
00:42:02,719 --> 00:42:04,421
And when we dialed
  in the numbers

1045
00:42:04,454 --> 00:42:07,591
to set the temperatures and
 everything, nothing worked.

1046
00:42:07,624 --> 00:42:11,261
It was a total... we tried to
 stabilize the temperatures,

1047
00:42:11,294 --> 00:42:15,198
instead we railed the
 heaters on the observatory,

1048
00:42:15,231 --> 00:42:17,601
and there were some choice
  words said by people,

1049
00:42:17,634 --> 00:42:19,036
and we tried to figure
 out what was going on.

1050
00:42:19,069 --> 00:42:21,739
And basically, we had sent a...

1051
00:42:22,839 --> 00:42:25,943
a 16-bit number to
control the temperature

1052
00:42:25,976 --> 00:42:27,444
because that's what
our documentation said,

1053
00:42:27,477 --> 00:42:30,113
and then when we looked at
 the actual wiring diagrams,

1054
00:42:30,146 --> 00:42:32,916
my colleague Bill Gwacham
 grabbed the wiring diagrams,

1055
00:42:32,949 --> 00:42:35,252
looked and said, "Well, you
 can't pass a 16-bit thing

1056
00:42:35,285 --> 00:42:37,688
"to this controller because
 it only takes 12 bits."

1057
00:42:37,721 --> 00:42:40,324
it's like "Oh, okay,
 we made a mistake."

1058
00:42:40,357 --> 00:42:42,426
So we're able to correct
it, which is why there's

1059
00:42:42,459 --> 00:42:45,228
a little bit of lag between
 when we ran out of cryogen,

1060
00:42:45,261 --> 00:42:46,697
and when we actually
 started operating.

1061
00:42:46,730 --> 00:42:48,699
Because we had
 clever engineering,

1062
00:42:48,732 --> 00:42:50,334
which said, we could continue,

1063
00:42:50,367 --> 00:42:52,736
but then we had to go
 figure out how to operate it

1064
00:42:52,769 --> 00:42:56,073
because we'd never operated
 in that mode before.

1065
00:42:56,106 --> 00:42:57,641
And you always have
 to check things

1066
00:42:57,674 --> 00:42:59,509
and this isn't
 some testing we did

1067
00:42:59,542 --> 00:43:01,211
on the ground prior to launch.

1068
00:43:02,779 --> 00:43:04,615
But we kinda knew
  it could happen,

1069
00:43:04,648 --> 00:43:07,151
so we were upset, but
 we figured it out.

1070
00:43:08,351 --> 00:43:09,586
Actually that was
  a bad day for me,

1071
00:43:09,619 --> 00:43:11,822
because I was monitoring
the telemetry,

1072
00:43:11,855 --> 00:43:13,290
I saw that we were,
 instead of being

1073
00:43:13,323 --> 00:43:16,259
at 28 Kelvin we were
 like at 50 Kelvin

1074
00:43:16,292 --> 00:43:17,794
and I'm like, "Oh that's bad."

1075
00:43:17,827 --> 00:43:19,630
And then I had to
  phone the folks...

1076
00:43:20,697 --> 00:43:21,598
who do the commanding
 and I said,

1077
00:43:21,631 --> 00:43:22,799
"Turn off the instrument.

1078
00:43:22,832 --> 00:43:24,334
"Because we don't want
 those heaters on."

1079
00:43:24,367 --> 00:43:25,836
Because we didn't know how
  much heat we would put in

1080
00:43:25,869 --> 00:43:27,904
and how look it'd
  take to cool down.

1081
00:43:27,937 --> 00:43:29,239
So you think,
 okay, you only have

1082
00:43:29,272 --> 00:43:31,041
two cameras on one instrument.

1083
00:43:31,074 --> 00:43:34,211
This is not a good situation
 around an observatory.

1084
00:43:34,244 --> 00:43:36,279
But, these wavelengths
 are really good

1085
00:43:36,312 --> 00:43:38,749
for the things like exoplanets
 and distant galaxies.

1086
00:43:38,782 --> 00:43:40,617
So it was even better
 than we imagined,

1087
00:43:40,650 --> 00:43:42,653
because now we could spend
  all our, not all our time,

1088
00:43:42,686 --> 00:43:43,854
but most of our time working on

1089
00:43:43,887 --> 00:43:45,455
exoplanets and distant galaxies.

1090
00:43:45,488 --> 00:43:47,591
And there are a lot of
astronomers who want to do this.

1091
00:43:47,624 --> 00:43:49,660
And there are a lot of
 cool results from it.

1092
00:43:50,760 --> 00:43:52,996
One of the results I'll show,

1093
00:43:53,029 --> 00:43:54,331
is looking at
 eclipse measurements

1094
00:43:54,364 --> 00:43:56,700
of another hot, not Jupiter,

1095
00:43:56,733 --> 00:43:58,735
because it's smaller than
 Jupiter, its more Earth size.

1096
00:43:58,768 --> 00:44:01,104
A planet called 55
Cancri e, which is also

1097
00:44:01,137 --> 00:44:03,874
orbiting very
 close to it's star.

1098
00:44:03,907 --> 00:44:05,342
And one thing we
  notice looking at

1099
00:44:05,375 --> 00:44:08,912
these eclipse measurements
  in 2012 and 2013,

1100
00:44:08,945 --> 00:44:11,982
is that the depths vary
  from 50 parts per million

1101
00:44:12,015 --> 00:44:16,019
to over 200 parts per
  million from 2012 to 2013.

1102
00:44:16,052 --> 00:44:18,522
So what that means, if you
 convert that to temperature,

1103
00:44:18,555 --> 00:44:19,823
is that the low temperature,

1104
00:44:19,856 --> 00:44:22,426
like down here, from
 the 2012 measurements,

1105
00:44:22,459 --> 00:44:25,328
was about 1300 Kelvin
 for that planet.

1106
00:44:25,361 --> 00:44:27,831
And then it jumps up
 to like 2800 Kelvin.

1107
00:44:27,864 --> 00:44:29,533
So what's going on right?

1108
00:44:29,566 --> 00:44:32,369
So now, this is good
  because now we have data,

1109
00:44:32,402 --> 00:44:33,870
which is telling us the
temperature's changing,

1110
00:44:33,903 --> 00:44:35,372
so now this gets all the people

1111
00:44:35,405 --> 00:44:37,708
who model exoplanets
 very excited,

1112
00:44:37,741 --> 00:44:39,876
because now they've got to
 figure out what's going on.

1113
00:44:39,909 --> 00:44:42,512
And one hypothesis, and
we can't confirm it,

1114
00:44:42,545 --> 00:44:44,214
and this is just an
 illustration, right?

1115
00:44:44,247 --> 00:44:46,717
We don't actually see the
  planet in any of this,

1116
00:44:46,750 --> 00:44:49,219
we just see a star
  and then we see it

1117
00:44:49,252 --> 00:44:53,190
get very fainter by little
  tiny fluctuations, right?

1118
00:44:53,223 --> 00:44:54,124
You wouldn't even be able to see

1119
00:44:54,157 --> 00:44:55,759
this fluctuation with your eye.

1120
00:44:55,792 --> 00:44:56,993
If I passed the, you know, if I

1121
00:44:57,026 --> 00:44:58,862
flipped through the
 images with you.

1122
00:44:58,895 --> 00:45:00,797
But what we think is
 happening is that,

1123
00:45:00,830 --> 00:45:03,133
because it's in
  close it's getting

1124
00:45:03,166 --> 00:45:05,769
tidally stretched and
  stuff, there's volcanism.

1125
00:45:05,802 --> 00:45:07,904
Volcanoes on this planet.

1126
00:45:07,937 --> 00:45:10,207
And in 2012, it was
 just less active

1127
00:45:10,240 --> 00:45:12,042
or maybe we're seeing
 a different portion

1128
00:45:12,075 --> 00:45:14,311
of the planet because
maybe it rotates slowly.

1129
00:45:14,344 --> 00:45:16,713
And in 2013, it's more active.

1130
00:45:16,746 --> 00:45:18,648
Or we're seeing the
 hotter side of it,

1131
00:45:18,681 --> 00:45:20,951
because maybe it isn't
totally tidally locked,

1132
00:45:20,984 --> 00:45:23,587
maybe it's rotating very
  slowly like Mercury does.

1133
00:45:24,754 --> 00:45:26,089
So that's a really
  exciting is that

1134
00:45:26,122 --> 00:45:27,624
we can start to
  understand something like,

1135
00:45:27,657 --> 00:45:31,028
if you can call this weather,
 weather on other planets.

1136
00:45:35,064 --> 00:45:37,634
And, in conjunction with Hubble,

1137
00:45:37,667 --> 00:45:39,970
we're able to identify
to most distant galaxy.

1138
00:45:41,104 --> 00:45:42,539
Okay, I'm gonna go through fast.

1139
00:45:42,572 --> 00:45:44,074
So this is some of the
  lights that we could see.

1140
00:45:44,107 --> 00:45:46,176
This galaxy hasn't
  aged, we see it

1141
00:45:46,209 --> 00:45:49,546
as it was 13.4
  billion years ago.

1142
00:45:49,579 --> 00:45:51,014
It's about 1/100 the
 size of the Milky Way

1143
00:45:51,047 --> 00:45:53,717
and we know this because we
can measure how far away it is.

1144
00:45:53,750 --> 00:45:57,254
It's redshift,
  essentially, by when it...

1145
00:45:57,287 --> 00:45:58,722
we can see the light from it.

1146
00:45:59,856 --> 00:46:01,858
Because basically,
  this line here

1147
00:46:01,891 --> 00:46:04,427
is when all the light that's
 at shorter wavelength,

1148
00:46:04,460 --> 00:46:06,396
that gets redshifted out,

1149
00:46:06,429 --> 00:46:08,965
gets absorbed by the
 gas in the galaxy.

1150
00:46:08,998 --> 00:46:10,400
So that's a very good...

1151
00:46:10,433 --> 00:46:12,402
You can model what the
galaxy should look like,

1152
00:46:12,435 --> 00:46:14,671
because you don't see
 it in one Hubble band,

1153
00:46:14,704 --> 00:46:16,139
you see it in the second.

1154
00:46:16,172 --> 00:46:19,075
And then you see the blob
  in the two IRAC bands.

1155
00:46:19,108 --> 00:46:23,213
So... what this is, is
 that the Hubble data

1156
00:46:23,246 --> 00:46:26,750
allows you to get the
 redshift or the time that...

1157
00:46:26,783 --> 00:46:28,552
You looking back to
 observe the galaxy,

1158
00:46:28,585 --> 00:46:30,787
and then Spitzer gives the
 mass and the age of the stars

1159
00:46:30,820 --> 00:46:32,956
because this is where
 all the starlight is.

1160
00:46:34,524 --> 00:46:35,759
Okay.

1161
00:46:35,792 --> 00:46:37,260
One other thing
 we're able to do is

1162
00:46:37,293 --> 00:46:38,795
there's another technique
  for looking at planets.

1163
00:46:38,828 --> 00:46:41,965
And these are planets, that
 you can't see any other way

1164
00:46:41,998 --> 00:46:43,834
because you can
 directly image them

1165
00:46:43,867 --> 00:46:45,202
if they're pretty far
 away from the star,

1166
00:46:45,235 --> 00:46:47,237
and you can use
  radial velocities

1167
00:46:47,270 --> 00:46:49,139
and transits if
  they're in close,

1168
00:46:49,172 --> 00:46:51,007
and they're either
  affecting the star passing

1169
00:46:51,040 --> 00:46:53,677
in front of it, but how
  about things like Jupiter.

1170
00:46:53,710 --> 00:46:54,878
How do you observe Jupiter?

1171
00:46:54,911 --> 00:46:56,346
Things that are
 round or snow lined.

1172
00:46:56,379 --> 00:46:57,881
Well, if you get really lucky

1173
00:46:57,914 --> 00:47:00,116
and you look at a lot of stars,

1174
00:47:00,149 --> 00:47:03,620
when stars pass in
front of other stars...

1175
00:47:05,455 --> 00:47:06,490
Nope, I'm sorry...

1176
00:47:12,228 --> 00:47:14,364
If they perfectly align,

1177
00:47:14,397 --> 00:47:17,968
the foreground star
 will gravitational,

1178
00:47:18,001 --> 00:47:19,836
and the gravity of
 that star will focus

1179
00:47:19,869 --> 00:47:21,304
the light of the
background star,

1180
00:47:21,337 --> 00:47:22,973
and that's what you're
  seeing here is this flip.

1181
00:47:23,006 --> 00:47:24,841
Is that the light gets
gravitationally focused

1182
00:47:24,874 --> 00:47:27,077
as the star passes in
front of the other star.

1183
00:47:27,110 --> 00:47:30,614
And if there's a
 planet with that star,

1184
00:47:30,647 --> 00:47:32,682
that can also
gravitationally interact

1185
00:47:32,715 --> 00:47:36,519
if the geometry's right, so,
 it doesn't happen that often.

1186
00:47:36,552 --> 00:47:38,822
If you look at a
  few million stars

1187
00:47:38,855 --> 00:47:40,390
over the course of a few months,

1188
00:47:40,423 --> 00:47:41,625
which people do from the ground,

1189
00:47:41,658 --> 00:47:43,093
you may see a thousand
 events where you see

1190
00:47:43,126 --> 00:47:45,629
a star brightened
  by another star.

1191
00:47:45,662 --> 00:47:48,365
And you may get
 three with a planet.

1192
00:47:48,398 --> 00:47:50,834
So that's what's done by
 people who study microlensing,

1193
00:47:50,867 --> 00:47:53,536
every year, when they can look
 at the center of our galaxy

1194
00:47:53,569 --> 00:47:56,506
where there's a lot of stars
 and you have a lot of chances

1195
00:47:56,539 --> 00:47:58,475
of stars going in
 front of other stars.

1196
00:48:00,677 --> 00:48:03,213
The problem with that
is, even if you do that,

1197
00:48:03,246 --> 00:48:06,049
you see the bump, you
 know there's a planet,

1198
00:48:06,082 --> 00:48:11,088
you don't know, you can't
 tell the mass and the distance

1199
00:48:11,955 --> 00:48:13,123
with just one measurement

1200
00:48:13,156 --> 00:48:14,691
because you only
 get one measurement

1201
00:48:16,092 --> 00:48:17,928
and everything can be
closer and less massive

1202
00:48:17,961 --> 00:48:19,996
or it can be further
 away and more massive.

1203
00:48:20,029 --> 00:48:22,332
And it's very hard to
  disentangle between those

1204
00:48:22,365 --> 00:48:24,167
if all you have is
  one light curve,

1205
00:48:24,200 --> 00:48:27,404
but since Spitzer's so
far away from the Earth,

1206
00:48:27,437 --> 00:48:28,972
if both Spitzer and Earth,

1207
00:48:29,005 --> 00:48:31,341
observe one of these
 microlensing events,

1208
00:48:31,374 --> 00:48:34,244
the time between when
 Spitzer observes the event,

1209
00:48:34,277 --> 00:48:37,948
which is the red, and when
  the Earth sees the event,

1210
00:48:37,981 --> 00:48:41,518
allows you to disentangle
  between mass and distance.

1211
00:48:41,551 --> 00:48:44,921
Because you're able to look at
 from two different positions.

1212
00:48:44,954 --> 00:48:46,823
You're able to
 pin-down the geometry.

1213
00:48:48,291 --> 00:48:49,426
And we're able to do this,
  and we've been doing this

1214
00:48:49,459 --> 00:48:50,894
for quite some time.

1215
00:48:50,927 --> 00:48:52,930
But the first observation
  we do with Spitzer...

1216
00:48:56,799 --> 00:48:57,968
Is that one there.

1217
00:48:58,001 --> 00:49:00,537
We actually got the
star, we actually saw...

1218
00:49:00,570 --> 00:49:02,272
So you see the
 star curve and then

1219
00:49:02,305 --> 00:49:03,740
that dip is due to the planet,

1220
00:49:03,773 --> 00:49:06,276
so we have a star and
  planet microlensing event

1221
00:49:06,309 --> 00:49:07,844
and we're able to determine
 the mass of the star

1222
00:49:07,877 --> 00:49:09,079
is 0.5 Jupiters.

1223
00:49:10,847 --> 00:49:13,883
The planet mass is not... no,
 I've got this the other way.

1224
00:49:13,916 --> 00:49:15,118
I'm very sorry.

1225
00:49:17,754 --> 00:49:20,390
The star mass is 7/10 the sun,

1226
00:49:20,423 --> 00:49:21,858
so it's a little
 smaller than the sun.

1227
00:49:21,891 --> 00:49:24,427
The planet is about
 half of Jupiter mass,

1228
00:49:24,460 --> 00:49:25,795
which is kind of interesting,

1229
00:49:25,828 --> 00:49:27,030
and it's the distance of three

1230
00:49:27,063 --> 00:49:30,533
astronomical units
  from it's star,

1231
00:49:30,566 --> 00:49:32,769
which we couldn't
  see any other way.

1232
00:49:32,802 --> 00:49:35,772
And Spitzer and the ground
routine, we do this every year,

1233
00:49:35,805 --> 00:49:38,074
we look at a handful of planets
with Spitzer and the ground

1234
00:49:38,107 --> 00:49:39,776
and we're learning about planets

1235
00:49:39,809 --> 00:49:41,644
that you can't see
  in any other way.

1236
00:49:41,677 --> 00:49:42,879
The only problem
 with this technique

1237
00:49:42,912 --> 00:49:44,214
is that once that
  alignment's gone,

1238
00:49:44,247 --> 00:49:46,116
that's the last time you
ever see that planet.

1239
00:49:46,149 --> 00:49:47,384
Which is a real bummer.

1240
00:49:47,417 --> 00:49:48,918
You can't go back and
 re-observe it because

1241
00:49:48,951 --> 00:49:51,521
you could never
 see, you don't see,

1242
00:49:51,554 --> 00:49:52,956
the lens in the first place.

1243
00:49:54,957 --> 00:49:56,126
Okay.

1244
00:49:56,159 --> 00:49:58,828
Alright, so it gets here
to the coolest thing

1245
00:49:58,861 --> 00:50:00,563
that I've ever had
 a chance to work on,

1246
00:50:00,596 --> 00:50:03,333
which is the observations
  of the TRAPPIST-1 system,

1247
00:50:03,366 --> 00:50:05,035
which maybe some
 of you heard about.

1248
00:50:05,068 --> 00:50:06,870
So this was a star,
that was only discovered

1249
00:50:06,903 --> 00:50:07,804
in the year 2000.

1250
00:50:07,837 --> 00:50:10,240
Its a very cold, red star,

1251
00:50:10,273 --> 00:50:12,409
and was discovered with
another infrared survey

1252
00:50:12,442 --> 00:50:15,779
which was done with JPL
  and Caltech called 2MASS.

1253
00:50:15,812 --> 00:50:18,615
It's at 40 light years
  away, but it's very small.

1254
00:50:18,648 --> 00:50:20,917
It's only 8/100 of a solar mass,

1255
00:50:20,950 --> 00:50:22,719
and it's about half the
temperature of the sun,

1256
00:50:22,752 --> 00:50:24,220
and it's only a little
bit bigger than Jupiter.

1257
00:50:24,253 --> 00:50:26,823
It's something called an
  ultra-cool dwarf, M dwarf.

1258
00:50:28,257 --> 00:50:32,028
And because it's so cold, it's
 four thousand times brighter

1259
00:50:32,061 --> 00:50:35,198
in the infrared than it is in
 the visible, which is good.

1260
00:50:35,231 --> 00:50:37,434
And since it's small, that means

1261
00:50:37,467 --> 00:50:39,569
that when a planet
 passes in front of it,

1262
00:50:39,602 --> 00:50:40,937
smaller planets
  are easier to see

1263
00:50:40,970 --> 00:50:43,606
around smaller
 stars, which is nice.

1264
00:50:43,639 --> 00:50:47,510
And we just happened to
see, so from the ground,

1265
00:50:47,543 --> 00:50:49,612
an astronomer named
 Caglioni was looking

1266
00:50:49,645 --> 00:50:52,282
to see if he could find
planets around very cold stars,

1267
00:50:52,315 --> 00:50:54,117
because we didn't know
if they would have them,

1268
00:50:54,150 --> 00:50:58,288
and he saw some transit-like
 things, but it looked weird.

1269
00:50:58,321 --> 00:51:00,457
It had this weird extra
hump to this and this,

1270
00:51:00,490 --> 00:51:01,858
and he wasn't sure
  what's going on.

1271
00:51:01,891 --> 00:51:03,626
So he asked for
  some Spitzer time

1272
00:51:03,659 --> 00:51:07,297
and then we got more odd
looking bumps as well.

1273
00:51:07,330 --> 00:51:09,633
So we didn't know what
was going on with this.

1274
00:51:11,100 --> 00:51:14,537
And so, we ended up spending
 a lot of time with Spitzer.

1275
00:51:14,570 --> 00:51:17,841
We spent 500 hours to
  just stare at the system,

1276
00:51:17,874 --> 00:51:19,576
which is something you
 can do with Spitzer

1277
00:51:19,609 --> 00:51:21,311
since it's not orbiting the...

1278
00:51:21,344 --> 00:51:22,812
it's not on the Earth, so
  you don't have to worry

1279
00:51:22,845 --> 00:51:24,848
about the sun coming
 up and ruining

1280
00:51:24,881 --> 00:51:27,050
your observations every
eight to 16 hours,

1281
00:51:27,083 --> 00:51:29,152
and it's not orbiting around
 the Earth like Hubble.

1282
00:51:29,185 --> 00:51:31,521
Every time Hubble
 looks at something,

1283
00:51:31,554 --> 00:51:33,823
Hubble's orbit, it's 90 minutes,

1284
00:51:33,856 --> 00:51:35,525
so it can look at something
 for about 40 minutes

1285
00:51:35,558 --> 00:51:36,659
and then it goes
behind the Earth

1286
00:51:36,692 --> 00:51:38,128
and can't see that source again

1287
00:51:38,161 --> 00:51:40,263
until it comes back
 around the other side.

1288
00:51:40,296 --> 00:51:41,965
But with Spitzer, we
 can look at something

1289
00:51:41,998 --> 00:51:44,667
between 40 days to a whole year

1290
00:51:44,700 --> 00:51:46,236
if we want to, and
  it, with TRAPPIST,

1291
00:51:46,269 --> 00:51:48,004
we could look at it for 40 days,

1292
00:51:48,037 --> 00:51:49,973
we spent 20 days looking at it.

1293
00:51:50,006 --> 00:51:51,875
And this is what we saw...
  So...

1294
00:51:53,509 --> 00:51:55,011
I'll give you the
  punch line is that

1295
00:51:55,044 --> 00:51:57,680
there's seven transiting
  planets around TRAPPIST-1.

1296
00:51:57,713 --> 00:51:59,482
The system has a set of planets

1297
00:51:59,515 --> 00:52:02,152
that are very closely
 packed, and remember,

1298
00:52:02,185 --> 00:52:03,520
because if for them to transit,

1299
00:52:03,553 --> 00:52:05,522
they have to pass
between us and the star.

1300
00:52:05,555 --> 00:52:08,925
So all their orbits are
in a nice, tight plane.

1301
00:52:08,958 --> 00:52:11,594
Which is a little bit
surprising, but not impossible.

1302
00:52:11,627 --> 00:52:14,330
So, we got kind of lucky with
 this, and this is a graphic.

1303
00:52:14,363 --> 00:52:16,499
And then, here's
 the data coming up,

1304
00:52:16,532 --> 00:52:18,368
so this is the Spitzer data,

1305
00:52:18,401 --> 00:52:19,903
and you can see there's the star

1306
00:52:19,936 --> 00:52:21,104
and there's a
 little bit of noise,

1307
00:52:21,137 --> 00:52:23,072
and then you see
 these periodic dips.

1308
00:52:23,105 --> 00:52:24,541
And when we saw this we thought,

1309
00:52:24,574 --> 00:52:26,509
"Well, wait a minute,
  there's a lot of transits.

1310
00:52:26,542 --> 00:52:28,778
"What the heck is going on?"

1311
00:52:28,811 --> 00:52:30,847
And you can see the transits

1312
00:52:30,880 --> 00:52:33,716
of the same size keep appearing.

1313
00:52:33,749 --> 00:52:35,118
Like this, you keep seeing,

1314
00:52:35,151 --> 00:52:37,187
well that one's during a
downlink, so you don't see it...

1315
00:52:37,220 --> 00:52:39,556
You also see some
 flares when the star

1316
00:52:39,589 --> 00:52:41,391
gets a little hot and burps.

1317
00:52:41,424 --> 00:52:45,962
But you can keep seeing
repeated dips of the same depth,

1318
00:52:45,995 --> 00:52:47,931
which means it's the
 same size planet,

1319
00:52:47,964 --> 00:52:49,432
So it's the same planet.

1320
00:52:49,465 --> 00:52:50,934
And then you can
  go and pick it out

1321
00:52:50,967 --> 00:52:53,803
and you can see the
 spacing between the planet,

1322
00:52:53,836 --> 00:52:58,074
the dips in time, so this
 is in days now we're seeing,

1323
00:52:58,107 --> 00:53:01,010
so every time you see
 that planet repeat

1324
00:53:01,043 --> 00:53:02,712
you know what the
period of the planet is

1325
00:53:02,745 --> 00:53:03,880
because it's making one orbit.

1326
00:53:03,913 --> 00:53:06,583
So for planet B here,
 that's 1.8 days.

1327
00:53:06,616 --> 00:53:09,352
So, you're able to tell
the size of the planet,

1328
00:53:09,385 --> 00:53:11,421
you're also able
to tell how long

1329
00:53:11,454 --> 00:53:13,189
it takes to go around it's star,

1330
00:53:13,222 --> 00:53:14,724
so that also tells
  you the distance

1331
00:53:14,757 --> 00:53:16,226
of the planet from the star.

1332
00:53:16,259 --> 00:53:18,962
And since you know how hot
  and bright the star is,

1333
00:53:18,995 --> 00:53:20,563
that also tells
  you how much heat

1334
00:53:20,596 --> 00:53:22,632
the planet gets from the star.

1335
00:53:22,665 --> 00:53:25,001
It tells us something about
 the temperature of the star.

1336
00:53:25,034 --> 00:53:26,670
So, we got a lot of information.

1337
00:53:27,770 --> 00:53:28,571
Now I've got to go
find the clicker again,

1338
00:53:28,604 --> 00:53:30,273
sorry about that...

1339
00:53:30,306 --> 00:53:31,774
Okay.

1340
00:53:31,807 --> 00:53:33,276
So the TRAPPIST-1 system
  is much smaller than ours,

1341
00:53:33,309 --> 00:53:35,645
here's seven planets
 closely packed system,

1342
00:53:35,678 --> 00:53:38,848
all would fit very comfortably
 inside the orbit of Mercury.

1343
00:53:38,881 --> 00:53:41,985
In fact, it's more like
what the Galilean Moons

1344
00:53:42,018 --> 00:53:43,586
look like in Jupiter.

1345
00:53:43,619 --> 00:53:45,488
It's kind of, in between.

1346
00:53:45,521 --> 00:53:48,258
And the star's, sort of,
  a little bit more massive

1347
00:53:48,291 --> 00:53:51,427
and about the same size
and radius as Jupiter,

1348
00:53:51,460 --> 00:53:54,130
so it's more similar to
what the Galilean system

1349
00:53:54,163 --> 00:53:55,999
looks like than our
 own solar system.

1350
00:53:57,166 --> 00:53:58,601
But that's not all,

1351
00:53:58,634 --> 00:54:00,937
'cause those planets
are so closely packed...

1352
00:54:06,876 --> 00:54:10,713
They tend to gravitationally
 interact with each other.

1353
00:54:10,746 --> 00:54:12,215
Not only are they closely packed

1354
00:54:12,248 --> 00:54:15,318
but they're in these things
 called resonance orbits.

1355
00:54:15,351 --> 00:54:17,520
What that means is that
every time B orbits,

1356
00:54:17,553 --> 00:54:19,989
hang on I can't find
 B, there it goes,

1357
00:54:20,022 --> 00:54:22,925
for eight orbits of
 B, C orbits five times

1358
00:54:22,958 --> 00:54:24,560
and D orbits three times,

1359
00:54:24,593 --> 00:54:26,429
during these three
  body resonances.

1360
00:54:26,462 --> 00:54:28,031
And what that means is
 there's a lot of times

1361
00:54:28,064 --> 00:54:30,566
when they pass in front of
each other in regular patterns,

1362
00:54:30,599 --> 00:54:33,570
and the whole pattern repeats
 about every 38.6 days.

1363
00:54:34,937 --> 00:54:36,873
And because of that,
  planets keep whizzing by,

1364
00:54:36,906 --> 00:54:39,309
they gravitationally
  interact with each other.

1365
00:54:39,342 --> 00:54:41,744
So they tug and
 pull on each other,

1366
00:54:41,777 --> 00:54:44,580
and that tug and pull, if
  you look at the transits,

1367
00:54:44,613 --> 00:54:46,215
so this is for TRAPPIST-1 D,

1368
00:54:46,248 --> 00:54:49,719
and I'm just showing you
 different transits observed

1369
00:54:49,752 --> 00:54:52,922
over a span of many months now.

1370
00:54:52,955 --> 00:54:55,625
And what you see is, if you
 look at the orange line,

1371
00:54:55,658 --> 00:54:58,027
that's where they
 all, all the midpoints

1372
00:54:58,060 --> 00:55:00,997
should line up if it's
 just orbiting around

1373
00:55:01,030 --> 00:55:02,799
in the period space constant.

1374
00:55:02,832 --> 00:55:04,834
But what we find is,
 it's not orbiting

1375
00:55:04,867 --> 00:55:06,202
around that period
  staying constant,

1376
00:55:06,235 --> 00:55:08,338
it's changing by minutes,

1377
00:55:08,371 --> 00:55:10,540
and the reason it's
 changing by minutes

1378
00:55:10,573 --> 00:55:14,210
is because the other
 planets, C and E,

1379
00:55:14,243 --> 00:55:15,712
are gravitationally interacting.

1380
00:55:15,745 --> 00:55:17,947
So they tug it one way and
  they tug it the other way.

1381
00:55:17,980 --> 00:55:21,050
So they speed it up and they
 slow it down in it's orbit.

1382
00:55:21,083 --> 00:55:23,153
So they change the
 timing of the transit.

1383
00:55:24,053 --> 00:55:25,855
And if you take enough data,

1384
00:55:25,888 --> 00:55:27,056
and you have a big
  enough computer,

1385
00:55:27,089 --> 00:55:28,024
and you're really clever,

1386
00:55:28,057 --> 00:55:29,525
and your name's Simon Grimm,

1387
00:55:29,558 --> 00:55:31,427
who's a really
 excellent astronomer,

1388
00:55:31,460 --> 00:55:32,829
you can take all
  that information,

1389
00:55:32,862 --> 00:55:35,198
because now you know
 the timing change,

1390
00:55:35,231 --> 00:55:38,034
you could figure out the
masses of the planets.

1391
00:55:38,067 --> 00:55:39,302
And that's amazing, right?

1392
00:55:39,335 --> 00:55:42,138
So now we know the size
and we know the mass.

1393
00:55:42,171 --> 00:55:44,207
So since we know the
 size of the planets,

1394
00:55:44,240 --> 00:55:45,441
they're all about Earth-size,

1395
00:55:45,474 --> 00:55:47,310
and the mass they're
 all about Earth-mass,

1396
00:55:47,343 --> 00:55:48,778
D's a little bit smaller,

1397
00:55:48,811 --> 00:55:51,013
we could figure out the
  density of these planets.

1398
00:55:51,046 --> 00:55:53,149
And this is amazing
 because this tells-

1399
00:55:53,182 --> 00:55:55,451
we can tell something
 about the bulk composition.

1400
00:55:55,484 --> 00:55:57,587
We could tell if they're
little balls of iron,

1401
00:55:57,620 --> 00:56:00,390
or big fluff balls of water
 or something in between.

1402
00:56:00,423 --> 00:56:02,392
They're all
 something in between.

1403
00:56:02,425 --> 00:56:03,626
And because of that then,

1404
00:56:03,659 --> 00:56:04,861
we can take it to
 the graphics folks,

1405
00:56:04,894 --> 00:56:06,229
because we have all
 this information,

1406
00:56:06,262 --> 00:56:08,431
if fact we have more
 information about the planets

1407
00:56:08,464 --> 00:56:12,502
in this system than any other
 system other than our own.

1408
00:56:12,535 --> 00:56:14,437
Where we can actually
go and see the planets.

1409
00:56:14,470 --> 00:56:16,105
We know the densities
 of all these planets

1410
00:56:16,138 --> 00:56:18,908
to about 10% or better,
which is outstanding,

1411
00:56:18,941 --> 00:56:21,611
because it's amazing, because
 these 40 light years away,

1412
00:56:21,644 --> 00:56:23,246
we can't even see these objects,

1413
00:56:23,279 --> 00:56:25,448
yet we know what
 they're densities are

1414
00:56:25,481 --> 00:56:28,251
and we know what their
 surface gravities are.

1415
00:56:28,284 --> 00:56:30,420
And because of that we
 can make conjectures

1416
00:56:30,453 --> 00:56:31,954
about what they
  should look like,

1417
00:56:31,987 --> 00:56:33,956
what their composition
 should look like.

1418
00:56:33,989 --> 00:56:35,892
So the things in
close, actually,

1419
00:56:35,925 --> 00:56:38,628
have a fair amount of
  water or gas or something,

1420
00:56:38,661 --> 00:56:41,931
because their densities are
lower than the Earth's density.

1421
00:56:41,964 --> 00:56:43,833
They're more like
  Venus densities.

1422
00:56:43,866 --> 00:56:46,903
So we think C is probably
  an analog to Venus.

1423
00:56:46,936 --> 00:56:49,939
D is probably something
  that's, it has, let's see,

1424
00:56:49,972 --> 00:56:52,041
it's density is less than Earth,

1425
00:56:52,074 --> 00:56:54,177
so it's probably got a
fair amount of something

1426
00:56:54,210 --> 00:56:57,580
lighter than rock on it,
  water, gas, we don't know,

1427
00:56:57,613 --> 00:57:00,016
we're thinking
 maybe it's waterish.

1428
00:57:00,049 --> 00:57:02,518
And then E is the one
 that's most Earth-like

1429
00:57:02,551 --> 00:57:05,221
in terms of density, it's about
the same density as Earth.

1430
00:57:05,254 --> 00:57:06,722
And as we get further out,

1431
00:57:06,755 --> 00:57:09,725
these planets are slightly
 less than dense than Earth,

1432
00:57:09,758 --> 00:57:12,028
which means that they
 have things like,

1433
00:57:13,195 --> 00:57:15,565
lighter than rock, so
 that's some sort of

1434
00:57:15,598 --> 00:57:17,900
like carbon-monoxide,
 water, methane,

1435
00:57:17,933 --> 00:57:19,635
what-have-you, that are lighter.

1436
00:57:19,668 --> 00:57:21,604
And those are probably
some form of atmosphere,

1437
00:57:21,637 --> 00:57:24,140
but since they're further
  away it's probably cold,

1438
00:57:24,173 --> 00:57:25,975
so it's probably
 in the form of ice.

1439
00:57:27,443 --> 00:57:29,312
Okay, I'm running over time
 here, I'm sorry about that.

1440
00:57:29,345 --> 00:57:32,515
So just compare it quickly to
 the solar system, if we map,

1441
00:57:32,548 --> 00:57:35,451
so this is the plot of density
 here, and there's the Earth,

1442
00:57:35,484 --> 00:57:37,086
and then illumination
 from the host star,

1443
00:57:37,119 --> 00:57:38,354
relative to Sun/Earth.

1444
00:57:38,387 --> 00:57:40,289
So what that tells us it
that if it's on one-one,

1445
00:57:40,322 --> 00:57:41,791
it should be very
 similar to the Earth,

1446
00:57:41,824 --> 00:57:44,727
so D has about the same amount
 of radiation coming from it,

1447
00:57:44,760 --> 00:57:46,662
so it might be about
 the same temperature.

1448
00:57:46,695 --> 00:57:51,000
And E is slightly cooler, but
 has about the same density,

1449
00:57:51,033 --> 00:57:53,302
so it could be very similar
 to Earth in properties,

1450
00:57:53,335 --> 00:57:55,037
but a colder version.

1451
00:57:55,070 --> 00:57:57,073
And then F and G are
 sort of like Mars,

1452
00:57:57,106 --> 00:57:58,774
so these extended
  envelopes, well,

1453
00:57:58,807 --> 00:58:00,042
it could be arid like Mars,

1454
00:58:00,075 --> 00:58:02,278
or it also could have
 icy compositions,

1455
00:58:02,311 --> 00:58:04,480
we don't know, but we know
  a lot about the system

1456
00:58:04,513 --> 00:58:06,949
and we can continue to explore.

1457
00:58:06,982 --> 00:58:08,518
So looking to the future,

1458
00:58:08,551 --> 00:58:09,919
Spitzer's going to
keep operating

1459
00:58:09,952 --> 00:58:13,356
until November 2019, and
  then for budgetary reasons

1460
00:58:13,389 --> 00:58:16,392
we're not going to continue,
 at least up til this point.

1461
00:58:16,425 --> 00:58:19,762
And we're gonna keep looking
 for planets around cool stars

1462
00:58:19,795 --> 00:58:21,230
and things that are
 even cooler than stars

1463
00:58:21,263 --> 00:58:24,200
called brown dwarfs, very
  similar to TRAPPIST-1.

1464
00:58:24,233 --> 00:58:25,835
Another thing we may
 do is measure the mass

1465
00:58:25,868 --> 00:58:27,770
of an isolated stellar
 mass black hole

1466
00:58:28,938 --> 00:58:30,806
and we're really looking
forward to the launch

1467
00:58:30,839 --> 00:58:34,443
of the James Webb Space
Telescope in 2021.

1468
00:58:34,476 --> 00:58:37,446
Which if you think of,
take Hubble and Spitzer

1469
00:58:37,479 --> 00:58:39,649
and combine them, so James Webb,

1470
00:58:39,682 --> 00:58:42,585
would be like the love
 child of Spitzer and Hubble,

1471
00:58:42,618 --> 00:58:43,853
and it's bigger and better.

1472
00:58:43,886 --> 00:58:46,122
And one of the things
 we'll be able to do

1473
00:58:46,155 --> 00:58:51,160
is actually start to give us
 ideas about the composition.

1474
00:58:52,261 --> 00:58:53,496
So are these pictures
 correct or not?

1475
00:58:53,529 --> 00:58:55,465
We'll be able to figure
that out, with, well...

1476
00:58:56,432 --> 00:58:57,600
Okay.

1477
00:58:57,633 --> 00:58:59,502
Well thank you very
much for your attention.

1478
00:58:59,535 --> 00:59:01,838
[applause]

1479
00:59:07,176 --> 00:59:10,913
So if you have any questions,
 please use the mic,

1480
00:59:10,946 --> 00:59:13,249
which is right in the
  center of the auditorium,

1481
00:59:13,282 --> 00:59:15,018
and just, yeah,
 come on up and ask.

1482
00:59:28,964 --> 00:59:30,232
>> Hi...

1483
00:59:30,265 --> 00:59:33,035
I had wondered if Spitzer

1484
00:59:33,068 --> 00:59:38,074
focused in on anything
 since SNR HBH3.

1485
00:59:40,609 --> 00:59:43,512
>> SNR HBH3, I'm not familiar
 with that, so you'll have to

1486
00:59:43,545 --> 00:59:48,184
tell me a little bit more
  >> Supernova remnant HBH3.

1487
00:59:48,217 --> 00:59:52,188
In the new star system
 that's just forming.

1488
00:59:53,288 --> 00:59:55,024
>> We haven't because
 no one submitted

1489
00:59:55,057 --> 00:59:57,727
a proposal to the
 best of my knowledge.

1490
00:59:57,760 --> 01:00:00,463
Somebody could go and do that.

1491
01:00:00,496 --> 01:00:02,331
One of the considerations
  with Spitzer is that

1492
01:00:02,364 --> 01:00:05,468
we don't get to see all of
  the sky all of the time.

1493
01:00:05,501 --> 01:00:07,403
We get to view a
strip of the sky

1494
01:00:07,436 --> 01:00:08,704
because depending
upon our geometry

1495
01:00:08,737 --> 01:00:10,306
with respect
to the Sun.

1496
01:00:10,339 --> 01:00:12,775
So, maybe that that system
  isn't available yet.

1497
01:00:12,808 --> 01:00:15,578
So, it's quite possible
that somebody right now

1498
01:00:15,611 --> 01:00:17,246
is writing a proposal
 and we'll be able

1499
01:00:17,279 --> 01:00:19,248
to observe it within the year.

1500
01:00:19,281 --> 01:00:20,883
>> Thank you.
  >> Carey: You're welcome.

1501
01:00:22,751 --> 01:00:24,854
>> Thanks for the great talk.
 >> Carey: You're welcome.

1502
01:00:24,887 --> 01:00:27,723
>> Two questions, on
 the TRAPPIST system,

1503
01:00:27,756 --> 01:00:31,060
has there been any
atmospheric spectroscopy

1504
01:00:31,093 --> 01:00:35,531
that's been teased out of
  any infrared signatures?

1505
01:00:35,564 --> 01:00:38,868
>> So, we tried a little
bit, by looking at

1506
01:00:38,901 --> 01:00:41,837
the two Spitzer channels,
  the 3.6 and 4.5 micron

1507
01:00:41,870 --> 01:00:44,273
to see if we could see a
difference in the depth,

1508
01:00:44,306 --> 01:00:46,142
which would be indicative
  of an atmosphere

1509
01:00:46,175 --> 01:00:48,144
because you're selectively
  blocking light,

1510
01:00:48,177 --> 01:00:50,246
and there wasn't enough
signal to do that.

1511
01:00:50,279 --> 01:00:52,281
Now, Hubble's also looked at it

1512
01:00:52,314 --> 01:00:54,150
and they get a depth
  very similar to Spitzer's

1513
01:00:54,183 --> 01:00:55,651
so what they're
  able to rule out,

1514
01:00:55,684 --> 01:00:57,720
with a shorter
wavelength spectroscopy,

1515
01:00:57,753 --> 01:01:00,923
is that these planets
 don't, at least B, C, and D,

1516
01:01:00,956 --> 01:01:02,925
which I think is all
 Hubble's observed,

1517
01:01:02,958 --> 01:01:05,561
don't have extended
 hydrogen envelopes,

1518
01:01:05,594 --> 01:01:07,530
which is good if you're
 interested in thinking about

1519
01:01:07,563 --> 01:01:09,866
things that aren't just
big balls of hydrogen.

1520
01:01:11,066 --> 01:01:14,270
>> And second
question, on 55 Cancri,

1521
01:01:14,303 --> 01:01:16,806
the jump in heat after
 all the volcanism,

1522
01:01:17,673 --> 01:01:19,275
is there thoughts on that?

1523
01:01:19,308 --> 01:01:21,711
That it's atmospheric blanketing

1524
01:01:21,744 --> 01:01:25,581
where it's keeping it in or...

1525
01:01:25,614 --> 01:01:26,949
Is there other ways to rule out

1526
01:01:26,982 --> 01:01:29,719
shadowing from the atmosphere?

1527
01:01:29,752 --> 01:01:32,254
>> So, there's no conclusive
 to go one way or the other.

1528
01:01:32,287 --> 01:01:35,491
So, yeah, the atmospheric
  properties and blanketing

1529
01:01:35,524 --> 01:01:39,895
due to high level
 particulates, is one scenario.

1530
01:01:39,928 --> 01:01:41,764
Another one is just geometry,

1531
01:01:41,797 --> 01:01:43,799
and we're seeing some
change in the properties

1532
01:01:43,832 --> 01:01:46,102
because it is not
  tidally locked,

1533
01:01:47,536 --> 01:01:49,472
and there's no way, with
 just the data points we have

1534
01:01:49,505 --> 01:01:52,374
to distinguish between those.

1535
01:01:52,407 --> 01:01:53,909
One of the things though
will be interesting,

1536
01:01:53,942 --> 01:01:55,878
and people are continuing
 to take data on this system,

1537
01:01:55,911 --> 01:01:58,581
is to see if they see
 any repeating patterns

1538
01:01:58,614 --> 01:02:00,416
or something that,
which would be cyclical,

1539
01:02:00,449 --> 01:02:01,917
and then you could
 say something about...

1540
01:02:01,950 --> 01:02:05,187
You know, if you see something
 reoccurring on some cadence,

1541
01:02:05,220 --> 01:02:08,991
then that will in credence
  to some hypothesis.

1542
01:02:09,024 --> 01:02:11,360
But yeah, no, there's nothing
 that distinguishes between,

1543
01:02:11,393 --> 01:02:13,863
I think there's like four
  or five different ways

1544
01:02:13,896 --> 01:02:16,465
of potentially explaining
  the change in temperature

1545
01:02:16,498 --> 01:02:17,666
that was observed.

1546
01:02:17,699 --> 01:02:18,534
>> Thanks.

1547
01:02:21,537 --> 01:02:23,539
>> Good evening.
  My question is...

1548
01:02:23,572 --> 01:02:27,243
Do you see any potential
in finding an exomoon...

1549
01:02:27,276 --> 01:02:28,778
using Spitzer?

1550
01:02:28,811 --> 01:02:30,246
Because I know that,

1551
01:02:30,279 --> 01:02:32,214
potentially if you have a large
enough planet you might have

1552
01:02:32,247 --> 01:02:33,582
like an Earth size moon
>> Carey: Yep.

1553
01:02:33,615 --> 01:02:35,184
>> or possibly even
 slightly larger.

1554
01:02:35,217 --> 01:02:37,586
So it's not totally
 outlandish, I think.

1555
01:02:37,619 --> 01:02:40,055
>> No, it's certainly
 possible to do that.

1556
01:02:40,088 --> 01:02:41,323
In fact with the TRAPPIST,

1557
01:02:41,356 --> 01:02:43,492
with the very odd
 transit signatures,

1558
01:02:43,525 --> 01:02:46,195
that was one of the hypotheses
 that was batted about.

1559
01:02:46,228 --> 01:02:49,131
But then when people tried
  to fit a two-body system,

1560
01:02:49,164 --> 01:02:52,468
you know, a planet with a fairly

1561
01:02:52,501 --> 01:02:55,037
reasonably-sized moon,
 it didn't work out.

1562
01:02:55,070 --> 01:02:57,173
So, it's certainly possible...

1563
01:02:58,440 --> 01:02:59,875
People are looking for that,

1564
01:02:59,908 --> 01:03:03,445
primarily with ground
based observations, now.

1565
01:03:03,478 --> 01:03:05,548
And haven't come up
 with any moons yet,

1566
01:03:05,581 --> 01:03:07,316
so that's, I think that's
  telling us something.

1567
01:03:07,349 --> 01:03:10,319
Maybe that's telling
 us that, yet again,

1568
01:03:10,352 --> 01:03:14,990
that our solar system
 is maybe not common.

1569
01:03:15,023 --> 01:03:16,258
>> Inquirer: Okay.
  >> Yeah, so...

1570
01:03:16,291 --> 01:03:17,793
but people are looking
 for things like that.

1571
01:03:17,826 --> 01:03:19,728
>> Okay, and my
 second question is,

1572
01:03:19,761 --> 01:03:21,764
If you've somehow
 had infinite budget,

1573
01:03:21,797 --> 01:03:24,800
how long could you ride
Spitzer down in flames

1574
01:03:24,833 --> 01:03:26,535
before it just could not
give you data anymore?

1575
01:03:26,568 --> 01:03:27,903
>> That's a really
  good question,

1576
01:03:27,936 --> 01:03:32,241
and I don't have a very
crisp answer to that

1577
01:03:32,274 --> 01:03:35,177
because we try not to look
  so far into the future.

1578
01:03:35,210 --> 01:03:38,614
Right now, everything is
 fully redundant on Spitzer,

1579
01:03:38,647 --> 01:03:40,616
all the, most of the
 parts on Spitzer,

1580
01:03:40,649 --> 01:03:42,351
because it's a
 telescope in space,

1581
01:03:42,384 --> 01:03:44,119
and if it breaks
  you can't fix it,

1582
01:03:44,152 --> 01:03:45,287
so we have two of things, like

1583
01:03:45,320 --> 01:03:46,655
there's two star
 trackers for instance.

1584
01:03:46,688 --> 01:03:48,858
The only thing we
  have one of are

1585
01:03:48,891 --> 01:03:51,460
the arrays and the
  mirror, obviously.

1586
01:03:52,761 --> 01:03:55,097
I think Spitzer could
 take useful data

1587
01:03:55,130 --> 01:03:59,635
out to 2021, for
  sure... possibly.

1588
01:03:59,668 --> 01:04:00,970
It could go further than that,

1589
01:04:01,003 --> 01:04:02,471
but it'd be taking
 less and less data,

1590
01:04:02,504 --> 01:04:04,607
and of course sooner or later
 something's going to break.

1591
01:04:04,640 --> 01:04:05,975
If I had to bet on
  what would break,

1592
01:04:06,008 --> 01:04:07,243
it would be the reaction wheels.

1593
01:04:07,276 --> 01:04:08,978
The things that help
 drive Spitzer around

1594
01:04:09,011 --> 01:04:09,979
because they're spinning parts,

1595
01:04:10,012 --> 01:04:11,647
they're continuously spinning,

1596
01:04:11,680 --> 01:04:13,816
and we're way beyond
 warranty on those.

1597
01:04:13,849 --> 01:04:15,284
[crowd chuckles]

1598
01:04:15,317 --> 01:04:17,653
Yeah, the only good thing,
 is I think we got a good set,

1599
01:04:17,686 --> 01:04:19,622
so we bought 'em on a Wednesday
or something and didn't

1600
01:04:19,655 --> 01:04:21,156
do bargain in basement.
[audience laughs]

1601
01:04:21,189 --> 01:04:24,159
Which speaks very well to
  project management at JPL,

1602
01:04:24,192 --> 01:04:25,027
I might add.

1603
01:04:26,662 --> 01:04:29,532
>> Thank you very much.
  >> Carey: You're welcome.

1604
01:04:30,732 --> 01:04:33,435
>> Hi, you mentioned
 about the redshift,

1605
01:04:33,468 --> 01:04:34,970
>> Carey: Yes.
 >> Yeah, so...

1606
01:04:35,003 --> 01:04:37,306
how do you determine
 whether the celestial object

1607
01:04:37,339 --> 01:04:40,943
was starting with some
 wavelength or is it,

1608
01:04:40,976 --> 01:04:45,314
was it initially red and not
 white, so to have shifted?

1609
01:04:45,347 --> 01:04:47,383
>> So, you make the
 assumption that when

1610
01:04:47,416 --> 01:04:51,621
you look at the distant
  galaxies that they have...

1611
01:04:53,488 --> 01:04:56,025
Emission, like a spectral
  energy distribution

1612
01:04:56,058 --> 01:04:58,661
that the light coming, it
 is a functional wavelength,

1613
01:04:58,694 --> 01:05:01,230
looks like a galaxy.

1614
01:05:01,263 --> 01:05:03,165
Okay, and then you
 try to fit different,

1615
01:05:03,198 --> 01:05:04,400
and there are different ways.

1616
01:05:04,433 --> 01:05:05,901
So you can have galaxies
that don't have dust,

1617
01:05:05,934 --> 01:05:08,537
galaxies that have dust,
  galaxies that form stars,

1618
01:05:08,570 --> 01:05:11,974
so the things that have dust
 or form stars may be redder.

1619
01:05:12,007 --> 01:05:13,776
And then you fit
  that to the data,

1620
01:05:13,809 --> 01:05:15,077
and then, basically,
 what you have to do

1621
01:05:15,110 --> 01:05:16,779
is see if you can get a good fit

1622
01:05:16,812 --> 01:05:19,214
by progressively shifting
  the different models

1623
01:05:19,247 --> 01:05:22,351
back and forth with redshift
 until you get to one

1624
01:05:22,384 --> 01:05:24,420
that fits very well,
 and that was done.

1625
01:05:24,453 --> 01:05:26,121
The other thing that
Spitzer allows you to do

1626
01:05:26,154 --> 01:05:29,258
is rule out nearby,
 but dusty galaxies

1627
01:05:29,291 --> 01:05:32,828
which give you a sort of
 similar shape in the visible,

1628
01:05:32,861 --> 01:05:34,396
because you don't see the
  short wavelength light

1629
01:05:34,429 --> 01:05:36,398
'cause it gets blocked out.

1630
01:05:36,431 --> 01:05:39,234
So it could either
 be dust or redshift.

1631
01:05:39,267 --> 01:05:40,736
Does that help, does
  that answer you question?

1632
01:05:40,769 --> 01:05:45,140
>> Yes, so, is that based on
 the prior observations, right,

1633
01:05:45,173 --> 01:05:47,309
of the galaxies and
 what wavelengths

1634
01:05:47,342 --> 01:05:48,844
do they generally emit?

1635
01:05:48,877 --> 01:05:50,746
>> Yes, that's right,
 so it's based on

1636
01:05:51,680 --> 01:05:54,083
measurements of nearby galaxies

1637
01:05:54,116 --> 01:05:56,518
and then also modeling
based on what, you know,

1638
01:05:56,551 --> 01:05:58,921
we know what the constituents
 of galaxies should be.

1639
01:05:58,954 --> 01:06:01,123
So then you can put those
 together in a model as well.

1640
01:06:01,156 --> 01:06:04,093
So it's a combination
 of, use models,

1641
01:06:04,126 --> 01:06:05,861
but they're informed
by observations

1642
01:06:05,894 --> 01:06:07,529
of nearby
objects, yes.

1643
01:06:07,562 --> 01:06:12,568
>> Okay... my second question
 is, you use this spectroscopy

1644
01:06:13,969 --> 01:06:16,338
to find out the chemical
 composition as well, right?

1645
01:06:16,371 --> 01:06:21,377
>> Yes, well, when Spitzer had
 a working spectrograph we did.

1646
01:06:22,778 --> 01:06:24,813
Hubble still does that, so,
 actually that galaxy I showed

1647
01:06:24,846 --> 01:06:28,150
was spectroscopically
 confirmed by Hubble

1648
01:06:28,183 --> 01:06:30,019
because they were able to
  actually look for lines

1649
01:06:30,052 --> 01:06:31,887
that they knew where
 they should be at,

1650
01:06:31,920 --> 01:06:32,955
and then they were
  able to measure

1651
01:06:32,988 --> 01:06:35,324
the redshift directly from that.

1652
01:06:35,357 --> 01:06:38,260
>> Okay, so, in case
 there is a chemical

1653
01:06:38,293 --> 01:06:41,397
which is not known to us,
  like this spectroscopy,

1654
01:06:41,430 --> 01:06:43,499
we don't about some chemical...

1655
01:06:43,532 --> 01:06:45,768
so it is possible that
 we can extrapolate

1656
01:06:45,801 --> 01:06:48,504
from the power of observations
 and what we observe now,

1657
01:06:48,537 --> 01:06:51,140
to find out that might
 be a new chemical

1658
01:06:51,173 --> 01:06:53,242
which we are seeing
 in the spectroscopy.

1659
01:06:53,275 --> 01:06:54,777
>> Yeah, that's
 certainly possible,

1660
01:06:54,810 --> 01:06:56,211
with the spectroscopy here,

1661
01:06:56,244 --> 01:06:58,180
it usually doesn't have
high enough resolution

1662
01:06:58,213 --> 01:07:01,016
to be able to see things
we don't understand.

1663
01:07:01,049 --> 01:07:02,718
It, longer wavelengths
 than the radio

1664
01:07:02,751 --> 01:07:04,353
and the sub-millimeter,
in particular.

1665
01:07:04,386 --> 01:07:07,256
There are a lot of lines
 that are unidentified still

1666
01:07:07,289 --> 01:07:09,591
and chemists are working
very hard on those.

1667
01:07:09,624 --> 01:07:11,727
>> Inquirer: Thank you.
>> You're welcome.

1668
01:07:15,263 --> 01:07:16,732
>> Would there be...

1669
01:07:18,433 --> 01:07:22,538
Is Mars atmosphere strong
  enough to have life?

1670
01:07:22,571 --> 01:07:26,375
Because, like, the gulleys...

1671
01:07:28,310 --> 01:07:31,480
they could have been carved
 by water because, like...

1672
01:07:33,048 --> 01:07:34,650
>> Right, so you might
 know more about Mars

1673
01:07:34,683 --> 01:07:36,452
than I do actually
 because I don't study

1674
01:07:36,485 --> 01:07:39,288
our solar system, so, my
  understanding is that Mars

1675
01:07:39,321 --> 01:07:41,824
had a more
 significant atmosphere

1676
01:07:41,857 --> 01:07:44,126
and most of that is left
 because the density of Mars

1677
01:07:44,159 --> 01:07:47,863
is too low to hold a very
  significant atmosphere.

1678
01:07:47,896 --> 01:07:49,231
So, there was
 probably water on it,

1679
01:07:49,264 --> 01:07:50,633
which is what we're seeing.

1680
01:07:51,967 --> 01:07:53,869
And some of the planets
on the TRAPPIST system

1681
01:07:53,902 --> 01:07:55,370
have similar densities to Mars,

1682
01:07:55,403 --> 01:07:57,639
so they might also
  be very Mars-like,

1683
01:07:57,672 --> 01:08:01,643
or they could also
  have smaller...

1684
01:08:01,676 --> 01:08:03,212
they could have fairly
 significant cores,

1685
01:08:03,245 --> 01:08:06,482
with a much larger envelope
 and atmosphere still,

1686
01:08:06,515 --> 01:08:08,517
and we don't know the
 answer to that yet.

1687
01:08:08,550 --> 01:08:10,018
So, they could be
very Mars-like,

1688
01:08:10,051 --> 01:08:11,587
like you've mentioned.

1689
01:08:12,821 --> 01:08:15,624
>> And my second question is...

1690
01:08:15,657 --> 01:08:18,760
I've heard that in
2020 they're gonna make

1691
01:08:18,793 --> 01:08:23,799
a telescope that can
 see past several...

1692
01:08:31,139 --> 01:08:34,810
Galaxies, like, I can't
think of the name...

1693
01:08:36,244 --> 01:08:37,746
>> Are you thinking of
  the James Webb Telescope?

1694
01:08:37,779 --> 01:08:39,715
Because the James Webb Telescope

1695
01:08:39,748 --> 01:08:41,350
is a much larger
collecting area.

1696
01:08:41,383 --> 01:08:44,653
Will it be able to see even
 farther back in the universe

1697
01:08:44,686 --> 01:08:47,289
than the combination
 of Spitzer and Hubble?

1698
01:08:47,322 --> 01:08:48,524
And that's certainly true,

1699
01:08:48,557 --> 01:08:50,859
one of the things
  we will have to,

1700
01:08:50,892 --> 01:08:52,528
one of the things that
Webb was designed to do

1701
01:08:52,561 --> 01:08:55,063
was to go back and look at
  the epic of first stars.

1702
01:08:55,096 --> 01:08:56,798
And I think from
what we understand

1703
01:08:56,831 --> 01:08:57,899
with Spitzer and Hubble

1704
01:08:57,932 --> 01:09:00,335
is that stars formed a lot
  earlier in the universe

1705
01:09:00,368 --> 01:09:01,870
than we had anticipated,

1706
01:09:01,903 --> 01:09:04,873
so Webb may not actually be
 able to see the first stars,

1707
01:09:04,906 --> 01:09:07,843
but it will see a lot of
 the very earliest galaxies.

1708
01:09:09,110 --> 01:09:10,513
>> Thank you.
  _ [Carey] You're welcome.

1709
01:09:12,981 --> 01:09:14,416
>> Hi, thanks for the talk.

1710
01:09:14,449 --> 01:09:16,318
My question is actually very
 similar to his question,

1711
01:09:16,351 --> 01:09:19,188
I was wondering
  in what ways will,

1712
01:09:19,221 --> 01:09:20,956
is Spitzer gonna be a precursor

1713
01:09:20,989 --> 01:09:22,624
for James Webb Space Telescope,

1714
01:09:22,657 --> 01:09:24,259
and how can it
 inform that mission?

1715
01:09:24,292 --> 01:09:25,427
>> Yeah, it's a good question.

1716
01:09:25,460 --> 01:09:26,929
And I think the combining,

1717
01:09:26,962 --> 01:09:31,233
in terms of understanding
 the high redshift universe,

1718
01:09:31,266 --> 01:09:33,402
the combination of
  Hubble and Spitzer

1719
01:09:33,435 --> 01:09:37,406
has already told us that Webb
 will not see the first stars.

1720
01:09:37,439 --> 01:09:38,740
The combination's
  also telling us

1721
01:09:38,773 --> 01:09:41,543
some of the objects that
Webb should look at,

1722
01:09:41,576 --> 01:09:42,878
some of the most
distant galaxies

1723
01:09:42,911 --> 01:09:44,680
that have already
  been identified.

1724
01:09:44,713 --> 01:09:48,116
So those are the first
  targets that Webb will use

1725
01:09:48,149 --> 01:09:51,186
to, with its spectrographs
  to disperse the light

1726
01:09:51,219 --> 01:09:52,721
and really characterize them.

1727
01:09:52,754 --> 01:09:54,790
So, Webb will give
 us an understanding

1728
01:09:54,823 --> 01:09:57,493
of the star formation rate,

1729
01:09:58,660 --> 01:10:01,496
and how metal and rich
 those galaxies are,

1730
01:10:01,529 --> 01:10:03,298
which will tell us something
 about if there were

1731
01:10:03,331 --> 01:10:05,801
previous episodes of
star formation in those.

1732
01:10:05,834 --> 01:10:07,536
Which at some point there
  won't be any, right?

1733
01:10:07,569 --> 01:10:11,139
You're gonna see just that
first primordial star formation,

1734
01:10:11,172 --> 01:10:13,041
but Webb will be able
 to actually measure

1735
01:10:13,074 --> 01:10:15,911
the metal content in the
gas of those galaxies

1736
01:10:15,944 --> 01:10:17,947
and that will be very
 powerful, I think.

1737
01:10:19,214 --> 01:10:20,349
>> Thank you.
  >> Carey: You're welcome.

1738
01:10:22,550 --> 01:10:24,086
>> If you could indulge
one other question,

1739
01:10:24,119 --> 01:10:25,354
>> Carey: Absolutely.

1740
01:10:25,387 --> 01:10:26,955
>> The Mars topic made
 me think of something.

1741
01:10:26,988 --> 01:10:30,826
So, Mars lost a lot
 of it's atmosphere

1742
01:10:30,859 --> 01:10:34,896
because the core freezing
  out lost the magnetism,

1743
01:10:34,929 --> 01:10:38,100
on the TRAPPIST system
  for the Mars-like objects,

1744
01:10:38,133 --> 01:10:40,902
is it possible, is
 the resolution to see

1745
01:10:40,935 --> 01:10:45,073
or to infer magnetic
fields from Zeeman lines

1746
01:10:45,106 --> 01:10:48,377
or is that not feasible?

1747
01:10:48,410 --> 01:10:52,314
>> I don't think that'll be
 feasible with any technology

1748
01:10:52,347 --> 01:10:55,851
that can be done
 in...in, uh, yeah...

1749
01:10:55,884 --> 01:10:58,754
I think that's a
 very hard observation

1750
01:10:58,787 --> 01:11:02,190
to see the Zeeman splitting,
 there's not much signal.

1751
01:11:02,223 --> 01:11:05,995
Remember the transits are 1%

1752
01:11:07,095 --> 01:11:08,630
and what you're gonna
 talk about then,

1753
01:11:08,663 --> 01:11:12,334
is looking at the
  atmospheric constituents,

1754
01:11:12,367 --> 01:11:17,272
so you figure the atmosphere
 is at most 1/100th of that,

1755
01:11:17,305 --> 01:11:19,841
so now you're down
  another factor of hundred

1756
01:11:19,874 --> 01:11:21,843
and then you have to have
  enough signal to noise

1757
01:11:21,876 --> 01:11:24,212
and a very narrow
  wavelength range,

1758
01:11:24,245 --> 01:11:26,081
to be able to resolve the lines.

1759
01:11:26,114 --> 01:11:27,716
So, I think, you'd
  need an enormous

1760
01:11:27,749 --> 01:11:28,950
collecting area to do that.

1761
01:11:28,983 --> 01:11:30,119
I think that's...

1762
01:11:32,220 --> 01:11:34,222
You would need a
 gigantic telescope,

1763
01:11:34,255 --> 01:11:35,824
[laughter]

1764
01:11:35,857 --> 01:11:37,893
I can't even figure out
how big the telescope

1765
01:11:37,926 --> 01:11:39,728
would need to be, which
is what you're asking.

1766
01:11:39,761 --> 01:11:42,364
So, I think it's, that'd be
 really far in the future.

1767
01:11:42,397 --> 01:11:45,000
I'd be very happy
  if, with these,

1768
01:11:45,033 --> 01:11:50,005
we were able to actually get
 a measurement of constituents,

1769
01:11:50,038 --> 01:11:52,007
chemical constituents
 in the atmosphere.

1770
01:11:52,040 --> 01:11:54,143
If we're able to
 see a low resolution

1771
01:11:55,310 --> 01:11:58,714
specter of the
 atmosphere in transit

1772
01:11:58,747 --> 01:12:01,583
that showed us a dipped
for methane or CO2,

1773
01:12:01,616 --> 01:12:03,385
could tell us something
about, what those...

1774
01:12:03,418 --> 01:12:04,953
First all, if there is
 an atmosphere right?

1775
01:12:04,986 --> 01:12:06,822
That's the first thing,
and then the second,

1776
01:12:06,855 --> 01:12:09,057
what would that
  atmosphere be composed of?

1777
01:12:09,090 --> 01:12:11,760
And I know based on
 work people have done

1778
01:12:11,793 --> 01:12:14,963
in planning for observations
 with James Webb of TRAPPIST

1779
01:12:14,996 --> 01:12:18,100
and a couple other systems
 that that's entirely feasible.

1780
01:12:18,133 --> 01:12:21,470
It just, in a couple years,
 we'll have an answer to that

1781
01:12:21,503 --> 01:12:22,404
which I think is real exciting,

1782
01:12:22,437 --> 01:12:24,239
because we know what to look at

1783
01:12:24,272 --> 01:12:26,141
and we have a
 telescope very soon

1784
01:12:26,174 --> 01:12:28,243
that will allow us to
 do that, so, you know,

1785
01:12:28,276 --> 01:12:29,745
wait a couple of years
  and somebody will give you

1786
01:12:29,778 --> 01:12:33,415
a von Kármán Lecture
 in 2022, hopefully,

1787
01:12:33,448 --> 01:12:35,517
and we'll have some
 of those answers.

1788
01:12:35,550 --> 01:12:39,388
>> Would any of the large
 Earth proposed, large scale

1789
01:12:39,421 --> 01:12:41,490
space station would
  ferrometers be capable of

1790
01:12:41,523 --> 01:12:44,259
getting down to that
detection level, or not?

1791
01:12:44,292 --> 01:12:45,660
>> It's not a question
 of resolution,

1792
01:12:45,693 --> 01:12:47,629
it's a question of
  collecting area, I think.

1793
01:12:47,662 --> 01:12:50,632
For things like the
 Zeeman splitting.

1794
01:12:50,665 --> 01:12:55,404
So you want a massive single
 aperture and I think...

1795
01:12:57,105 --> 01:12:59,908
my gut is telling
  me that, what you,

1796
01:12:59,941 --> 01:13:01,643
for that particular
 experiment you need something

1797
01:13:01,676 --> 01:13:04,513
way beyond anything that
we'd be able to assemble

1798
01:13:04,546 --> 01:13:06,281
in the next 20 years.

1799
01:13:06,314 --> 01:13:07,816
>> Inquirer: Thanks.
 >> You're welcome.

1800
01:13:09,083 --> 01:13:10,652
>> I have a question about,

1801
01:13:10,685 --> 01:13:13,321
since you've reached
 that far in the galaxy

1802
01:13:13,354 --> 01:13:16,057
what about the dark matter?

1803
01:13:16,090 --> 01:13:19,828
Have you ever considered,
 since you talked about masses

1804
01:13:19,861 --> 01:13:23,866
and taking that [mumbles]
  the controversial...

1805
01:13:26,234 --> 01:13:29,638
Aspect of dark matter
 and they're trying

1806
01:13:29,671 --> 01:13:32,140
right now to change
 the equation.

1807
01:13:32,173 --> 01:13:34,309
>> Carey: Yeah, for the...
 >> Have you looked at that?

1808
01:13:34,342 --> 01:13:37,379
>> Not for, with Spitzer,
  not for our own Milky Way,

1809
01:13:39,080 --> 01:13:41,016
I know for external galaxies

1810
01:13:41,049 --> 01:13:42,584
there's been a lot
  of observations

1811
01:13:42,617 --> 01:13:46,254
in conjunction with either
  ground based spectrographs

1812
01:13:46,287 --> 01:13:49,291
or Hubble to get some measure
 of the velocity dispersion.

1813
01:13:49,324 --> 01:13:50,992
Spitzer gives you very well,

1814
01:13:51,025 --> 01:13:54,796
the visible mass
 density of the galaxy.

1815
01:13:54,829 --> 01:13:57,566
So the combination of we're
 getting rotation curves

1816
01:13:57,599 --> 01:13:59,734
and visible masses
  help to determine

1817
01:13:59,767 --> 01:14:04,439
what the dark matter halos are,
for fairly nearby galaxies.

1818
01:14:04,472 --> 01:14:06,174
So, and you know...

1819
01:14:06,207 --> 01:14:10,412
>> I was also wondering, the
 Webb might be able to actually

1820
01:14:11,379 --> 01:14:14,783
look at that more accurately?

1821
01:14:14,816 --> 01:14:18,353
>> Yeah, actually Webb will be
 able to do that as well, yeah.

1822
01:14:18,386 --> 01:14:21,723
>> Okay, I want to make
a final comment here

1823
01:14:21,756 --> 01:14:25,060
about the budgeting
 and thing with that.

1824
01:14:25,093 --> 01:14:29,164
We had, for the
 Magellan Spacecraft,

1825
01:14:29,197 --> 01:14:31,666
we had the design for one year

1826
01:14:31,699 --> 01:14:34,369
and that were to
 operate for 40 years

1827
01:14:34,402 --> 01:14:38,707
and they cut the
 funding after that,

1828
01:14:38,740 --> 01:14:41,643
although it could operate
  for much longer than that.

1829
01:14:43,511 --> 01:14:47,182
Unfortunately, people who make
 decision to cut the funding

1830
01:14:47,215 --> 01:14:50,252
are not the one who
actually do the work...

1831
01:14:50,285 --> 01:14:52,587
>> Yeah, no that's
  a fair comment.

1832
01:14:52,620 --> 01:14:53,822
I think there's a
 lot of good science

1833
01:14:53,855 --> 01:14:55,056
that could continue to be done

1834
01:14:55,089 --> 01:14:57,125
with a lot of
 existing facilities,

1835
01:14:57,158 --> 01:14:58,627
and it's just a
 question of priority.

1836
01:14:58,660 --> 01:15:01,429
So, I understand, the folks
 who make those decisions

1837
01:15:01,462 --> 01:15:04,199
actually have a really
  hard job in prioritizing.

1838
01:15:05,300 --> 01:15:07,402
[inaudible]

1839
01:15:07,435 --> 01:15:10,839
Oh yeah, let me put my
 glasses on... okay...

1840
01:15:10,872 --> 01:15:13,075
So we have a couple
 from the web, I guess.

1841
01:15:14,876 --> 01:15:18,046
So Hassid asked, "Are
  there any other telescopes

1842
01:15:18,079 --> 01:15:20,782
"working infrared in space?"

1843
01:15:22,517 --> 01:15:25,320
Well James Webb will
 be working very soon.

1844
01:15:25,353 --> 01:15:28,957
There's the WISE mission, which
is actually doing a survey,

1845
01:15:28,990 --> 01:15:30,825
it's in it's extended mission,

1846
01:15:30,858 --> 01:15:33,161
so it does a, it's
 a survey of the sky

1847
01:15:33,194 --> 01:15:34,896
and it's operating
 in bands very close

1848
01:15:34,929 --> 01:15:37,532
to what IRAC is doing
 now for Spitzer,

1849
01:15:37,565 --> 01:15:38,767
so it's very complimentary,

1850
01:15:38,800 --> 01:15:40,835
and one of the things
WISE is doing actually,

1851
01:15:40,868 --> 01:15:43,038
is looking for
 near-Earth objects.

1852
01:15:43,071 --> 01:15:45,006
Near-Earth asteroids and comets

1853
01:15:45,039 --> 01:15:47,309
using the infrared,
 so that's one.

1854
01:15:47,342 --> 01:15:51,846
And then, not in space, but
 very close to space is Sophia,

1855
01:15:51,879 --> 01:15:54,215
which has a huge
  compliment of instruments

1856
01:15:54,248 --> 01:15:57,218
because they can change them
 out because it's on a plane.

1857
01:15:57,251 --> 01:15:59,421
So, that's another
 telescope that's working in,

1858
01:15:59,454 --> 01:16:01,923
sort of near, space
 in the infrared.

1859
01:16:01,956 --> 01:16:03,792
Okay, and then I have
 one from Will here,

1860
01:16:03,825 --> 01:16:05,761
Okay, he asked, "How
 much gas is left?

1861
01:16:07,362 --> 01:16:08,630
"Could you line
  up the telescopes

1862
01:16:08,663 --> 01:16:11,232
"with CubeSats to make
 communication link?"

1863
01:16:11,265 --> 01:16:13,268
Those are very good questions.

1864
01:16:13,301 --> 01:16:15,403
So, I think the first
 one is about the gas,

1865
01:16:15,436 --> 01:16:16,771
the reaction gas.

1866
01:16:16,804 --> 01:16:18,974
So Spitzer has a
  tank of nitrogen,

1867
01:16:19,007 --> 01:16:22,010
which is used to dump momentum
 from the reaction wheels.

1868
01:16:22,043 --> 01:16:26,114
We had 15 kilograms to start,
 we have more than seven now.

1869
01:16:26,147 --> 01:16:28,350
So we have plenty
  of gas to do that.

1870
01:16:28,383 --> 01:16:30,885
Otherwise, we move entirely
 on the reaction wheels.

1871
01:16:30,918 --> 01:16:32,954
So the big thing with Spitzer is

1872
01:16:32,987 --> 01:16:35,290
if a reaction wheel breaks,
 then it's harder to move.

1873
01:16:35,323 --> 01:16:39,427
We have four, we could
 operate on three very easily,

1874
01:16:39,460 --> 01:16:42,364
two would make engineers do
 things they don't want to do,

1875
01:16:42,397 --> 01:16:44,733
and we'd not be
  able to afford it.

1876
01:16:44,766 --> 01:16:47,235
Linking up with CubeSats to
 make the communications link.

1877
01:16:47,268 --> 01:16:48,737
I think the answer
  to that is no.

1878
01:16:48,770 --> 01:16:50,672
Because the CubeSats
 are too small

1879
01:16:50,705 --> 01:16:53,575
to provide enough collecting
 area to be a repeater.

1880
01:16:53,608 --> 01:16:55,710
I mean, because you
 would need something

1881
01:16:55,743 --> 01:16:58,446
with as much power as
 probably the Spitzer,

1882
01:16:58,479 --> 01:17:00,015
or a high gain
 antenna to do that,

1883
01:17:00,048 --> 01:17:01,516
and I don't think
  you could fit that

1884
01:17:01,549 --> 01:17:04,319
in a CubeSat form factor, but
 that's an interesting idea.

1885
01:17:04,352 --> 01:17:05,687
Okay, so I think those
 are from the web,

1886
01:17:05,720 --> 01:17:06,921
and you had a question sir?

1887
01:17:06,954 --> 01:17:08,189
>> Yes, first of all,
 I'd just like to say

1888
01:17:08,222 --> 01:17:09,557
thank you very much for
your time this evening,

1889
01:17:09,590 --> 01:17:11,159
it's been very, very
 informational...

1890
01:17:11,192 --> 01:17:12,360
>> Carey: Thank you.

1891
01:17:12,393 --> 01:17:13,795
>> One question that
 I've taken away,

1892
01:17:13,828 --> 01:17:15,597
is so far with the discovery
 of all the exoplanets

1893
01:17:15,630 --> 01:17:18,233
that Spitzer's of
course been involved in,

1894
01:17:18,266 --> 01:17:20,502
am I to infer from
this that we're finding

1895
01:17:20,535 --> 01:17:23,271
an extraordinarily
  high percentage

1896
01:17:23,304 --> 01:17:24,773
that are actually
  tidally locked?

1897
01:17:24,806 --> 01:17:27,509
And if so, is there
 a reason for that,

1898
01:17:27,542 --> 01:17:29,577
that they've been
  able to ascertain?

1899
01:17:29,610 --> 01:17:31,713
>> So, the ones tidally locked

1900
01:17:31,746 --> 01:17:34,916
are because of
 proximity to the star.

1901
01:17:34,949 --> 01:17:38,987
It's just the, it's a
 question of orbital dynamics.

1902
01:17:39,020 --> 01:17:41,423
So, it's a selection
 effect, I think,

1903
01:17:41,456 --> 01:17:45,460
in that the planets
 that are orbiting...

1904
01:17:45,493 --> 01:17:48,630
closer in, are easier to
observe if the geometry's right

1905
01:17:48,663 --> 01:17:50,632
from transiting and
 they're also the ones

1906
01:17:50,665 --> 01:17:52,534
that we can
 characterize the best.

1907
01:17:52,567 --> 01:17:55,837
So, you see this
  population preferentially.

1908
01:17:57,305 --> 01:18:00,975
I'm blanking on what
  Kepler's shown in terms of

1909
01:18:01,008 --> 01:18:04,112
total planetary statistics
  about the distribution.

1910
01:18:04,145 --> 01:18:06,414
I mean, the idea of these
  in-close, hot Jupiters

1911
01:18:06,447 --> 01:18:09,050
was something that people
  who modeled systems

1912
01:18:09,083 --> 01:18:12,654
before they were
 discovered hadn't expected.

1913
01:18:12,687 --> 01:18:14,823
Just because dynamically
you had to figure out

1914
01:18:14,856 --> 01:18:17,759
how to get them there,
but now I think they've,

1915
01:18:17,792 --> 01:18:19,961
the models accommodate
 this very well.

1916
01:18:19,994 --> 01:18:22,530
But I think really
 when we focus on it,

1917
01:18:22,563 --> 01:18:23,965
it's really just a
  selection effect.

1918
01:18:23,998 --> 01:18:25,300
It's not that these
 are more prevalent,

1919
01:18:25,333 --> 01:18:26,735
but they're very interesting.

1920
01:18:26,768 --> 01:18:27,936
>> Inquirer: Got ya.
 >> Okay.

1921
01:18:27,969 --> 01:18:28,737
>> Inquirer: Thank
  you very much.

1922
01:18:28,770 --> 01:18:29,504
>> You're welcome.

1923
01:18:33,241 --> 01:18:35,110
Well, thank you for your time.