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Marc Kuchner: I don't know--when I was growing up, there was no such thing as planets around

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other stars. If you were to talk about it at a scientific meeting, people would laugh at you.

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Not that I was talking at scientific meetings when I was in high school, but

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so I'm told.
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Jennifer Wiseman: Planets are very small compared

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to the stars that they orbit. They're also very dim.

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Marc Kuchner: For example, the Earth is ten billion times fainter

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than the Sun--ten billion times fainter.
Jennifer Wiseman: It's kind of like

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trying to see a firefly next to a lighthouse.

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It gets lost in the glare.

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Marc Kuchner: The Hubble Space Telescope takes pictures of nearby

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stars and uses a special tool called a coronagraph

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and the coronagraph blocks out the light from the star.

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Aki Roberge: It's a fancy way of putting your thumb over the star, basically, so you can see

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something faint that is right next to it.

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Jennifer Wiseman: We can also use Hubble and other telescopes to study

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regions where we think planets might be forming.

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Marc Kuchner: We see in images from Hubble, we see these rings of dust

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around nearby stars.
Aki Roberge: Well what I observe

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with Hubble are those disks. Those disks of gas

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and dust around the young stars, in which we think the dust grains

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are starting to clump together and build up into pebbles,

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rocks, asteroids, comets, Earths.

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Jennifer Wiseman: We're finding baby solar systems by using

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Hubble and other telescopes, including sort of ground-based radio telescopes

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that can peer into these disks around stars and

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see young planets or regions where young planetary systems

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are forming.
Aki Roberge: The study of exoplanets is

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only a little over 15 years old.
Marc Kuchner: We've discovered more

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than 400 extrasolar planets now.

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Aki Roberge: You know, we're still just beginning to

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understand how the processes that formed

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our own solar system, also formed these really diverse

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types of planets. I think the thing that excites me

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most is just the basic discovery of what

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exists. You know, what's out there. Waterworlds, carbon planets?

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It sounds like science fiction, but not really.

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Not anymore.
Marc Kuchner: Why did life arise on

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Earth instead of somewhere else?

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I mean if there's another planet that could have life on it,

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why aren't we there?
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