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welcome to the Space Telescope public

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lecture series uh tonight's talk the

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universe of Dante Alighieri from the

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descendant of Dante Alighieri spirello

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disrego allegieri

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I am your host uh Dr Frank Summers from

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The Office of Public Outreach at the

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Space Telescope Science Institute and as

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always I want to thank our wonderful

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tech team Thomas marufu and Grant

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Justice

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I will also note that management has

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decided that the Space Telescope public

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lecture series will continue to be

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online only through the rest of 22 2022

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and also during 2023 so for the

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foreseeable future we will continue to

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be online only and we will not have the

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in-person uh presentations in the sdsci

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auditorium

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our upcoming talks and next month on

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November 1st Stephanie lamasa from Space

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Telescope we'll talk about black holes

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how do we see that which gives off no

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light

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on December 6th we will do high energy

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astronomy with the Swift Observatory and

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that will feature Steve Kirby from the

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Penn State University

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on January 10th we will have a talk but

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I have not scheduled it so as usual I

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put in my placeholder a fascinating

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topic by an insightful speaker

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uh when we do have that uh talk booked

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www.stsci.edu public hyphen lectures uh

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on that webpage you will find a link to

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our webcasts uh both our YouTube

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playlist and our stsci webcast archives

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as well as the

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um email list where you can put in your

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email address and hit the Subscribe

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button

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also on our website we have the list of

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the upcoming lectures and if you click

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on one of those lectures you will get

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the details the of uh the description

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and the speaker as well as after it's

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been recorded links to the stsci webcast

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and the YouTube webcast

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uh for announcements um as I said sign

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up at the website you can also subscribe

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to our YouTube channel youtube.com

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Hubble Space Telescope that's all one

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word Hubble Space Telescope uh you will

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get new video notices and reminders of

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Live Events such as this

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finally if you have comments or

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questions you can send them to the email

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address public lecture all one word at

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furthermore you can follow us on social

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media we have social media channels for

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the Hubble Space Telescope for the web

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Space Telescope and for the Space

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Telescope Science Institute and you can

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find those on Facebook Twitter Youtube

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and Instagram I myself do a very minor

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amount of stuff on social media on

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Facebook and Twitter as Dr Frank Summers

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and now our news from the universe for

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October 2022.

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our story tonight a tarantula caught by

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this is the large magellanic cloud and

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it is a dwarf Galaxy that is a satellite

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Galaxy of our own Milky Way galaxy and

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you may say all right it's a dwarf

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Galaxy it's kind of small and everything

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but

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it has the largest star-foring region

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anywhere in the local group

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this star-form region called the

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tarantula nebula is larger than any

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star-forming region in the Milky Way

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galaxy or in the Andromeda galaxy there

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is an incredible amount of star

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formation going on here and of course

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astronomers have studied it many many

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many many many times

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we have studied it with the Hubble Space

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Telescope and here is an image from I

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think this is 2012 from Hubble this is

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both a little bit of visible light and a

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good amount of the near infrared from

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Hubble and you can see these bubbles uh

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created here in the the structure by

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newborn stars and the winds and the

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Supernova explosions that can happen in

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here there's a huge cluster of stars in

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here whoops I didn't mean to hit that a

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huge cluster of stars in here called

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r136 that's sort of the core of the

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tarantula nebula uh has also been

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studied

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um with the Spitzer Space Telescope now

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remember this Hubble is done invisible

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and a good amount of near infrared so if

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I go to the Spitzer Space Telescope

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which is infrared

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it doesn't look that different

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um uh because we have a good amount of

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infrared in the Hubble image but you can

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see this green material here if I blink

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back to the Hubble that corresponds

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pretty well to the materials seen in

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Spitzer of course Hubble has a much

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finer resolution than Spitzer does and

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sees more detail

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but if you want even more detail well

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the James Webb Space Telescope has

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looked at the tarantula nebula now and

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it took an image in this region here of

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the tarantula nebula a region that's

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centered on that star cluster called

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r136 that I mentioned before

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and you can see just from this that this

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uh that web is such such a higher it's a

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Quantum Leap in resolution over Spitzer

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and let's bring that image full screen

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and you can see all of the rich detail

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we have here in the tarantula nebula

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from web

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but this doesn't actually do it justice

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because this image is about one-fifth or

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one-sixth scale that you're seeing it uh

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on here so let me zoom into the region

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around that star cluster and give you a

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somewhat full resolution view of it now

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this is of course going to be modified

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by my computer to uh out to the the

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webcast onto your computer and so you're

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not probably not going to see all the

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incredible detail here but just look at

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all the stars we're seeing here in r136

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all right and if we go to a region

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that's got a nebula structure well

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that's really cool too and you get

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incredible detail so we're trying to

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illustrate for you the detail that web

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is able to see with a six and a half

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meter mirror looking in the infrared

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all right so that's sort of be expected

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we knew Webb was going to be a Quantum

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Leap over Spitzer but how does it

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compare to Hubble well this is one of

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the few images where Hubble has a lot of

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infrared

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um so it's actually a relatively Apples

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to Apples comparison of Hubble versus

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web all right and so the on the left is

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a Hubble image that I believe is from

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2016 and on the right is the brand new

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web image of the tarantula nebula

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um and you can see in in detail just

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from this large-scale view that uh Webb

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has a SL has a just a bit more

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resolution okay it's about a factor of

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one and a half factor of two resolution

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that's better better than Hubble but

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we're going to zoom in on this lower

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left region here um and show you a

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little more detail right okay so here's

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the Hubble image and I'm going to be

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able to Blink back and forth and here is

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the web image

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okay and Hubble

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and web and there you can see that that

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there's just that much more sharpness in

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the web image than there is in the

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Hubble image and also in the Hubble

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image we see a lot of this dark gas down

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here okay this dark gas that um is

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opaque to wavelengths that Hubble

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observes but when you go further into

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the infrared you actually see through it

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and you see more detail and structure of

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what's Happening inside these gas clouds

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all right and this kind of comparison is

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something that you know I haven't done

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much I don't haven't done much before

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I've done I've done it with a bunch of

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things but it's hard to get you know

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images that are reasonably well to

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compare

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um but it brings up questions in people

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and people ask me all right well which

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is better Hubble or web all right and I

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usually respond to that by saying all

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right well which is better an SUV or a

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sports car right now if you're going out

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to a construction site or you want to go

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off-roading or you want to you know haul

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stuff you want that SUV and if you're

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going out onto the highway you want to

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Zoop around you want to take those tight

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curves well you want that sports car all

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right the same thing is going on here if

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you're looking in visible light you want

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Hubble if you're looking at infrared

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light you want James Webb all right so

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it's not like one is better than the

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other they're designed to do different

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things Hubble is designed to look at

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Optical light visible light and web is

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designed to look at infrared light and

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there's a bit of an overlap okay and

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where there is an overlap web being the

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newer telescope actually has has better

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resolution and actually one of the main

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advantages of web is that it can get to

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a certain uh depth of of an image faster

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it has newer detectors it can get to it

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can get to the uh the faint stuff faster

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than Hubble could do on the same thing

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but really you know uh instead of

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choosing between a sports car and an SUV

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why not both huh and that's what we've

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got here we have a wonderful optical

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telescope we have a wonderful infrared

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telescope and we're sort of in like a

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golden age where we get to use them both

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together to learn more we take images

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with Hubble we take images with web We

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compare them we get new new views we

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have more understanding and more science

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so these next few years when we have

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both telescopes operational are going to

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be wonderful and I really look forward

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to the results we're going to get

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all right that's our news summary for

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today

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um let me stop my screen share

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um and invite spirillo to turn on his

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screen share unfortunately spur one of

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the reasons we started this late is that

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spirillo's uh camera is not working uh

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his screen share is working but not his

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camera so spirilla whenever you have a

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red bat there he started his screen

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share all right so ladies and gentlemen

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our speaker tonight a descendant of

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Dante elegieri esperel de solego

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allegieri and the most important thing

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about him to know is that he's not just

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some random descendant he's actually an

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astrophysicist he's retired but he did

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work at the astrophysical observatory in

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arcetri

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before he came in and did this research

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hello hello everybody thank you for

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inviting me

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for this

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conference

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we are going to make a big step back in

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time

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actually 700 years

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America was not yet discovered then

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uh anyway

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um

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yes I am a descendant of Dante

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uh but you know this is not the

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important thing

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because I have no merit in it and of

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um it's it's not an easy thing to live

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with

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but I was helped by my father

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um when I was very young starting to

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00:12:27,170 --> 00:12:24,600
reading six years old

277
00:12:28,370 --> 00:12:27,180
he gave me

278
00:12:30,009 --> 00:12:28,380
um

279
00:12:34,670 --> 00:12:30,019
a book sign

280
00:12:36,490 --> 00:12:34,680
which had some verses of Dante

281
00:12:40,310 --> 00:12:36,500
which are the

282
00:12:43,190 --> 00:12:40,320
few ones that I know by heart

283
00:12:44,949 --> 00:12:43,200
and they say

284
00:12:48,350 --> 00:12:44,959
um actually

285
00:12:52,190 --> 00:12:48,360
let me make a note

286
00:12:53,449 --> 00:12:52,200
I'm going to cite lots of verses of

287
00:12:56,569 --> 00:12:53,459
Dante

288
00:12:58,730 --> 00:12:56,579
I'm going to show them to you in Italian

289
00:12:59,569 --> 00:12:58,740
because this is the way down to vote

290
00:13:04,910 --> 00:12:59,579
them

291
00:13:06,470 --> 00:13:04,920
so this verses you can see it in Italian

292
00:13:10,670 --> 00:13:06,480
and they say

293
00:13:13,190 --> 00:13:10,680
oh little our blood nobility you are

294
00:13:14,389 --> 00:13:13,200
like a month or that soon will get

295
00:13:18,050 --> 00:13:14,399
shorter

296
00:13:19,190 --> 00:13:18,060
so that if you don't add to it day by

297
00:13:24,230 --> 00:13:19,200
day

298
00:13:26,930 --> 00:13:24,240
time will go around with scissors

299
00:13:28,990 --> 00:13:26,940
so this means that nobility and

300
00:13:34,129 --> 00:13:29,000
descendants

301
00:13:37,670 --> 00:13:34,139
have little meaning you if you don't add

302
00:13:42,590 --> 00:13:39,889
um okay so this is what we're trying to

303
00:13:43,310 --> 00:13:42,600
do trying to do tonight

304
00:13:44,870 --> 00:13:43,320
um

305
00:13:46,250 --> 00:13:44,880
and

306
00:13:48,530 --> 00:13:46,260
um

307
00:13:50,050 --> 00:13:48,540
in fact

308
00:13:54,129 --> 00:13:50,060
I've

309
00:13:56,569 --> 00:13:54,139
studied Dante in high school but very

310
00:13:58,310 --> 00:13:56,579
little after that

311
00:14:01,490 --> 00:13:58,320
until

312
00:14:05,509 --> 00:14:01,500
uh some years ago

313
00:14:07,490 --> 00:14:05,519
after most of my astrophysical career

314
00:14:11,810 --> 00:14:07,500
had gone

315
00:14:14,509 --> 00:14:11,820
that I am sharing with Dante something

316
00:14:17,949 --> 00:14:14,519
very important apart from my last name

317
00:14:20,690 --> 00:14:17,959
which is the the passion for astronomy

318
00:14:23,810 --> 00:14:20,700
Dante had this passion there is no doubt

319
00:14:24,829 --> 00:14:23,820
about it in in the con video which is

320
00:14:26,090 --> 00:14:24,839
the

321
00:14:28,129 --> 00:14:26,100
um

322
00:14:32,090 --> 00:14:28,139
if you want the

323
00:14:35,170 --> 00:14:32,100
um 3D philosophical historic or

324
00:14:38,750 --> 00:14:35,180
technical scientific 3D that Dante wrote

325
00:14:42,889 --> 00:14:38,760
in the beginning of the convivor he says

326
00:14:45,410 --> 00:14:42,899
that science is is our ultimate the

327
00:14:51,470 --> 00:14:45,420
ultimate Perfection of our soul

328
00:14:54,110 --> 00:14:51,480
in which states our ultimate happiness

329
00:14:59,150 --> 00:14:54,120
so this is clearly

330
00:15:01,810 --> 00:14:59,160
at the Declaration of love for science

331
00:15:05,389 --> 00:15:01,820
and a little later still in the convivio

332
00:15:08,509 --> 00:15:05,399
Dante says well this astronomy

333
00:15:11,150 --> 00:15:08,519
more than any of the other Sciences is

334
00:15:13,670 --> 00:15:11,160
noble and high because its subject is

335
00:15:16,370 --> 00:15:13,680
noble and high and deals about the

336
00:15:20,030 --> 00:15:16,380
movement of the sky Etc

337
00:15:23,689 --> 00:15:20,040
so science is perfection of our soul and

338
00:15:26,449 --> 00:15:23,699
ultimate happiness and among science is

339
00:15:30,110 --> 00:15:26,459
the the highest and most noble is

340
00:15:33,170 --> 00:15:30,120
astronomy there is obviously clear

341
00:15:36,410 --> 00:15:33,180
passion for astronomy in Dante and he

342
00:15:39,050 --> 00:15:36,420
shows it throughout his works and mostly

343
00:15:40,610 --> 00:15:39,060
of course in in The Divine Comedy in

344
00:15:42,590 --> 00:15:40,620
fact The Divine Comedy

345
00:15:46,550 --> 00:15:42,600
is the story

346
00:15:49,730 --> 00:15:46,560
in Poetic form of a journey throughout

347
00:15:51,710 --> 00:15:49,740
the whole universe like a science

348
00:15:53,150 --> 00:15:51,720
fiction book

349
00:15:54,410 --> 00:15:53,160
anyway

350
00:15:58,610 --> 00:15:54,420
um

351
00:16:01,970 --> 00:15:58,620
of course Dante was talking

352
00:16:11,290 --> 00:16:06,530
astronomy as it was known at its time

353
00:16:17,150 --> 00:16:13,189
leading

354
00:16:21,470 --> 00:16:17,160
astronomy the Ptolemy system done by the

355
00:16:24,230 --> 00:16:21,480
Greeks and got to

356
00:16:27,829 --> 00:16:24,240
to Dante to Europe

357
00:16:30,769 --> 00:16:27,839
back again through the Arabs because

358
00:16:34,569 --> 00:16:30,779
because after the the burn of the

359
00:16:41,030 --> 00:16:37,069
most of the knowledge in the western

360
00:16:43,730 --> 00:16:41,040
world was lost but fortunately the Arabs

361
00:16:46,269 --> 00:16:43,740
kept it and and then they trusted it

362
00:16:50,050 --> 00:16:46,279
back to Europe

363
00:16:55,790 --> 00:16:50,060
uh later okay anyway the ptolemyc system

364
00:16:58,730 --> 00:16:55,800
you know he it says that the Earth is in

365
00:17:01,790 --> 00:16:58,740
the middle of the word of the universe

366
00:17:05,090 --> 00:17:01,800
air is standing still in the middle of

367
00:17:07,130 --> 00:17:05,100
the universe and then there are objects

368
00:17:10,549 --> 00:17:07,140
turning around it

369
00:17:13,549 --> 00:17:10,559
first the moon Mercury the sun the sun

370
00:17:18,230 --> 00:17:13,559
is also turning around the Earth

371
00:17:21,829 --> 00:17:18,240
then Venus Mars Jupiter Saturn

372
00:17:24,289 --> 00:17:21,839
and then the fixed Stars so that's the

373
00:17:26,090 --> 00:17:24,299
the system

374
00:17:29,210 --> 00:17:26,100
done this time and of course he's

375
00:17:33,650 --> 00:17:30,770
um

376
00:17:36,770 --> 00:17:33,660
well there are several ways in which

377
00:17:40,549 --> 00:17:36,780
Dante uses astronomy in his works

378
00:17:44,409 --> 00:17:40,559
and one of them maybe well one of the

379
00:17:48,770 --> 00:17:44,419
most important ones is is that he uses

380
00:17:50,150 --> 00:17:48,780
astronomy to tell about time

381
00:17:55,450 --> 00:17:50,160
um

382
00:18:00,289 --> 00:17:55,460
timing of events is often uh shown

383
00:18:03,950 --> 00:18:00,299
with an astronomical uh reference for

384
00:18:05,690 --> 00:18:03,960
example here in in The Inferno

385
00:18:08,169 --> 00:18:05,700
he says

386
00:18:13,669 --> 00:18:08,179
that yesterday

387
00:18:17,390 --> 00:18:13,679
was full moon yesterday was the night in

388
00:18:20,330 --> 00:18:17,400
which Dante had hinted Inferno

389
00:18:22,930 --> 00:18:20,340
it started his trip and and so that it

390
00:18:25,310 --> 00:18:22,940
was full moon

391
00:18:30,350 --> 00:18:25,320
uh well

392
00:18:33,710 --> 00:18:30,360
this is not enough to tell about the the

393
00:18:35,870 --> 00:18:33,720
timing of Dante's Journey

394
00:18:38,090 --> 00:18:35,880
actually there's something important to

395
00:18:41,330 --> 00:18:38,100
tell about this uh of course dentist

396
00:18:44,690 --> 00:18:41,340
journey is an imaginary one

397
00:18:48,049 --> 00:18:44,700
but Dante was not a person who did

398
00:18:51,770 --> 00:18:48,059
things by chance no no no even his

399
00:18:54,730 --> 00:18:51,780
imaginary Journey had to have a place in

400
00:18:58,070 --> 00:18:54,740
time very precise place in time

401
00:19:01,370 --> 00:18:58,080
all readers of Dante throughout the

402
00:19:03,409 --> 00:19:01,380
centuries agree about this that the the

403
00:19:06,770 --> 00:19:03,419
journey had to have

404
00:19:09,470 --> 00:19:06,780
a precise timing

405
00:19:12,409 --> 00:19:09,480
um the problem is that

406
00:19:16,490 --> 00:19:12,419
the leaders of Dante do not agree about

407
00:19:22,549 --> 00:19:17,990
um

408
00:19:26,510 --> 00:19:22,559
of course and so let's look at this

409
00:19:28,490 --> 00:19:26,520
um he he says that it was full moon but

410
00:19:31,610 --> 00:19:28,500
you know full moon there is one every

411
00:19:35,090 --> 00:19:31,620
month and and of course 12 or 13 every

412
00:19:36,289 --> 00:19:35,100
year so it doesn't tell you much

413
00:19:39,350 --> 00:19:36,299
um

414
00:19:42,710 --> 00:19:39,360
most of the readers of Dante

415
00:19:47,150 --> 00:19:42,720
particularly in the old times thought

416
00:19:51,770 --> 00:19:47,160
that the Journey of Dante had happened

417
00:19:54,230 --> 00:19:51,780
in the spring of 1300.

418
00:19:57,710 --> 00:19:54,240
Well Spring is easy because Dante says

419
00:19:59,270 --> 00:19:57,720
that the the sun was in res so it was

420
00:20:03,590 --> 00:19:59,280
spring

421
00:20:05,990 --> 00:20:03,600
but 1300 why 1300 because 1300 was the

422
00:20:09,370 --> 00:20:06,000
first Jubilee year

423
00:20:14,150 --> 00:20:09,380
that that poop

424
00:20:17,510 --> 00:20:14,160
Bonifacio the eight had uh

425
00:20:22,669 --> 00:20:19,010
um

426
00:20:23,330 --> 00:20:22,679
and there are also other historical

427
00:20:25,909 --> 00:20:23,340
um

428
00:20:28,490 --> 00:20:25,919
mentions in The Divine Comedy that

429
00:20:32,289 --> 00:20:28,500
referred to thirteen hundred

430
00:20:34,730 --> 00:20:32,299
the problem is that the astronomical

431
00:20:36,529 --> 00:20:34,740
reference is in Divine Comedy do not

432
00:20:38,230 --> 00:20:36,539
agree with this

433
00:20:41,450 --> 00:20:38,240
in particular

434
00:20:44,450 --> 00:20:41,460
this this event

435
00:20:46,029 --> 00:20:44,460
you know we are at the start of the

436
00:20:51,110 --> 00:20:46,039
Purgatory

437
00:20:53,750 --> 00:20:51,120
Dante it just come out of hell of the

438
00:20:57,650 --> 00:20:53,760
Earth or inside the Earth

439
00:21:00,650 --> 00:20:57,660
to back to see the stars as he says and

440
00:21:01,789 --> 00:21:00,660
of course the the first thing he does he

441
00:21:05,270 --> 00:21:01,799
looks up

442
00:21:07,250 --> 00:21:05,280
and he sees what does he see of course

443
00:21:10,190 --> 00:21:07,260
he sees Venus because Venus is the

444
00:21:11,350 --> 00:21:10,200
brightest objects in the night sky apart

445
00:21:14,870 --> 00:21:11,360
from the Moon

446
00:21:17,690 --> 00:21:14,880
uh and of course if it's there you you

447
00:21:18,950 --> 00:21:17,700
would immediately see it and what does

448
00:21:21,650 --> 00:21:18,960
he say

449
00:21:24,529 --> 00:21:21,660
you can read it in Italian it says that

450
00:21:28,430 --> 00:21:24,539
the the planet Venus

451
00:21:32,390 --> 00:21:28,440
uh was in in the east

452
00:21:34,909 --> 00:21:32,400
and it was in the constellation of of

453
00:21:39,049 --> 00:21:34,919
pieces

454
00:21:42,289 --> 00:21:39,059
well this is very clear very clear

455
00:21:45,110 --> 00:21:42,299
you know Venus

456
00:21:50,289 --> 00:21:45,120
can be seen either

457
00:21:57,409 --> 00:21:54,770
or in the morning before sunrise

458
00:22:00,049 --> 00:21:57,419
this is because the the orbit of Venus

459
00:22:02,870 --> 00:22:00,059
is inside the orbit of the earth and so

460
00:22:05,570 --> 00:22:02,880
you can only see Venus quite close to

461
00:22:12,350 --> 00:22:09,529
now the problem and you know the whether

462
00:22:15,230 --> 00:22:12,360
you see Venus in the evening or in the

463
00:22:18,350 --> 00:22:15,240
morning depends on the relative position

464
00:22:21,890 --> 00:22:18,360
of of Venus the Earth and the sun which

465
00:22:23,690 --> 00:22:21,900
changes but changes it takes many months

466
00:22:27,049 --> 00:22:23,700
to change

467
00:22:30,890 --> 00:22:27,059
and the problem is that in the in the

468
00:22:34,510 --> 00:22:30,900
spring of 1300

469
00:22:37,730 --> 00:22:34,520
Venus was

470
00:22:39,770 --> 00:22:37,740
seen in in the evening not in the

471
00:22:41,810 --> 00:22:39,780
morning and he was not in the business

472
00:22:44,450 --> 00:22:41,820
was in in Taurus

473
00:22:48,230 --> 00:22:44,460
so it doesn't correspond to Dan what

474
00:22:49,789 --> 00:22:48,240
Dante says the spring of 1300

475
00:22:52,490 --> 00:22:49,799
is not a good

476
00:22:55,970 --> 00:22:52,500
date for Dante's Journey according to

477
00:22:58,490 --> 00:22:55,980
this astronomical uh reference

478
00:23:03,529 --> 00:22:58,500
on the other hand

479
00:23:07,070 --> 00:23:05,149
uh

480
00:23:10,010 --> 00:23:07,080
in the spring

481
00:23:12,350 --> 00:23:10,020
Venus was seen in the morning and it was

482
00:23:15,649 --> 00:23:12,360
in the constellation of species just

483
00:23:19,130 --> 00:23:15,659
like that it says so for us astronomers

484
00:23:22,430 --> 00:23:19,140
the Journey of Dante

485
00:23:26,649 --> 00:23:22,440
started in the night between the 24th

486
00:23:28,370 --> 00:23:26,659
and the 25th of March

487
00:23:31,130 --> 00:23:28,380
1301.

488
00:23:33,649 --> 00:23:31,140
it was full moon

489
00:23:35,990 --> 00:23:33,659
Venus was seen in the morning and it was

490
00:23:37,909 --> 00:23:36,000
in the pieces

491
00:23:42,470 --> 00:23:37,919
now you can ask

492
00:23:47,810 --> 00:23:44,810
well

493
00:23:56,750 --> 00:23:53,810
was promoted by Pope Bonifacio the eight

494
00:23:58,549 --> 00:23:56,760
and this book was not someone that Dante

495
00:24:00,529 --> 00:23:58,559
liked

496
00:24:02,870 --> 00:24:00,539
but anyway

497
00:24:06,190 --> 00:24:02,880
uh

498
00:24:09,409 --> 00:24:06,200
Dante was from Florence and at the time

499
00:24:11,029 --> 00:24:09,419
the calendar in Florence was such that

500
00:24:15,830 --> 00:24:11,039
the first

501
00:24:19,490 --> 00:24:15,840
day of the year was the 25th of March

502
00:24:23,029 --> 00:24:19,500
so the night between the 24th and the

503
00:24:26,210 --> 00:24:23,039
25th of March was still in the Jubilee

504
00:24:31,070 --> 00:24:26,220
year if you really want to listen to

505
00:24:33,529 --> 00:24:31,080
that anyway I don't want to

506
00:24:36,649 --> 00:24:33,539
uh

507
00:24:41,450 --> 00:24:36,659
um hide the fact that in the Divine

508
00:24:43,789 --> 00:24:41,460
Comedy there is a conflict between uh

509
00:24:44,930 --> 00:24:43,799
historical dating and an astronomical

510
00:24:47,510 --> 00:24:44,940
dating

511
00:24:50,090 --> 00:24:47,520
nobody has solved this problem and of

512
00:24:52,669 --> 00:24:50,100
course it's we cannot solve it now

513
00:24:54,710 --> 00:24:52,679
I just want to point it out and of

514
00:24:57,890 --> 00:24:54,720
course for us astronomers the the right

515
00:25:00,710 --> 00:24:57,900
dating is the economical one

516
00:25:02,930 --> 00:25:00,720
uh yeah let's go on

517
00:25:04,909 --> 00:25:02,940
without astronomical reference we are

518
00:25:06,289 --> 00:25:04,919
still on the first

519
00:25:09,890 --> 00:25:06,299
um

520
00:25:12,250 --> 00:25:09,900
uh Kanto of the Purgatory

521
00:25:17,630 --> 00:25:12,260
so just after

522
00:25:19,310 --> 00:25:17,640
Dante looked up and saw Venus

523
00:25:20,750 --> 00:25:19,320
he says

524
00:25:23,330 --> 00:25:20,760
I looked

525
00:25:24,649 --> 00:25:23,340
on my right

526
00:25:27,950 --> 00:25:24,659
and

527
00:25:31,610 --> 00:25:27,960
looked for the other Pole

528
00:25:32,510 --> 00:25:31,620
and I saw four stars which were we had

529
00:25:36,769 --> 00:25:32,520
no

530
00:25:39,649 --> 00:25:36,779
had never seen before except

531
00:25:41,930 --> 00:25:39,659
to the first people except from the

532
00:25:43,070 --> 00:25:41,940
first people

533
00:25:47,990 --> 00:25:43,080
well

534
00:25:50,890 --> 00:25:49,269
you know

535
00:25:53,750 --> 00:25:50,900
Dante

536
00:25:57,350 --> 00:25:53,760
was someone who would

537
00:26:00,110 --> 00:25:57,360
travel by Night several times and at

538
00:26:02,690 --> 00:26:00,120
those times of course he didn't have any

539
00:26:07,390 --> 00:26:02,700
lights there were no lights so the only

540
00:26:10,190 --> 00:26:07,400
things he could use to orient himself

541
00:26:13,850 --> 00:26:10,200
knowing where he was going

542
00:26:15,769 --> 00:26:13,860
was look at the stars and you know in in

543
00:26:17,990 --> 00:26:15,779
the northern hemisphere if you want to

544
00:26:21,710 --> 00:26:18,000
orient yourself the first thing you do

545
00:26:23,169 --> 00:26:21,720
you look at the uh at the northern Stars

546
00:26:47,930 --> 00:26:23,179
the

547
00:26:49,450 --> 00:26:47,940
so

548
00:26:54,409 --> 00:26:49,460
now

549
00:26:57,710 --> 00:26:54,419
Dante has got out of the of the Earth on

550
00:27:00,950 --> 00:26:57,720
the other side he knew that

551
00:27:04,610 --> 00:27:00,960
so he knew that he could not look at the

552
00:27:05,810 --> 00:27:04,620
Polar Star the northern polar Stars

553
00:27:09,529 --> 00:27:05,820
but

554
00:27:12,110 --> 00:27:09,539
still he knew that the

555
00:27:15,710 --> 00:27:12,120
the rotation axis of the Earth

556
00:27:19,549 --> 00:27:15,720
would would get to the to the sky also

557
00:27:24,310 --> 00:27:19,559
to the South so he in order to to

558
00:27:28,610 --> 00:27:24,320
understand how he was I would Escape how

559
00:27:30,169 --> 00:27:28,620
he was oriented he he looks at the other

560
00:27:32,990 --> 00:27:30,179
Pole

561
00:27:35,690 --> 00:27:33,000
that's what he does and

562
00:27:41,390 --> 00:27:39,289
the the problem is that on the other on

563
00:27:43,610 --> 00:27:41,400
the southern sky

564
00:27:45,950 --> 00:27:43,620
where the rotation axis of the earth

565
00:27:48,830 --> 00:27:45,960
gets to the gets to the sky there is no

566
00:27:50,330 --> 00:27:48,840
blight star they are not lucky

567
00:27:54,230 --> 00:27:50,340
as we are

568
00:27:57,710 --> 00:27:54,240
but near there there is a Southern Cross

569
00:28:01,070 --> 00:27:57,720
the sound of cross is the four stars so

570
00:28:05,049 --> 00:28:01,080
he saw he sees the four stars

571
00:28:07,669 --> 00:28:05,059
now the one one could ask

572
00:28:10,430 --> 00:28:07,679
how did he know about the Southern Cross

573
00:28:15,890 --> 00:28:10,440
well that's easy that's easy because

574
00:28:17,750 --> 00:28:15,900
Dante had uh access to uh star Maps done

575
00:28:19,490 --> 00:28:17,760
by the herbs

576
00:28:21,169 --> 00:28:19,500
and the Arabs

577
00:28:23,210 --> 00:28:21,179
because they knew about the Southern

578
00:28:25,190 --> 00:28:23,220
Cross because you can see you can see

579
00:28:27,470 --> 00:28:25,200
the Southern Cross from Saudi Arabia of

580
00:28:29,570 --> 00:28:27,480
all three hours were traveling around so

581
00:28:32,330 --> 00:28:29,580
they knew about the the Southern Cross

582
00:28:34,310 --> 00:28:32,340
and they had put it in the in the in the

583
00:28:37,130 --> 00:28:34,320
star maps that Dante could could have

584
00:28:39,850 --> 00:28:37,140
access to so there is no problem that he

585
00:28:43,250 --> 00:28:39,860
knew about the the the

586
00:28:45,649 --> 00:28:43,260
sound for us but the problem is is the

587
00:28:49,070 --> 00:28:45,659
following verse which says that these

588
00:28:52,250 --> 00:28:49,080
four stars had never been seen

589
00:28:54,529 --> 00:28:52,260
uh before except to the

590
00:28:59,570 --> 00:28:54,539
first people

591
00:29:01,850 --> 00:28:59,580
the Southern Cross

592
00:29:05,390 --> 00:29:01,860
now again here there is an easy answer

593
00:29:06,769 --> 00:29:05,400
and a more clever one the easy answer is

594
00:29:10,430 --> 00:29:06,779
well

595
00:29:14,269 --> 00:29:10,440
the first people are Adam and Eve Adam

596
00:29:16,789 --> 00:29:14,279
and Eve lived in the in the terrestrial

597
00:29:18,590 --> 00:29:16,799
Paradise such as the paradise is on the

598
00:29:20,710 --> 00:29:18,600
top of the mountain of purgatory and of

599
00:29:24,970 --> 00:29:20,720
course it is on the other side so they

600
00:29:27,889 --> 00:29:24,980
they they would have seen the sound

601
00:29:31,850 --> 00:29:27,899
Southern Cross

602
00:29:33,190 --> 00:29:31,860
but but that's uh not a nice explanation

603
00:29:35,810 --> 00:29:33,200
and

604
00:29:39,169 --> 00:29:35,820
it gets

605
00:29:41,029 --> 00:29:39,179
it's not right also because Dante would

606
00:29:44,930 --> 00:29:41,039
have never

607
00:29:47,750 --> 00:29:44,940
called people two persons Adam and Eve

608
00:29:50,870 --> 00:29:47,760
are not people they are two

609
00:29:54,350 --> 00:29:50,880
so if he says about people it cannot be

610
00:29:56,810 --> 00:29:54,360
Adam and Eve and there is a much more uh

611
00:29:58,970 --> 00:29:56,820
interesting explanation to this which

612
00:30:01,210 --> 00:29:58,980
has to do with the perceptional

613
00:30:03,649 --> 00:30:01,220
procession of equinoxes

614
00:30:06,169 --> 00:30:03,659
uh now I suppose I don't need to explain

615
00:30:09,470 --> 00:30:06,179
to you what the perception of equinoxes

616
00:30:11,830 --> 00:30:09,480
is well it's a simple fact that the

617
00:30:15,649 --> 00:30:11,840
rotation axis of the Earth

618
00:30:17,450 --> 00:30:15,659
turns around in a cycle which is about

619
00:30:19,789 --> 00:30:17,460
26 uh

620
00:30:22,130 --> 00:30:19,799
thousand years long

621
00:30:22,930 --> 00:30:22,140
which makes that the

622
00:30:26,450 --> 00:30:22,940
um

623
00:30:30,049 --> 00:30:26,460
the rotation axis of the earth points to

624
00:30:32,810 --> 00:30:30,059
different Stars throughout the centuries

625
00:30:34,909 --> 00:30:32,820
and of course also that the the stars

626
00:30:38,690 --> 00:30:34,919
that you can see at any latitude would

627
00:30:42,230 --> 00:30:38,700
change in in the centuries and in fact

628
00:30:44,930 --> 00:30:42,240
if you use stellarium

629
00:30:50,870 --> 00:30:44,940
to

630
00:30:52,610 --> 00:30:50,880
seven thousand years ago

631
00:30:54,289 --> 00:30:52,620
well you can clearly see that the

632
00:30:55,909 --> 00:30:54,299
Southern Cross was vegetable from

633
00:30:58,909 --> 00:30:55,919
Florence because

634
00:31:01,310 --> 00:30:58,919
of the possession of the equinoxes why

635
00:31:05,269 --> 00:31:01,320
why did I put did I

636
00:31:07,730 --> 00:31:05,279
try 7000 years ago well because

637
00:31:11,049 --> 00:31:07,740
at the time of Dante he was told that

638
00:31:13,610 --> 00:31:11,059
the the creation of the world and and

639
00:31:17,810 --> 00:31:13,620
soon after that the

640
00:31:22,010 --> 00:31:17,820
um population of

641
00:31:24,769 --> 00:31:22,020
the Earth by the descendants of Adam and

642
00:31:27,889 --> 00:31:24,779
Eve happened five thousand years before

643
00:31:30,049 --> 00:31:27,899
Christ which is seven thousand years ago

644
00:31:32,149 --> 00:31:30,059
so seven thousand years ago

645
00:31:34,549 --> 00:31:32,159
the sounding Clause was visible at our

646
00:31:37,370 --> 00:31:34,559
latitudes and the first people that

647
00:31:39,409 --> 00:31:37,380
Dante talks about are actually the the

648
00:31:41,750 --> 00:31:39,419
descendants of Adam and Eve who

649
00:31:45,769 --> 00:31:41,760
populated the

650
00:31:47,810 --> 00:31:45,779
um our lands the Euro and our latitudes

651
00:31:49,070 --> 00:31:47,820
which is a much more satisfactory

652
00:31:50,870 --> 00:31:49,080
explanation

653
00:31:52,350 --> 00:31:50,880
okay

654
00:31:54,110 --> 00:31:52,360
um

655
00:31:56,269 --> 00:31:54,120
[Music]

656
00:31:59,810 --> 00:31:56,279
okay well

657
00:32:02,029 --> 00:31:59,820
the question is did Dante know about the

658
00:32:02,750 --> 00:32:02,039
procession of the equinoxes of course he

659
00:32:04,789 --> 00:32:02,760
did

660
00:32:07,490 --> 00:32:04,799
in fact in the convenient again he says

661
00:32:11,750 --> 00:32:07,500
that there is this movement very slow

662
00:32:15,769 --> 00:32:11,760
movement which goes from west to east

663
00:32:18,769 --> 00:32:15,779
by a degree every hundred years

664
00:32:22,370 --> 00:32:18,779
a degree every 100 years means that to

665
00:32:27,169 --> 00:32:22,380
do a full term 360 degrees

666
00:32:28,850 --> 00:32:27,179
it would take 36 000 years no 36 000

667
00:32:32,210 --> 00:32:28,860
years is

668
00:32:33,769 --> 00:32:32,220
is a bit longer than the 26 000 years

669
00:32:35,510 --> 00:32:33,779
that we know is the period of the

670
00:32:39,350 --> 00:32:35,520
possession of the equinoxes but that

671
00:32:40,850 --> 00:32:39,360
doesn't matter uh okay the possession of

672
00:32:43,850 --> 00:32:40,860
the Equinox is the period was

673
00:32:46,250 --> 00:32:43,860
overestimated by some

674
00:32:48,649 --> 00:32:46,260
amount but that's not the problem he

675
00:32:51,049 --> 00:32:48,659
knew about it and he could he could tell

676
00:32:53,930 --> 00:32:51,059
that that the sounding Clause could be

677
00:32:55,669 --> 00:32:53,940
visible by Florence long ago

678
00:32:57,430 --> 00:32:55,679
okay

679
00:32:59,930 --> 00:32:57,440
um

680
00:33:01,370 --> 00:32:59,940
now we go to

681
00:33:02,529 --> 00:33:01,380
um

682
00:33:06,830 --> 00:33:02,539
another

683
00:33:11,870 --> 00:33:06,840
part of the Divine Comedy it's the uh 27

684
00:33:14,570 --> 00:33:11,880
26th Kanto of The Inferno and there is

685
00:33:17,149 --> 00:33:14,580
Ulysses who well actually Dante and

686
00:33:20,090 --> 00:33:17,159
virgilio encounter

687
00:33:23,330 --> 00:33:20,100
ulises and Ulysses tell

688
00:33:30,950 --> 00:33:27,130
his last trip recently the last trip

689
00:33:34,070 --> 00:33:30,960
when he was already old

690
00:33:34,970 --> 00:33:34,080
with his uh

691
00:33:39,710 --> 00:33:34,980
um

692
00:33:44,230 --> 00:33:39,720
uh friends were also old and they what

693
00:33:49,250 --> 00:33:44,240
they did they went to Gibraltar

694
00:33:53,870 --> 00:33:49,260
Gibraltar was the was told at the time

695
00:33:57,950 --> 00:33:53,880
of Dante to be the extreme

696
00:34:00,350 --> 00:33:57,960
um west of the of the world and it was

697
00:34:03,950 --> 00:34:00,360
something that you could not

698
00:34:05,870 --> 00:34:03,960
go further because there was the rest

699
00:34:09,470 --> 00:34:05,880
was completely unknown

700
00:34:14,510 --> 00:34:09,480
but in fact ulises he wanted to discover

701
00:34:16,250 --> 00:34:14,520
what was after that so what he did uh

702
00:34:20,409 --> 00:34:16,260
you see

703
00:34:24,290 --> 00:34:20,419
um he crossed Gibraltar and of course

704
00:34:29,690 --> 00:34:24,300
when well doing that he would leave

705
00:34:33,349 --> 00:34:29,700
Sevilla so Spain to his right and to his

706
00:34:34,909 --> 00:34:33,359
left he would leave shelter which is in

707
00:34:38,210 --> 00:34:34,919
maroc

708
00:34:41,750 --> 00:34:38,220
and and okay well this shows actually

709
00:34:45,829 --> 00:34:41,760
what is the geography at Dante's time

710
00:34:49,490 --> 00:34:45,839
you see these are the emerged lands that

711
00:34:52,310 --> 00:34:49,500
were to to exist at that this time they

712
00:34:55,550 --> 00:34:52,320
are all in the Northern Hemisphere and

713
00:34:56,750 --> 00:34:55,560
not by chance Jerusalem is at the center

714
00:35:00,230 --> 00:34:56,760
of them

715
00:35:03,230 --> 00:35:00,240
if you go 90 degrees to the west of

716
00:35:06,530 --> 00:35:03,240
Jerusalem you get to to Gibraltar

717
00:35:08,329 --> 00:35:06,540
if you go 90 degrees to the east you get

718
00:35:10,730 --> 00:35:08,339
to the

719
00:35:13,010 --> 00:35:10,740
um the exit of ganja the ganja river

720
00:35:15,710 --> 00:35:13,020
which was thought to be the extreme East

721
00:35:18,609 --> 00:35:15,720
and then to the north to the northern

722
00:35:21,650 --> 00:35:18,619
Europe and and to the South to

723
00:35:23,450 --> 00:35:21,660
equatorial Africa so that were the

724
00:35:28,970 --> 00:35:23,460
emergent lands

725
00:35:31,010 --> 00:35:28,980
uh so ulises uh crosses Gibraltar and of

726
00:35:34,730 --> 00:35:31,020
course what they did was of course they

727
00:35:36,349 --> 00:35:34,740
had the the back of their sheep in in

728
00:35:40,730 --> 00:35:36,359
the east

729
00:35:43,970 --> 00:35:40,740
and so they were going west but they

730
00:35:45,970 --> 00:35:43,980
would they would go left from the west

731
00:35:49,609 --> 00:35:45,980
or south

732
00:35:51,730 --> 00:35:49,619
and then of course going south

733
00:35:55,069 --> 00:35:51,740
at some point they crossed the equator

734
00:35:58,910 --> 00:35:55,079
and if I they say that that they would

735
00:36:03,109 --> 00:35:58,920
see all the stars from from from the

736
00:36:06,109 --> 00:36:03,119
Southern Hemisphere and and our pole was

737
00:36:08,510 --> 00:36:06,119
so low that it went below the Horizon

738
00:36:12,109 --> 00:36:08,520
you know when you cross the Equator the

739
00:36:15,109 --> 00:36:12,119
Northern Star doesn't get

740
00:36:15,890 --> 00:36:15,119
out of the sea

741
00:36:18,170 --> 00:36:15,900
um

742
00:36:22,370 --> 00:36:18,180
so they were going south this is another

743
00:36:25,310 --> 00:36:22,380
way to to see so they crossed Gibraltar

744
00:36:27,849 --> 00:36:25,320
they're going south crossing the Equator

745
00:36:30,770 --> 00:36:27,859
and they were going on and at some point

746
00:36:33,550 --> 00:36:30,780
they reached

747
00:36:37,910 --> 00:36:33,560
this mountain of purgatory which is a

748
00:36:42,349 --> 00:36:37,920
the opposite of Jerusalem you see

749
00:36:46,370 --> 00:36:42,359
and of course seeing this land after

750
00:36:50,630 --> 00:36:46,380
five months of traveling

751
00:36:53,150 --> 00:36:50,640
in in C because they they were happy but

752
00:36:57,370 --> 00:36:53,160
soon uh they were not happy anymore

753
00:37:05,690 --> 00:37:01,010
it started the storm which got to his

754
00:37:08,930 --> 00:37:05,700
boat and and uh make make the boat Turn

755
00:37:13,609 --> 00:37:08,940
three times and then four times the boat

756
00:37:16,609 --> 00:37:13,619
went down and and they and it sinked and

757
00:37:19,849 --> 00:37:17,630
um

758
00:37:23,150 --> 00:37:19,859
well

759
00:37:25,310 --> 00:37:23,160
so what I want to point to you is it's

760
00:37:27,050 --> 00:37:25,320
just actually one important thing which

761
00:37:28,550 --> 00:37:27,060
is actually the most important thing

762
00:37:32,569 --> 00:37:28,560
which I'm going to tell you which I

763
00:37:36,230 --> 00:37:34,010
um

764
00:37:38,329 --> 00:37:36,240
Dante

765
00:37:44,210 --> 00:37:38,339
as a

766
00:37:46,670 --> 00:37:44,220
how he was

767
00:37:51,410 --> 00:37:46,680
he could get

768
00:37:56,990 --> 00:37:51,420
contain into his mind all the knowledge

769
00:38:03,589 --> 00:38:00,829
this is something that for us it is hard

770
00:38:06,290 --> 00:38:03,599
to understand because we've lost this

771
00:38:08,270 --> 00:38:06,300
capability we've lost its capability not

772
00:38:11,510 --> 00:38:08,280
only because we're not genius as Dante

773
00:38:15,109 --> 00:38:11,520
was but also because the knowledge

774
00:38:15,890 --> 00:38:15,119
in all fields has

775
00:38:17,810 --> 00:38:15,900
um

776
00:38:21,230 --> 00:38:17,820
of course grown

777
00:38:24,530 --> 00:38:21,240
very much in all these centuries so that

778
00:38:25,370 --> 00:38:24,540
one single mind cannot contain all of

779
00:38:28,910 --> 00:38:25,380
them

780
00:38:29,450 --> 00:38:28,920
but Dante could do it

781
00:38:31,849 --> 00:38:29,460
um

782
00:38:34,730 --> 00:38:31,859
for us it's not easy to understand but

783
00:38:38,089 --> 00:38:34,740
there are several effects of from from

784
00:38:42,230 --> 00:38:38,099
this Fact one important one is that

785
00:38:46,609 --> 00:38:42,240
in order to understand Dante

786
00:38:48,890 --> 00:38:46,619
uh one person is not enough

787
00:38:52,970 --> 00:38:48,900
because we

788
00:38:58,010 --> 00:38:52,980
uh at our time we

789
00:39:00,730 --> 00:38:58,020
people who deal with knowledge

790
00:39:03,650 --> 00:39:00,740
if we want to

791
00:39:06,770 --> 00:39:03,660
say something new in the field of

792
00:39:09,770 --> 00:39:06,780
knowledge we have to specialize there is

793
00:39:11,329 --> 00:39:09,780
no way out of this

794
00:39:14,569 --> 00:39:11,339
so

795
00:39:16,310 --> 00:39:14,579
we are all specialized we know well one

796
00:39:22,250 --> 00:39:16,320
thing

797
00:39:25,430 --> 00:39:22,260
well we cannot know well

798
00:39:28,670 --> 00:39:25,440
so in order to explain that

799
00:39:31,609 --> 00:39:28,680
you you cannot listen to just one person

800
00:39:34,790 --> 00:39:31,619
you have to listen to several persons

801
00:39:36,290 --> 00:39:34,800
don't trust somebody who tells you I

802
00:39:38,810 --> 00:39:36,300
know everything about Dante that's not

803
00:39:41,450 --> 00:39:39,950
um

804
00:39:44,210 --> 00:39:41,460
so

805
00:39:47,750 --> 00:39:44,220
the other fact is that I'm going to talk

806
00:39:51,589 --> 00:39:47,760
to you about astronomy in Dante

807
00:39:55,490 --> 00:39:51,599
I'm and I don't want to uh say that this

808
00:39:58,810 --> 00:39:55,500
is all actually I invite you to listen

809
00:40:01,990 --> 00:39:58,820
to other people for the other aspects of

810
00:40:02,390 --> 00:40:02,000
uh of Dante

811
00:40:03,829 --> 00:40:02,400
[Music]

812
00:40:08,470 --> 00:40:03,839
um

813
00:40:14,270 --> 00:40:08,480
anyway so now I've talked to you about

814
00:40:16,609 --> 00:40:14,280
the the releases uh story in Dante just

815
00:40:19,250 --> 00:40:16,619
to show you about the geography but of

816
00:40:21,109 --> 00:40:19,260
course in in in in

817
00:40:23,150 --> 00:40:21,119
Ulysses stories in Dante there is much

818
00:40:28,190 --> 00:40:23,160
more but you have to listen to other

819
00:40:32,690 --> 00:40:30,710
um yeah the passage at the center of the

820
00:40:36,530 --> 00:40:32,700
Earth

821
00:40:40,490 --> 00:40:36,540
um you know Dante and Vegeta get down

822
00:40:42,589 --> 00:40:40,500
into hell until they reach the center of

823
00:40:45,349 --> 00:40:42,599
the earth at the center of the earth

824
00:40:48,770 --> 00:40:45,359
there is Lucifer

825
00:40:50,329 --> 00:40:48,780
um the devil who who is stuck there just

826
00:40:52,010 --> 00:40:50,339
at the center

827
00:40:56,870 --> 00:40:52,020
and

828
00:40:58,609 --> 00:40:56,880
so they go down Lucifer's body

829
00:41:01,490 --> 00:40:58,619
until

830
00:41:04,370 --> 00:41:01,500
uh they reached the center of the earth

831
00:41:06,290 --> 00:41:04,380
and at the time of Dante it was still

832
00:41:08,390 --> 00:41:06,300
that gravity

833
00:41:09,890 --> 00:41:08,400
was a property

834
00:41:12,349 --> 00:41:09,900
uh

835
00:41:14,410 --> 00:41:12,359
over the center of the Earth

836
00:41:16,310 --> 00:41:14,420
every

837
00:41:17,870 --> 00:41:16,320
body

838
00:41:21,349 --> 00:41:17,880
is

839
00:41:23,210 --> 00:41:21,359
attracted by the center of the Earth

840
00:41:25,130 --> 00:41:23,220
so what happens at the center of the

841
00:41:27,050 --> 00:41:25,140
earth is the gravity

842
00:41:28,609 --> 00:41:27,060
turns over

843
00:41:30,890 --> 00:41:28,619
so

844
00:41:34,690 --> 00:41:30,900
where when they go

845
00:41:37,069 --> 00:41:34,700
along the body of Lucifer at some point

846
00:41:42,589 --> 00:41:37,079
gravity turns over

847
00:41:46,190 --> 00:41:42,599
and and so what what they do is is they

848
00:41:48,230 --> 00:41:46,200
they were they were going down and at

849
00:41:51,109 --> 00:41:48,240
some point they're starting go up

850
00:41:53,030 --> 00:41:51,119
so that dances and in the beginning he

851
00:41:55,670 --> 00:41:53,040
thinks well are we going back into hell

852
00:41:57,770 --> 00:41:55,680
no they're not they're going to the

853
00:41:59,930 --> 00:41:57,780
other side of course we all know that

854
00:42:03,770 --> 00:41:59,940
this is not true and I don't need to

855
00:42:08,930 --> 00:42:05,450
um

856
00:42:12,790 --> 00:42:08,940
okay well this we have already said well

857
00:42:16,310 --> 00:42:12,800
that's that's another another

858
00:42:18,650 --> 00:42:16,320
uh aspect I want to tell you about

859
00:42:19,609 --> 00:42:18,660
astronomy in Dante you know the Milky

860
00:42:21,349 --> 00:42:19,619
Way

861
00:42:24,050 --> 00:42:21,359
Dante talks

862
00:42:28,069 --> 00:42:24,060
several times about the Milky Way in the

863
00:42:31,849 --> 00:42:28,079
hell and in the hell it refers to the

864
00:42:34,790 --> 00:42:31,859
the Greek mythological story about the

865
00:42:38,450 --> 00:42:34,800
origin of the Milky Way and and the

866
00:42:44,089 --> 00:42:38,460
Greek mythological story is that fetonte

867
00:42:46,010 --> 00:42:44,099
it was a son of Apollo the the god of of

868
00:42:49,250 --> 00:42:46,020
the Sun

869
00:42:56,329 --> 00:42:53,390
taken the Chariot of his father the

870
00:43:00,230 --> 00:42:56,339
childhood was taking the sun around and

871
00:43:04,309 --> 00:43:00,240
see he took he took this Chariot uh you

872
00:43:07,730 --> 00:43:04,319
know as a as a son uh stealing the cow

873
00:43:11,210 --> 00:43:07,740
with his father and since he was did not

874
00:43:12,730 --> 00:43:11,220
know how to drive how to drive it he

875
00:43:17,990 --> 00:43:12,740
went around

876
00:43:25,370 --> 00:43:18,000
the sky in a funny way and and and and

877
00:43:27,950 --> 00:43:25,380
and and that trip left this blinds

878
00:43:30,050 --> 00:43:27,960
steep across the sky which is the Milky

879
00:43:31,970 --> 00:43:30,060
Way so that's the that's the

880
00:43:35,690 --> 00:43:31,980
mythological story and then we first

881
00:43:37,730 --> 00:43:35,700
read in the hair actually not just one

882
00:43:39,170 --> 00:43:37,740
time a couple of times

883
00:43:42,530 --> 00:43:39,180
but then

884
00:43:45,349 --> 00:43:42,540
uh in the in the paradise

885
00:43:48,890 --> 00:43:45,359
easy he talks again about the Milky Way

886
00:43:50,930 --> 00:43:48,900
and and he says you see here that the

887
00:43:56,329 --> 00:43:50,940
Milky Way is

888
00:43:58,130 --> 00:43:56,339
is made of minor and major lines which

889
00:44:01,910 --> 00:43:58,140
is Stars

890
00:44:05,390 --> 00:44:01,920
so this is our our view and actually in

891
00:44:07,490 --> 00:44:05,400
the con video he is much more precise

892
00:44:10,430 --> 00:44:07,500
about this

893
00:44:13,670 --> 00:44:10,440
um and he says that the Galaxy is

894
00:44:18,050 --> 00:44:13,680
nothing nothing else than a a multitude

895
00:44:21,349 --> 00:44:18,060
of of fixed stars that in that part are

896
00:44:23,089 --> 00:44:21,359
so small that we cannot distinguish them

897
00:44:30,530 --> 00:44:23,099
but

898
00:44:33,470 --> 00:44:30,540
that we call Galaxy so this is very

899
00:44:36,050 --> 00:44:33,480
clear so Dante knew that the Galaxy was

900
00:44:38,690 --> 00:44:36,060
made of stars but he was

901
00:44:43,370 --> 00:44:38,700
as a medieval man he was in the middle

902
00:44:48,410 --> 00:44:43,380
between the old mythological stories and

903
00:44:48,420 --> 00:44:52,370
um oops

904
00:44:56,750 --> 00:44:55,490
well this is an image of of the Milky

905
00:44:58,430 --> 00:44:56,760
Way

906
00:45:01,190 --> 00:44:58,440
um as we know it

907
00:45:05,750 --> 00:45:01,200
I don't need to tell you about the Milky

908
00:45:10,069 --> 00:45:05,760
Way uh this is an external Galaxy which

909
00:45:12,710 --> 00:45:10,079
uh uh looks very similar to what the

910
00:45:16,069 --> 00:45:12,720
Milky Way would look like if we could be

911
00:45:18,050 --> 00:45:17,270
okay

912
00:45:21,650 --> 00:45:18,060
um

913
00:45:25,730 --> 00:45:21,660
this is the one but last uh theme that I

914
00:45:31,670 --> 00:45:28,630
um it

915
00:45:34,490 --> 00:45:31,680
we are dealing about errors we're

916
00:45:37,990 --> 00:45:34,500
dealing about mistakes

917
00:45:41,150 --> 00:45:38,000
now of course you know very well that

918
00:45:43,130 --> 00:45:41,160
mistakes are not a problem for us

919
00:45:45,829 --> 00:45:43,140
scientists

920
00:45:48,589 --> 00:45:45,839
actually we know that

921
00:45:50,230 --> 00:45:48,599
in many cases science it progresses

922
00:45:52,730 --> 00:45:50,240
because we

923
00:45:56,930 --> 00:45:52,740
recognize that we've made some mistakes

924
00:46:01,430 --> 00:45:56,940
and we try to collect them and and by

925
00:46:04,250 --> 00:46:01,440
doing this the science goes on

926
00:46:06,710 --> 00:46:04,260
of course this way to deal with mistakes

927
00:46:09,710 --> 00:46:06,720
is not it's not the same for everybody

928
00:46:14,410 --> 00:46:09,720
as we unfortunately know

929
00:46:19,910 --> 00:46:17,329
we are in the second Canto of the

930
00:46:19,920 --> 00:46:22,809
uh

931
00:46:29,150 --> 00:46:25,309
had to leave

932
00:46:32,270 --> 00:46:29,160
his leader virgilio who led him

933
00:46:34,790 --> 00:46:32,280
through hell and through to Inferno and

934
00:46:38,809 --> 00:46:34,800
and purgatory

935
00:46:40,430 --> 00:46:38,819
uh because vigilio could not go beyond

936
00:46:43,970 --> 00:46:40,440
purgatory

937
00:46:47,750 --> 00:46:43,980
because he was not baptized

938
00:46:49,849 --> 00:46:47,760
um and so Dante had to find a new leader

939
00:46:53,630 --> 00:46:49,859
and

940
00:46:55,670 --> 00:46:53,640
he finds Beatrice of course this is not

941
00:46:56,270 --> 00:46:55,680
my chance

942
00:46:59,750 --> 00:46:56,280
um

943
00:47:03,109 --> 00:46:59,760
and you know starting his trip with

944
00:47:06,250 --> 00:47:04,190
um

945
00:47:13,030 --> 00:47:06,260
the first

946
00:47:17,990 --> 00:47:13,040
sky of the Moon

947
00:47:20,569 --> 00:47:18,000
uh and well you know the Moon

948
00:47:23,410 --> 00:47:20,579
had a big problem

949
00:47:26,270 --> 00:47:23,420
you know the Moon is the only

950
00:47:28,849 --> 00:47:26,280
uh Knight

951
00:47:32,270 --> 00:47:28,859
Sky body

952
00:47:35,870 --> 00:47:32,280
that you can distinguish I mean that you

953
00:47:39,950 --> 00:47:35,880
can resolve by naked eye

954
00:47:41,930 --> 00:47:39,960
uh and of course Dante only had naked

955
00:47:44,030 --> 00:47:41,940
eye there were no instruments except

956
00:47:46,430 --> 00:47:44,040
from the eye

957
00:47:54,109 --> 00:47:49,510
all the other bodies in the sky you know

958
00:47:56,870 --> 00:47:54,119
Mars Jupiter Saturday were all points

959
00:47:59,329 --> 00:47:56,880
the only thing that that

960
00:48:01,430 --> 00:47:59,339
done this I could resolve in the night

961
00:48:04,309 --> 00:48:01,440
sky is the Moon

962
00:48:06,050 --> 00:48:04,319
but the moon had a problem the moon had

963
00:48:07,190 --> 00:48:06,060
spots

964
00:48:09,109 --> 00:48:07,200
well

965
00:48:13,270 --> 00:48:09,119
how comes that

966
00:48:17,990 --> 00:48:13,280
they all told us that the sky is perfect

967
00:48:21,410 --> 00:48:18,000
you know circles spheres

968
00:48:24,170 --> 00:48:21,420
but the moments has spots but this is

969
00:48:26,510 --> 00:48:24,180
not perfect so how comes that

970
00:48:29,390 --> 00:48:26,520
and and of course Dante well takes the

971
00:48:33,170 --> 00:48:29,400
opportunity that he has Beatrice

972
00:48:35,450 --> 00:48:33,180
and so he asks him about the origin of

973
00:48:39,230 --> 00:48:35,460
of moon spots

974
00:48:43,690 --> 00:48:39,240
and you can see here he says he asked

975
00:48:49,069 --> 00:48:43,700
Beatrice please tell me what uh this

976
00:48:54,050 --> 00:48:49,079
dark spots on this body that people down

977
00:48:58,069 --> 00:48:54,060
on the earth uh think they are like the

978
00:48:59,870 --> 00:48:58,079
um the face of kaina

979
00:49:05,630 --> 00:48:59,880
well

980
00:49:07,609 --> 00:49:05,640
thought that the the moons the the moon

981
00:49:09,170 --> 00:49:07,619
spot represent the face of kaina well

982
00:49:12,650 --> 00:49:09,180
you can see on the moon spots whatever

983
00:49:13,970 --> 00:49:12,660
you like but so that was the question

984
00:49:15,650 --> 00:49:13,980
and

985
00:49:20,829 --> 00:49:15,660
so

986
00:49:27,650 --> 00:49:24,770
Smiles a bit

987
00:49:30,650 --> 00:49:27,660
now be careful when we reach our Smiles

988
00:49:34,190 --> 00:49:30,660
there is something important happening

989
00:49:36,530 --> 00:49:34,200
and and then Matthew goes on well

990
00:49:39,609 --> 00:49:36,540
beticia tries to answer and and the

991
00:49:42,349 --> 00:49:39,619
first thing she says is well be careful

992
00:49:46,430 --> 00:49:42,359
uh the first thing that comes to your

993
00:49:48,589 --> 00:49:46,440
mind is not necessarily the

994
00:49:51,290 --> 00:49:48,599
um the right one

995
00:49:55,309 --> 00:49:51,300
and then beat she does something that we

996
00:49:59,990 --> 00:49:55,319
all very much used to it because uh we

997
00:50:02,630 --> 00:50:00,000
all uh we've all been pupil some of us

998
00:50:05,109 --> 00:50:02,640
have been teacher you know when uh when

999
00:50:08,990 --> 00:50:05,119
a student asks his teacher a question

1000
00:50:11,210 --> 00:50:09,000
uh well often the teacher reverses the

1001
00:50:14,450 --> 00:50:11,220
the question to the to to the student

1002
00:50:15,650 --> 00:50:14,460
and so this is what what be a teacher

1003
00:50:25,870 --> 00:50:15,660
does

1004
00:50:32,030 --> 00:50:28,490
he has to say something

1005
00:50:35,089 --> 00:50:32,040
another says well

1006
00:50:38,870 --> 00:50:35,099
he says well I think that

1007
00:50:41,270 --> 00:50:38,880
what the the the the spots are the fact

1008
00:50:46,970 --> 00:50:41,280
that there are different densities

1009
00:50:55,370 --> 00:50:51,170
uh well this idea

1010
00:50:58,750 --> 00:50:55,380
is is an old idea so don't we first one

1011
00:51:02,329 --> 00:50:58,760
here over there is which was accepted by

1012
00:51:06,430 --> 00:51:02,339
Albert the Great and he also talks about

1013
00:51:09,770 --> 00:51:06,440
it in the convivio you see it is

1014
00:51:12,170 --> 00:51:09,780
means little density which which is

1015
00:51:15,530 --> 00:51:12,180
causing the the the

1016
00:51:17,210 --> 00:51:15,540
the spots in the Moon

1017
00:51:19,609 --> 00:51:17,220
well

1018
00:51:24,530 --> 00:51:19,619
and then he starts

1019
00:51:30,290 --> 00:51:28,309
and British starts by saying well

1020
00:51:35,210 --> 00:51:30,300
you long

1021
00:51:39,950 --> 00:51:35,220
telling you

1022
00:51:43,250 --> 00:51:41,510
uh

1023
00:51:48,410 --> 00:51:43,260
the first thing we are teacher does to

1024
00:51:52,370 --> 00:51:48,420
confuse the refute Dante's idea

1025
00:51:54,410 --> 00:51:52,380
is this she she refers to the the eight

1026
00:51:56,809 --> 00:51:54,420
sphere the eight sphere is the sphere

1027
00:52:00,290 --> 00:51:56,819
the fixed stars in fact she said the

1028
00:52:02,089 --> 00:52:00,300
eight sphere it shows you many lines

1029
00:52:04,130 --> 00:52:02,099
many stars

1030
00:52:05,510 --> 00:52:04,140
and in fact she says well

1031
00:52:08,089 --> 00:52:05,520
you know

1032
00:52:10,130 --> 00:52:08,099
the different stars in in the eight

1033
00:52:12,650 --> 00:52:10,140
sphere in

1034
00:52:14,569 --> 00:52:12,660
um have different brightness

1035
00:52:18,589 --> 00:52:14,579
now

1036
00:52:21,829 --> 00:52:18,599
if the different brightness of the Stars

1037
00:52:23,510 --> 00:52:21,839
were due to a different density as you

1038
00:52:27,349 --> 00:52:23,520
say for the moon spawns

1039
00:52:30,650 --> 00:52:27,359
then the Stars would have only one

1040
00:52:33,049 --> 00:52:30,660
quality one virtue

1041
00:52:36,470 --> 00:52:33,059
which is density

1042
00:52:40,130 --> 00:52:36,480
and this cannot be because every Star

1043
00:52:45,170 --> 00:52:40,140
has its own virtue which is transferred

1044
00:52:47,870 --> 00:52:45,180
from God to to humans

1045
00:52:51,230 --> 00:52:47,880
well of course this is an argument which

1046
00:52:54,290 --> 00:52:51,240
is theological philosophical but this is

1047
00:52:58,130 --> 00:52:54,300
the first argument that beat uses but

1048
00:53:02,809 --> 00:52:58,140
then she goes on and I invite you to to

1049
00:53:05,329 --> 00:53:02,819
read this whole Canto uh

1050
00:53:08,450 --> 00:53:05,339
because it's very interesting

1051
00:53:15,530 --> 00:53:11,270
Beatrice then

1052
00:53:18,950 --> 00:53:15,540
says the following thing

1053
00:53:22,849 --> 00:53:18,960
well if there are

1054
00:53:24,829 --> 00:53:22,859
dense region and less dense regions in

1055
00:53:29,990 --> 00:53:24,839
the moon and these are causing the moon

1056
00:53:33,950 --> 00:53:31,430
either

1057
00:53:37,930 --> 00:53:33,960
the dense regions

1058
00:53:41,390 --> 00:53:37,940
do not cover the whole face of the moon

1059
00:53:43,190 --> 00:53:41,400
or they cover it well that's quite

1060
00:53:46,790 --> 00:53:43,200
obvious

1061
00:53:50,450 --> 00:53:46,800
and then he said well the first case

1062
00:53:54,170 --> 00:53:50,460
that the dense regions do not cover the

1063
00:53:58,730 --> 00:53:54,180
whole face of the moon is not possible

1064
00:54:01,309 --> 00:53:58,740
because during an eclipse

1065
00:54:04,069 --> 00:54:01,319
um a solar eclipse you know in which in

1066
00:54:05,630 --> 00:54:04,079
which the the moon gets in front of the

1067
00:54:07,010 --> 00:54:05,640
Sun

1068
00:54:09,710 --> 00:54:07,020
uh

1069
00:54:12,410 --> 00:54:09,720
you would you would see the light of the

1070
00:54:14,150 --> 00:54:12,420
Sun going through this less dense

1071
00:54:15,710 --> 00:54:14,160
regions of the Moon that do not cover

1072
00:54:19,549 --> 00:54:15,720
the whole face

1073
00:54:23,030 --> 00:54:19,559
so it is not possible that the

1074
00:54:24,710 --> 00:54:23,040
less than three the the dense region do

1075
00:54:26,569 --> 00:54:24,720
not cover the whole face of the Moon the

1076
00:54:29,390 --> 00:54:26,579
dense region must cover the whole face

1077
00:54:31,670 --> 00:54:29,400
of the Moon that's clear

1078
00:54:33,770 --> 00:54:31,680
but then we are teacher says well you

1079
00:54:36,710 --> 00:54:33,780
you could think that

1080
00:54:38,930 --> 00:54:36,720
still the moon spots are caused by the

1081
00:54:42,710 --> 00:54:38,940
fact that the

1082
00:54:46,609 --> 00:54:42,720
the dense regions are different depths

1083
00:54:50,930 --> 00:54:46,619
inside the moon and that could cause the

1084
00:54:53,210 --> 00:54:50,940
um the moon spots in order to refute

1085
00:55:00,069 --> 00:54:53,220
even these other hypothesis so

1086
00:55:00,079 --> 00:55:05,049
does a thought experiment

1087
00:55:09,849 --> 00:55:08,569
experiment you know Einstein did the

1088
00:55:13,270 --> 00:55:09,859
same

1089
00:55:16,430 --> 00:55:13,280
centuries later in order to

1090
00:55:21,530 --> 00:55:16,440
explain his theories

1091
00:55:23,870 --> 00:55:21,540
so the third experiment that uh that

1092
00:55:30,230 --> 00:55:23,880
Beatrice is talking about is the

1093
00:55:36,049 --> 00:55:33,230
take three mirrors

1094
00:55:38,210 --> 00:55:36,059
you place two of those mirrors in front

1095
00:55:40,730 --> 00:55:38,220
of you at some distance

1096
00:55:44,270 --> 00:55:40,740
and

1097
00:55:48,710 --> 00:55:44,280
the third one you place it further

1098
00:55:50,809 --> 00:55:48,720
between the first two so at the larger

1099
00:55:53,750 --> 00:55:50,819
distance between the first two

1100
00:55:55,609 --> 00:55:53,760
and then you put a light

1101
00:55:57,950 --> 00:55:55,619
on your back

1102
00:55:59,569 --> 00:55:57,960
like a fire

1103
00:56:03,349 --> 00:55:59,579
um

1104
00:56:07,730 --> 00:56:03,359
a light something so that you can see

1105
00:56:13,430 --> 00:56:10,069
uh

1106
00:56:17,650 --> 00:56:13,440
and then in the end you see

1107
00:56:22,490 --> 00:56:17,660
in the end here she says well although

1108
00:56:26,569 --> 00:56:22,500
the image which you see reflected in in

1109
00:56:30,470 --> 00:56:26,579
the father mirror is smaller in size

1110
00:56:32,329 --> 00:56:30,480
than those that you see Factory into the

1111
00:56:37,069 --> 00:56:32,339
other two

1112
00:56:41,630 --> 00:56:37,079
still you will see shine in the same way

1113
00:56:48,109 --> 00:56:45,770
so this is for us astronomers is is is a

1114
00:56:49,849 --> 00:56:48,119
very clear thing it's the is the fact

1115
00:56:53,450 --> 00:56:49,859
that the

1116
00:56:56,150 --> 00:56:53,460
surface blindness of a of an object in

1117
00:56:58,430 --> 00:56:56,160
the sky does not depend on its distance

1118
00:57:01,609 --> 00:56:58,440
it's very clear the surface brightness

1119
00:57:03,530 --> 00:57:01,619
is the ratio between the Luminosity or

1120
00:57:06,650 --> 00:57:03,540
the total Luminosity of the object and

1121
00:57:08,930 --> 00:57:06,660
the solid angles obtained by the object

1122
00:57:11,329 --> 00:57:08,940
and since it's the ratio between these

1123
00:57:14,630 --> 00:57:11,339
two things and since both things

1124
00:57:17,870 --> 00:57:14,640
uh very uh inversely as a square root of

1125
00:57:22,069 --> 00:57:17,880
the distance the ratio is constant with

1126
00:57:27,710 --> 00:57:24,349
uh

1127
00:57:32,089 --> 00:57:29,870
there's something really wonderful

1128
00:57:34,849 --> 00:57:32,099
Happening Here something really

1129
00:57:39,170 --> 00:57:37,069
first

1130
00:57:41,210 --> 00:57:39,180
Dante

1131
00:57:44,809 --> 00:57:41,220
chooses

1132
00:57:47,390 --> 00:57:44,819
as his scientific Master a woman

1133
00:57:49,250 --> 00:57:47,400
beatricia

1134
00:57:53,630 --> 00:57:49,260
it will take

1135
00:57:55,970 --> 00:57:53,640
many centuries before a woman would be

1136
00:57:58,609 --> 00:57:55,980
accepted in science

1137
00:58:02,990 --> 00:57:58,619
you know maybe Marie Curie where you

1138
00:58:05,809 --> 00:58:03,000
tell me well Dante had already done it

1139
00:58:09,109 --> 00:58:05,819
second thing

1140
00:58:10,069 --> 00:58:09,119
Beatrice but it's it's Dante Who Lies Of

1141
00:58:13,609 --> 00:58:10,079
course

1142
00:58:17,329 --> 00:58:13,619
uses a gedanke experiments

1143
00:58:18,589 --> 00:58:17,339
in order to confute an idea

1144
00:58:20,569 --> 00:58:18,599
hmm

1145
00:58:22,490 --> 00:58:20,579
Einstein did the same many centuries

1146
00:58:27,120 --> 00:58:22,500
later

1147
00:58:32,809 --> 00:58:28,849
[Music]

1148
00:58:35,690 --> 00:58:32,819
talks about the constants of surface

1149
00:58:37,430 --> 00:58:35,700
brightness with distance

1150
00:58:41,089 --> 00:58:37,440
well

1151
00:58:42,650 --> 00:58:41,099
I think we can give Dante a PhD in

1152
00:58:46,250 --> 00:58:42,660
physics

1153
00:58:49,390 --> 00:58:46,260
well it's not a Nobel Prize

1154
00:58:57,289 --> 00:58:53,170
uh well this is an image of the thought

1155
00:58:59,930 --> 00:58:57,299
experiments you see the Observer the

1156
00:59:03,289 --> 00:58:59,940
three mirrors and the lamp in the back

1157
00:59:07,549 --> 00:59:03,299
well the light in the back

1158
00:59:10,130 --> 00:59:07,559
okay uh let's get on to my last

1159
00:59:12,470 --> 00:59:10,140
argument for tonight

1160
00:59:14,630 --> 00:59:12,480
it's about the whole structure of the

1161
00:59:17,030 --> 00:59:14,640
universe of Dante's universe

1162
00:59:19,609 --> 00:59:17,040
well we know the structure of Dante's

1163
00:59:22,370 --> 00:59:19,619
Universe starts from the polymeric

1164
00:59:25,190 --> 00:59:22,380
system we already said that the Earth is

1165
00:59:26,589 --> 00:59:25,200
at the center of the universe and then

1166
00:59:29,690 --> 00:59:26,599
there are

1167
00:59:33,950 --> 00:59:29,700
nine spheres above the Earth

1168
00:59:37,250 --> 00:59:33,960
the moon Mercury Venus the sun Mars

1169
00:59:41,210 --> 00:59:37,260
Jupiter Saturn the fixed stars and the

1170
00:59:44,870 --> 00:59:41,220
Primo mobile the prime mover

1171
00:59:46,490 --> 00:59:44,880
um which is you know all these

1172
00:59:49,430 --> 00:59:46,500
um

1173
00:59:51,470 --> 00:59:49,440
spheres around the Earth are turning

1174
00:59:53,630 --> 00:59:51,480
faster and faster

1175
00:59:55,430 --> 00:59:53,640
and the Primo mobile is the fastest

1176
00:59:58,250 --> 00:59:55,440
turning one and in fact it was called

1177
01:00:01,010 --> 00:59:58,260
prime mover because it was thought that

1178
01:00:02,510 --> 01:00:01,020
he would give the movement to all the

1179
01:00:03,890 --> 01:00:02,520
others

1180
01:00:05,770 --> 01:00:03,900
then

1181
01:00:09,710 --> 01:00:05,780
at the

1182
01:00:12,950 --> 01:00:09,720
end of the 27th Canto of the paradise

1183
01:00:15,890 --> 01:00:12,960
Dante and Beatrice get to this

1184
01:00:16,849 --> 01:00:15,900
Primo mobilities prime mover and they

1185
01:00:23,390 --> 01:00:16,859
look

1186
01:00:24,609 --> 01:00:23,400
and they see something symmetric

1187
01:00:29,450 --> 01:00:24,619
another

1188
01:00:31,549 --> 01:00:29,460
nine spheres the the Angelic circles

1189
01:00:33,829 --> 01:00:31,559
actually spheres

1190
01:00:36,230 --> 01:00:33,839
and at the center of one inside the

1191
01:00:40,970 --> 01:00:36,240
other and at the center of them there is

1192
01:00:40,980 --> 01:00:45,170
well

1193
01:00:49,670 --> 01:00:47,690
this structure

1194
01:00:52,730 --> 01:00:49,680
it made

1195
01:00:57,170 --> 01:00:54,170
uh

1196
01:01:00,890 --> 01:00:57,180
think that this structure is very

1197
01:01:03,829 --> 01:01:00,900
similar to Einstein's hydrosphere you

1198
01:01:06,130 --> 01:01:03,839
know I say I just see is the

1199
01:01:08,990 --> 01:01:06,140
is the way

1200
01:01:12,230 --> 01:01:09,000
that the universe is structured in

1201
01:01:17,530 --> 01:01:14,870
um the first person to think about it

1202
01:01:19,069 --> 01:01:17,540
was a Swiss guy

1203
01:01:23,150 --> 01:01:19,079
mathematician and physicist

1204
01:01:25,910 --> 01:01:23,160
mathematician Andreas paiser in 1925 he

1205
01:01:28,069 --> 01:01:25,920
wrote about this about the similarity of

1206
01:01:30,710 --> 01:01:28,079
the structure of Tantus Universe with

1207
01:01:35,650 --> 01:01:30,720
the with high side atmosphere

1208
01:01:37,309 --> 01:01:35,660
you know not many years after

1209
01:01:39,530 --> 01:01:37,319
Einstein's

1210
01:01:43,010 --> 01:01:39,540
general relativity

1211
01:01:46,789 --> 01:01:43,020
but there is a very beautiful article

1212
01:01:49,450 --> 01:01:46,799
which I recommend you to read by Mark

1213
01:01:51,829 --> 01:01:49,460
Peterson an American

1214
01:01:54,230 --> 01:01:51,839
mathematician and physicist

1215
01:01:57,770 --> 01:01:54,240
the this article is in the American

1216
01:02:00,410 --> 01:01:57,780
Journal of physics in in use with me he

1217
01:02:03,170 --> 01:02:00,420
was published in 1979

1218
01:02:06,109 --> 01:02:03,180
and this figure actually comes from that

1219
01:02:08,210 --> 01:02:06,119
article you see this is the Ptolemy

1220
01:02:12,109 --> 01:02:08,220
Universe with the Earth at the center

1221
01:02:14,690 --> 01:02:12,119
and the nine spheres around it

1222
01:02:18,890 --> 01:02:14,700
and he is a symmetric

1223
01:02:20,630 --> 01:02:18,900
thing which is which is beyond the prime

1224
01:02:23,690 --> 01:02:20,640
mover

1225
01:02:26,510 --> 01:02:23,700
you see it's very symmetric

1226
01:02:29,089 --> 01:02:26,520
actually this point p

1227
01:02:32,210 --> 01:02:29,099
is the point where

1228
01:02:33,589 --> 01:02:32,220
Dante and Beatrice get to the Primo

1229
01:02:37,549 --> 01:02:33,599
mobile

1230
01:02:39,049 --> 01:02:37,559
and at the end of the 27th scant of the

1231
01:02:41,390 --> 01:02:39,059
paradise

1232
01:02:43,490 --> 01:02:41,400
Dante says

1233
01:02:47,510 --> 01:02:43,500
about this point

1234
01:02:52,670 --> 01:02:47,520
he says I cannot tell you

1235
01:02:56,690 --> 01:02:52,680
which place Beatrice choosed

1236
01:03:01,130 --> 01:02:56,700
for us so this point

1237
01:03:03,289 --> 01:03:01,140
so it doesn't matter where they got to

1238
01:03:04,970 --> 01:03:03,299
the Prima Mobility

1239
01:03:08,870 --> 01:03:04,980
what they would see on the other side

1240
01:03:14,150 --> 01:03:10,849
uh

1241
01:03:20,890 --> 01:03:15,950
you see the question on the top how

1242
01:03:26,030 --> 01:03:23,809
this is a question that we would like to

1243
01:03:28,910 --> 01:03:26,040
understand I think it's an important

1244
01:03:34,130 --> 01:03:31,670
how could he think something that is

1245
01:03:36,410 --> 01:03:34,140
similar to an atmosphere

1246
01:03:39,049 --> 01:03:36,420
and I think that the

1247
01:03:41,750 --> 01:03:39,059
the answer to this

1248
01:03:44,809 --> 01:03:41,760
deals with the fact that

1249
01:03:47,750 --> 01:03:44,819
uh spherical geometry at the times of

1250
01:03:51,230 --> 01:03:47,760
Dante was very well known

1251
01:03:54,349 --> 01:03:51,240
was even maybe better known that than

1252
01:03:57,349 --> 01:03:54,359
euclidean geometry

1253
01:03:58,490 --> 01:03:57,359
uh you know you clean a geometry deals

1254
01:04:00,829 --> 01:03:58,500
about

1255
01:04:02,589 --> 01:04:00,839
uh

1256
01:04:09,309 --> 01:04:02,599
um parallels

1257
01:04:12,109 --> 01:04:09,319
deals with the square angles deals with

1258
01:04:14,150 --> 01:04:12,119
Pythagoras trm

1259
01:04:16,190 --> 01:04:14,160
and so on

1260
01:04:17,210 --> 01:04:16,200
spherical geometry is completely

1261
01:04:21,670 --> 01:04:17,220
different

1262
01:04:24,890 --> 01:04:21,680
geometries for example is the geometry

1263
01:04:27,770 --> 01:04:24,900
on the surface of a sphere now on the

1264
01:04:30,410 --> 01:04:27,780
surface of a sphere uh

1265
01:04:31,609 --> 01:04:30,420
you don't have parallels there are no

1266
01:04:34,010 --> 01:04:31,619
parallels

1267
01:04:36,530 --> 01:04:34,020
uh

1268
01:04:40,730 --> 01:04:36,540
um full circles

1269
01:04:43,670 --> 01:04:40,740
always have two points in common so

1270
01:04:46,549 --> 01:04:43,680
there are no parallels the Pythagorean

1271
01:04:47,809 --> 01:04:46,559
theorem does not hold on the surface of

1272
01:04:49,430 --> 01:04:47,819
the sphere so it's a completely

1273
01:04:52,910 --> 01:04:49,440
different geometry

1274
01:04:55,430 --> 01:04:52,920
and it was well known at the time was

1275
01:05:00,109 --> 01:04:55,440
done because they knew

1276
01:05:03,370 --> 01:05:00,119
that sphere is where we live is where we

1277
01:05:09,230 --> 01:05:03,380
travel is where we build

1278
01:05:09,770 --> 01:05:09,240
so it was important because of this more

1279
01:05:12,490 --> 01:05:09,780
um

1280
01:05:17,270 --> 01:05:12,500
so also

1281
01:05:19,549 --> 01:05:17,280
Dante had as a master Brunetto latini

1282
01:05:22,849 --> 01:05:19,559
Brit latini was it was a teacher of

1283
01:05:26,690 --> 01:05:22,859
Dante and he had written a book

1284
01:05:28,970 --> 01:05:26,700
uh the the treasure this book had been

1285
01:05:30,230 --> 01:05:28,980
written both in Italian and in old

1286
01:05:32,809 --> 01:05:30,240
French

1287
01:05:35,569 --> 01:05:32,819
and it's a sort of an encyclopedic book

1288
01:05:38,870 --> 01:05:35,579
it deals with many different things and

1289
01:05:41,569 --> 01:05:38,880
it also deals with spherical geometry

1290
01:05:44,870 --> 01:05:41,579
now how does he deal with it

1291
01:05:48,049 --> 01:05:44,880
he deals with it not by looking at a

1292
01:05:50,750 --> 01:05:48,059
sphere from outside but by being on a

1293
01:05:55,549 --> 01:05:50,760
sphere which is what we do every day and

1294
01:05:58,250 --> 01:05:55,559
he says well take two Riders on a horse

1295
01:06:01,309 --> 01:05:58,260
starting from the same point of a

1296
01:06:02,210 --> 01:06:01,319
spherical or surface of a sphere say the

1297
01:06:05,510 --> 01:06:02,220
Earth

1298
01:06:07,730 --> 01:06:05,520
and they they start from same point into

1299
01:06:11,030 --> 01:06:07,740
different directions

1300
01:06:12,950 --> 01:06:11,040
so what happens is that they

1301
01:06:15,589 --> 01:06:12,960
travel they travel they travel forget

1302
01:06:17,930 --> 01:06:15,599
about mountains and seas doesn't matter

1303
01:06:21,109 --> 01:06:17,940
they travel travel and then they meet

1304
01:06:23,030 --> 01:06:21,119
again on the opposite side of the earth

1305
01:06:25,730 --> 01:06:23,040
if they travel

1306
01:06:27,170 --> 01:06:25,740
father they would meet again at the

1307
01:06:30,289 --> 01:06:27,180
starting point

1308
01:06:32,150 --> 01:06:30,299
so this is something very simple the

1309
01:06:35,630 --> 01:06:32,160
Dante could very well understand

1310
01:06:38,630 --> 01:06:35,640
Brunetto latini and explain this to

1311
01:06:43,190 --> 01:06:38,640
Dante it's very easy to understand now

1312
01:06:46,910 --> 01:06:43,200
let's take this other example let's take

1313
01:06:48,349 --> 01:06:46,920
two Riders two men two aunts whatever

1314
01:06:53,210 --> 01:06:48,359
you like

1315
01:06:55,490 --> 01:06:53,220
leaving from the South Pole of the Earth

1316
01:06:57,190 --> 01:06:55,500
from a sample

1317
01:07:01,430 --> 01:06:57,200
well

1318
01:07:03,910 --> 01:07:01,440
whichever direction he he lives

1319
01:07:07,549 --> 01:07:03,920
he would go north he can only go north

1320
01:07:11,109 --> 01:07:07,559
and what happens when he goes north

1321
01:07:15,950 --> 01:07:14,210
Circles of increasing sign you know

1322
01:07:19,970 --> 01:07:15,960
parallels

1323
01:07:23,150 --> 01:07:19,980
of increasing size until he reaches the

1324
01:07:27,410 --> 01:07:23,160
largest one which is the equator

1325
01:07:29,150 --> 01:07:27,420
now if you put a parallel every 10

1326
01:07:31,250 --> 01:07:29,160
degrees

1327
01:07:32,089 --> 01:07:31,260
from a South Pole to the equator you

1328
01:07:33,890 --> 01:07:32,099
would have

1329
01:07:36,170 --> 01:07:33,900
you cross

1330
01:07:39,349 --> 01:07:36,180
nine parallels

1331
01:07:43,849 --> 01:07:39,359
just like the nine Skies that the

1332
01:07:45,770 --> 01:07:43,859
Dante close to which the primobita

1333
01:07:47,390 --> 01:07:45,780
going further

1334
01:07:50,650 --> 01:07:47,400
from the equator

1335
01:07:55,789 --> 01:07:50,660
The Traveler would cross

1336
01:07:59,930 --> 01:07:55,799
Circles of decreasing size until he gets

1337
01:08:01,849 --> 01:07:59,940
to one point the North Pole hmm

1338
01:08:04,609 --> 01:08:01,859
so

1339
01:08:07,430 --> 01:08:04,619
what I'm telling you is very easy very

1340
01:08:10,730 --> 01:08:07,440
simple Dante could very well understand

1341
01:08:14,150 --> 01:08:10,740
this no problem

1342
01:08:16,130 --> 01:08:14,160
so what Dante has done to think about

1343
01:08:20,749 --> 01:08:16,140
the structure of his Universe he has

1344
01:08:25,550 --> 01:08:20,759
used the same example the same thing

1345
01:08:29,749 --> 01:08:25,560
by increasing it by one dimension

1346
01:08:32,390 --> 01:08:29,759
so he starts from

1347
01:08:34,669 --> 01:08:32,400
from the Earth

1348
01:08:37,189 --> 01:08:34,679
crosses

1349
01:08:39,470 --> 01:08:37,199
not Nine Circles nine spheres because

1350
01:08:41,390 --> 01:08:39,480
there is one additional Dimension until

1351
01:08:43,370 --> 01:08:41,400
the largest one

1352
01:08:45,829 --> 01:08:43,380
the Prima mobile

1353
01:08:47,630 --> 01:08:45,839
and after that there are other nine

1354
01:08:51,349 --> 01:08:47,640
spheres

1355
01:08:52,910 --> 01:08:51,359
smaller one inside the other

1356
01:08:54,349 --> 01:08:52,920
until

1357
01:08:56,829 --> 01:08:54,359
the point

1358
01:08:59,930 --> 01:08:56,839
luminous point which is God

1359
01:09:02,930 --> 01:08:59,940
so you see the way

1360
01:09:05,090 --> 01:09:02,940
I'm telling you this

1361
01:09:07,249 --> 01:09:05,100
is quite clear

1362
01:09:09,950 --> 01:09:07,259
that Dante could do it and he has done

1363
01:09:11,090 --> 01:09:09,960
it this is what Dante has done it has

1364
01:09:14,510 --> 01:09:11,100
done

1365
01:09:17,209 --> 01:09:14,520
of course he could not know and he did

1366
01:09:19,970 --> 01:09:17,219
not know that this would be

1367
01:09:23,269 --> 01:09:19,980
would become Einstein's hypersphere no

1368
01:09:25,930 --> 01:09:23,279
he didn't know that he doesn't tell him

1369
01:09:29,090 --> 01:09:25,940
of course he only

1370
01:09:31,550 --> 01:09:29,100
centuries later we couldn't we could

1371
01:09:34,070 --> 01:09:31,560
guess about the similarities but that's

1372
01:09:36,410 --> 01:09:34,080
not important but Dante could do it and

1373
01:09:38,209 --> 01:09:36,420
he has done it

1374
01:09:41,870 --> 01:09:38,219
okay

1375
01:09:46,070 --> 01:09:41,880
um well some details

1376
01:09:50,209 --> 01:09:46,080
uh the article by Mark Peterson about

1377
01:09:53,030 --> 01:09:50,219
the similarity of Einstein Dante

1378
01:09:54,350 --> 01:09:53,040
Universe structure and Einstein office

1379
01:09:57,229 --> 01:09:54,360
here

1380
01:10:00,110 --> 01:09:57,239
well starts by saying poetry and physics

1381
01:10:02,510 --> 01:10:00,120
are similar in the universe of course

1382
01:10:05,930 --> 01:10:02,520
then there is the there is the equation

1383
01:10:08,870 --> 01:10:05,940
of the atmosphere who have known the ABC

1384
01:10:10,790 --> 01:10:08,880
is a is a is a three-dimensional sphere

1385
01:10:12,470 --> 01:10:10,800
in a four-dimensional space and the

1386
01:10:14,110 --> 01:10:12,480
equation is like this it's like the

1387
01:10:17,150 --> 01:10:14,120
equation of a sphere with an additional

1388
01:10:18,770 --> 01:10:17,160
with an additional item there is there

1389
01:10:21,470 --> 01:10:18,780
is a fourth dimension

1390
01:10:24,050 --> 01:10:21,480
in that case the fourth dimension is

1391
01:10:29,350 --> 01:10:24,060
rotation velocity

1392
01:10:32,450 --> 01:10:29,360
because in Einsteins this is time

1393
01:10:33,310 --> 01:10:32,460
multiplied by the velocity of light is a

1394
01:10:42,050 --> 01:10:33,320
is

1395
01:10:43,490 --> 01:10:42,060
ad does not talk about time but he has a

1396
01:10:47,450 --> 01:10:43,500
fourth dimension which is rotation

1397
01:10:48,910 --> 01:10:47,460
velocity in fact the Earth is standing

1398
01:10:53,990 --> 01:10:48,920
still

1399
01:10:56,830 --> 01:10:54,000
all the nine sky telemian sky is above

1400
01:10:59,870 --> 01:10:56,840
it they turn around it faster and faster

1401
01:11:03,530 --> 01:10:59,880
and the

1402
01:11:05,870 --> 01:11:03,540
the uh the Angelic circles the Angelic

1403
01:11:08,630 --> 01:11:05,880
spheres they keep turning faster and

1404
01:11:10,430 --> 01:11:08,640
faster so the the rotation velocity is a

1405
01:11:12,350 --> 01:11:10,440
coordinate which increases from the

1406
01:11:17,090 --> 01:11:12,360
Earth to to God

1407
01:11:20,149 --> 01:11:17,100
uniformly so that dances four dimension

1408
01:11:24,350 --> 01:11:20,159
uh well let's skip this if you want you

1409
01:11:28,729 --> 01:11:24,360
you can read it in in in Matt Peterson

1410
01:11:30,950 --> 01:11:28,739
paper yeah I want to end this by telling

1411
01:11:34,910 --> 01:11:33,169
a few things

1412
01:11:38,510 --> 01:11:34,920
well

1413
01:11:40,610 --> 01:11:38,520
the structure of Dante's Universe solves

1414
01:11:42,350 --> 01:11:40,620
quite a few problems that were quite

1415
01:11:44,270 --> 01:11:42,360
severe at the time

1416
01:11:45,830 --> 01:11:44,280
well one of these problems was the fact

1417
01:11:47,810 --> 01:11:45,840
that the

1418
01:11:50,209 --> 01:11:47,820
Dolomite universe

1419
01:11:53,090 --> 01:11:50,219
at the Earth at the center of the

1420
01:11:56,930 --> 01:11:53,100
universe and you know at the end at the

1421
01:12:01,130 --> 01:11:56,940
center of the earth you have Lucifer

1422
01:12:04,070 --> 01:12:01,140
so having a universe which has a the

1423
01:12:06,169 --> 01:12:04,080
center Lucifer is not something that

1424
01:12:09,950 --> 01:12:06,179
they liked

1425
01:12:12,709 --> 01:12:09,960
uh in that structure at least well the

1426
01:12:14,810 --> 01:12:12,719
universe has two centers

1427
01:12:17,330 --> 01:12:14,820
on one side there's the Earth with

1428
01:12:18,470 --> 01:12:17,340
Lucifer but at the other side there is a

1429
01:12:20,930 --> 01:12:18,480
black spot

1430
01:12:24,110 --> 01:12:20,940
which is God

1431
01:12:27,470 --> 01:12:24,120
so that was a problem an important

1432
01:12:29,270 --> 01:12:27,480
problem solved by Dante's Universe

1433
01:12:30,169 --> 01:12:29,280
structure

1434
01:12:33,050 --> 01:12:30,179
um

1435
01:12:35,450 --> 01:12:33,060
the other thing you know they you would

1436
01:12:41,209 --> 01:12:35,460
people at the time were asking questions

1437
01:12:43,370 --> 01:12:41,219
well like well is God inside or outside

1438
01:12:52,669 --> 01:12:43,380
the universe

1439
01:12:54,050 --> 01:12:52,679
you know these are quite important

1440
01:12:57,709 --> 01:12:54,060
questions

1441
01:13:00,770 --> 01:12:57,719
well Dante has sold it

1442
01:13:02,590 --> 01:13:00,780
because clearly God is inside the

1443
01:13:06,830 --> 01:13:02,600
universe

1444
01:13:09,290 --> 01:13:06,840
he gets there

1445
01:13:10,669 --> 01:13:09,300
so the God is inside the universe and

1446
01:13:13,729 --> 01:13:10,679
what is outside

1447
01:13:15,790 --> 01:13:13,739
well there's nothing nothing outside the

1448
01:13:22,250 --> 01:13:15,800
universe

1449
01:13:25,810 --> 01:13:22,260
well um I can explain this to you well

1450
01:13:29,750 --> 01:13:25,820
I tried to do it in two ways well first

1451
01:13:34,430 --> 01:13:29,760
let's get one dimension back

1452
01:13:37,610 --> 01:13:34,440
think that we are two-dimensional beings

1453
01:13:39,470 --> 01:13:37,620
living in a two-dimensional world and

1454
01:13:43,010 --> 01:13:39,480
our two-dimensional word is the surface

1455
01:13:47,570 --> 01:13:44,770
now

1456
01:13:49,310 --> 01:13:47,580
uh our word

1457
01:13:51,709 --> 01:13:49,320
is clearly

1458
01:13:54,470 --> 01:13:51,719
Unlimited

1459
01:13:58,130 --> 01:13:54,480
because we can travel

1460
01:14:00,110 --> 01:13:58,140
through it without finding any limits

1461
01:14:01,550 --> 01:14:00,120
we can go on traveling and there is no

1462
01:14:04,910 --> 01:14:01,560
limit

1463
01:14:07,790 --> 01:14:04,920
but it's finite because the surface of a

1464
01:14:10,189 --> 01:14:07,800
sphere is a certain

1465
01:14:13,490 --> 01:14:10,199
finite surface

1466
01:14:15,410 --> 01:14:13,500
so unlimited and finite

1467
01:14:18,050 --> 01:14:15,420
and what's outside it there's nothing

1468
01:14:19,910 --> 01:14:18,060
because we are two-dimensional this is

1469
01:14:24,110 --> 01:14:19,920
our two-dimensional word and outside

1470
01:14:30,890 --> 01:14:26,689
um you know

1471
01:14:35,209 --> 01:14:30,900
our view of the universe

1472
01:14:41,590 --> 01:14:35,219
is that our universe started

1473
01:14:45,290 --> 01:14:41,600
in in a singularity which happened 30

1474
01:14:48,050 --> 01:14:45,300
13.6 billion years ago

1475
01:14:50,270 --> 01:14:48,060
uh some people call it Big Bang but it's

1476
01:14:51,770 --> 01:14:50,280
not a bang it's not an explosion it's a

1477
01:14:55,189 --> 01:14:51,780
singularity

1478
01:14:56,590 --> 01:14:55,199
space and time started at that point and

1479
01:15:01,130 --> 01:14:56,600
at that time

1480
01:15:05,630 --> 01:15:01,140
and then the universe expanded and you

1481
01:15:10,310 --> 01:15:05,640
know you get uh Stars galaxies Etc

1482
01:15:14,510 --> 01:15:13,189
and we're outside there's nothing I mean

1483
01:15:17,390 --> 01:15:14,520
if you

1484
01:15:18,910 --> 01:15:17,400
uh

1485
01:15:24,830 --> 01:15:18,920
the

1486
01:15:26,470 --> 01:15:24,840
so if you take a sphere

1487
01:15:28,970 --> 01:15:26,480
which is

1488
01:15:32,270 --> 01:15:28,980
13.6 billion

1489
01:15:36,470 --> 01:15:32,280
light years large

1490
01:15:43,189 --> 01:15:41,630
well there can be nothing outside that

1491
01:15:45,050 --> 01:15:43,199
okay

1492
01:15:47,990 --> 01:15:45,060
um

1493
01:15:51,110 --> 01:15:48,000
I think I learned here uh just by

1494
01:15:54,890 --> 01:15:51,120
telling you that the astronomical

1495
01:15:58,390 --> 01:15:54,900
arguments that I have told you in

1496
01:16:00,110 --> 01:15:58,400
Dante's Divine Comedy only a few of them

1497
01:16:00,850 --> 01:16:00,120
uh

1498
01:16:04,189 --> 01:16:00,860
um

1499
01:16:07,970 --> 01:16:04,199
about one and a half years ago I wrote a

1500
01:16:12,050 --> 01:16:07,980
book with Massimo capacioli about

1501
01:16:15,709 --> 01:16:12,060
trying to deal about all these arguments

1502
01:16:19,669 --> 01:16:15,719
it's in Italian but then we wrote an

1503
01:16:22,850 --> 01:16:19,679
English version of of the book which is

1504
01:16:24,010 --> 01:16:22,860
which you can see here created by word

1505
01:16:27,410 --> 01:16:24,020
scientific

1506
01:16:29,930 --> 01:16:27,420
and so if you are interested in knowing

1507
01:16:32,990 --> 01:16:29,940
about the other Atomic arguments The

1508
01:16:36,350 --> 01:16:33,000
Divine Comedy you can read them here

1509
01:16:38,169 --> 01:16:36,360
and I want to end by the last verse of

1510
01:16:43,070 --> 01:16:38,179
the Divine Comedy Lamour

1511
01:16:48,709 --> 01:16:46,250
thank you thank you so much spirulo

1512
01:16:50,930 --> 01:16:48,719
um that was

1513
01:16:54,590 --> 01:16:50,940
for someone who has not

1514
01:16:59,870 --> 01:16:54,600
um gone into uh The Divine Comedy as

1515
01:17:02,270 --> 01:16:59,880
deeply uh quite enlightening from uh the

1516
01:17:05,149 --> 01:17:02,280
um I don't know the the the the journey

1517
01:17:07,010 --> 01:17:05,159
that starts out is going

1518
01:17:09,050 --> 01:17:07,020
um I don't know kind of like Jules Verne

1519
01:17:12,470 --> 01:17:09,060
Journey to the Center of the Earth but

1520
01:17:14,990 --> 01:17:12,480
then transforms into a journey across

1521
01:17:17,570 --> 01:17:15,000
the uh Across the Universe and such

1522
01:17:20,330 --> 01:17:17,580
um that um you know certainly opened my

1523
01:17:21,410 --> 01:17:20,340
eyes to to what um what we're seeing

1524
01:17:24,010 --> 01:17:21,420
here

1525
01:17:26,630 --> 01:17:24,020
mm-hmm thank you

1526
01:17:29,209 --> 01:17:26,640
I don't know if if you foresee that

1527
01:17:31,729 --> 01:17:29,219
there could be questions or

1528
01:17:34,209 --> 01:17:31,739
we expect there will be questions I

1529
01:17:37,130 --> 01:17:34,219
always ask the first question

1530
01:17:39,709 --> 01:17:37,140
and so my first question

1531
01:17:42,950 --> 01:17:39,719
um I have to deal with um yeah actually

1532
01:17:45,590 --> 01:17:42,960
the variety of the

1533
01:17:46,910 --> 01:17:45,600
um things that that I I sort of sparked

1534
01:17:49,550 --> 01:17:46,920
on

1535
01:17:53,090 --> 01:17:49,560
um in terms of things because you talk

1536
01:17:54,649 --> 01:17:53,100
about uh in this is a 12th century book

1537
01:17:56,209 --> 01:17:54,659
um but he's talking about uh you're

1538
01:17:57,890 --> 01:17:56,219
mentioning the Earth as a sphere and

1539
01:18:00,770 --> 01:17:57,900
sort of accepting the idea that the

1540
01:18:03,590 --> 01:18:00,780
Earth is a sphere when you know in in

1541
01:18:06,590 --> 01:18:03,600
history we sort of think that

1542
01:18:09,770 --> 01:18:06,600
um as being a

1543
01:18:11,570 --> 01:18:09,780
something that uh happened much later

1544
01:18:13,910 --> 01:18:11,580
during the Renaissance

1545
01:18:16,669 --> 01:18:13,920
um so it sort of has allegories as I

1546
01:18:20,930 --> 01:18:16,679
said Jules Verne earlier but also to uh

1547
01:18:22,370 --> 01:18:20,940
Galileo uh in touch and it it when you

1548
01:18:23,930 --> 01:18:22,380
think of it when you mentioned him as a

1549
01:18:26,149 --> 01:18:23,940
genius it really

1550
01:18:28,850 --> 01:18:26,159
um the parallels across history were

1551
01:18:30,169 --> 01:18:28,860
were extremely strong to me

1552
01:18:32,050 --> 01:18:30,179
um and I was just wondering what your

1553
01:18:36,590 --> 01:18:32,060
thoughts are on that

1554
01:18:40,729 --> 01:18:36,600
well the the fact that the the Earth is

1555
01:18:42,410 --> 01:18:40,739
a sphere actually was known uh by the

1556
01:18:43,250 --> 01:18:42,420
Greeks

1557
01:18:45,709 --> 01:18:43,260
um

1558
01:18:48,590 --> 01:18:45,719
I think

1559
01:18:53,390 --> 01:18:48,600
I may be wrong but it was

1560
01:18:55,430 --> 01:18:53,400
maybe parcos or or a Greek guy who

1561
01:19:00,290 --> 01:18:55,440
measured actually measured the the

1562
01:19:04,910 --> 01:19:00,300
radius of the Earth by noticing that the

1563
01:19:09,590 --> 01:19:04,920
that in in the same day like the um some

1564
01:19:13,310 --> 01:19:09,600
Equinox the the sun would get to the

1565
01:19:14,770 --> 01:19:13,320
bottom of uh of a well in Aswan in the

1566
01:19:20,030 --> 01:19:14,780
southern Egypt

1567
01:19:23,330 --> 01:19:20,040
and would actually uh not be vertical in

1568
01:19:27,050 --> 01:19:23,340
in in the northern part of Egypt or in

1569
01:19:29,750 --> 01:19:27,060
Greece and by uh by the different in

1570
01:19:31,970 --> 01:19:29,760
angle of the Sun to the surface of the

1571
01:19:34,010 --> 01:19:31,980
Earth and the distance of the two points

1572
01:19:36,470 --> 01:19:34,020
he could measure the the radius of the

1573
01:19:38,570 --> 01:19:36,480
Earth quite accurately actually so it

1574
01:19:41,990 --> 01:19:38,580
was well known that the Earth was ground

1575
01:19:44,870 --> 01:19:42,000
what else did you say a lot of that

1576
01:19:48,590 --> 01:19:44,880
knowledge was lost well into the Middle

1577
01:19:50,570 --> 01:19:48,600
Ages so no no well

1578
01:19:52,610 --> 01:19:50,580
it's yeah

1579
01:19:56,510 --> 01:19:52,620
some of that knowledge was lost

1580
01:19:59,689 --> 01:19:56,520
definitely uh the when when the Library

1581
01:20:02,630 --> 01:19:59,699
of Alexandria burn and uh after that but

1582
01:20:05,390 --> 01:20:02,640
he went back to Europe through the Arabs

1583
01:20:06,410 --> 01:20:05,400
and but I'm sure that the actually the

1584
01:20:09,050 --> 01:20:06,420
knowledge

1585
01:20:11,570 --> 01:20:09,060
of the Earth being round was never

1586
01:20:14,209 --> 01:20:11,580
really lost even in the west what what

1587
01:20:17,270 --> 01:20:14,219
they didn't know and what Galileo

1588
01:20:20,330 --> 01:20:17,280
and others Kepler

1589
01:20:21,770 --> 01:20:20,340
um dealt with was was the fact that the

1590
01:20:23,930 --> 01:20:21,780
Earth is not at the center of the

1591
01:20:25,850 --> 01:20:23,940
universe there was the Sun so that

1592
01:20:28,689 --> 01:20:25,860
that's but that's another another

1593
01:20:31,490 --> 01:20:28,699
argument and the the

1594
01:20:35,030 --> 01:20:31,500
sphericity of the Earth was known

1595
01:20:37,310 --> 01:20:35,040
okay well also the um the variations of

1596
01:20:40,550 --> 01:20:37,320
the moon is uh striking with uh the

1597
01:20:42,530 --> 01:20:40,560
Galileo observations that uh uh of the

1598
01:20:44,390 --> 01:20:42,540
Luna Mare and the variations of the Moon

1599
01:20:48,290 --> 01:20:44,400
that was another one of the parallels

1600
01:20:51,590 --> 01:20:48,300
that I I had seen on this

1601
01:20:53,870 --> 01:20:51,600
um let's see uh Grant has been

1602
01:20:55,250 --> 01:20:53,880
monitoring the chat more closely than I

1603
01:20:56,209 --> 01:20:55,260
have

1604
01:20:58,729 --> 01:20:56,219
um

1605
01:21:00,050 --> 01:20:58,739
can we Grant and do you want to turn on

1606
01:21:02,750 --> 01:21:00,060
your video and see if we have any

1607
01:21:03,950 --> 01:21:02,760
questions from our YouTube chat yeah

1608
01:21:06,290 --> 01:21:03,960
absolutely

1609
01:21:08,990 --> 01:21:06,300
um I've got one to start us off which I

1610
01:21:10,790 --> 01:21:09,000
like which is uh especially in the time

1611
01:21:12,169 --> 01:21:10,800
of Dante there are a lot of things that

1612
01:21:13,910 --> 01:21:12,179
he was thinking about Frank kind of

1613
01:21:17,870 --> 01:21:13,920
mentioned that we kind of take for

1614
01:21:20,709 --> 01:21:17,880
granted what kind of Technology would he

1615
01:21:26,810 --> 01:21:20,719
have had to have these sort of

1616
01:21:31,090 --> 01:21:28,669
what

1617
01:21:38,410 --> 01:21:34,070
very little technology would be none in

1618
01:21:42,110 --> 01:21:38,420
the sense that uh in terms of

1619
01:21:44,810 --> 01:21:42,120
aids to the eye there was none so they

1620
01:21:48,169 --> 01:21:44,820
they would look at the stars of the

1621
01:21:50,630 --> 01:21:48,179
planets yeah the Sky by the naked eye

1622
01:21:53,810 --> 01:21:50,640
there was no way out of that it would

1623
01:21:55,930 --> 01:21:53,820
take only uh quite I mean a few

1624
01:22:06,010 --> 01:21:55,940
centuries three four centuries before

1625
01:22:13,430 --> 01:22:08,570
telescope to the sky

1626
01:22:17,390 --> 01:22:13,440
uh so 1609 was much later and and as you

1627
01:22:19,490 --> 01:22:17,400
know as soon as Galileo did look at the

1628
01:22:22,370 --> 01:22:19,500
sky not by naked eye but with some

1629
01:22:25,669 --> 01:22:22,380
instrument he he made uh incredible

1630
01:22:29,570 --> 01:22:25,679
discoveries like the mountains of the

1631
01:22:32,649 --> 01:22:29,580
moon like the satellites of Jupiter the

1632
01:22:36,229 --> 01:22:32,659
faces of Venus

1633
01:22:39,530 --> 01:22:36,239
and so on and they were published in the

1634
01:22:41,630 --> 01:22:39,540
in the cedaris lunches in uh just a year

1635
01:22:46,669 --> 01:22:41,640
later in 1610

1636
01:22:49,070 --> 01:22:46,679
uh but that was long after Dante

1637
01:22:50,990 --> 01:22:49,080
uh spirilla would you mind stopping your

1638
01:22:54,110 --> 01:22:51,000
screen share real quick so that the

1639
01:22:56,810 --> 01:22:54,120
audience can see all of us yes

1640
01:23:06,350 --> 01:22:56,820
thank you okay

1641
01:23:12,229 --> 01:23:08,390
so do you have uh another question there

1642
01:23:14,209 --> 01:23:12,239
there Grant or I can try and mine

1643
01:23:15,770 --> 01:23:14,219
through my things that I've got I've got

1644
01:23:18,649 --> 01:23:15,780
so many notes

1645
01:23:22,189 --> 01:23:18,659
um in particular the

1646
01:23:23,750 --> 01:23:22,199
the relevance of the Aristotelian view

1647
01:23:29,209 --> 01:23:23,760
of the

1648
01:23:32,149 --> 01:23:29,219
and such and the sort of parallels to

1649
01:23:35,330 --> 01:23:32,159
the um the nine spheres and then the

1650
01:23:38,090 --> 01:23:35,340
nine other spheres that um uh you

1651
01:23:40,370 --> 01:23:38,100
mentioned for for Dante's Universe

1652
01:23:43,130 --> 01:23:40,380
um how much I mean what sort correlation

1653
01:23:47,270 --> 01:23:43,140
is there between the Aristotelian view

1654
01:23:49,850 --> 01:23:47,280
um and and Dante's Dante's presentation

1655
01:23:54,410 --> 01:23:49,860
well

1656
01:23:59,209 --> 01:23:54,420
done it definitely had a very uh big

1657
01:24:01,490 --> 01:23:59,219
admiration for Aristotle but mostly as a

1658
01:24:04,030 --> 01:24:01,500
philosopher

1659
01:24:10,610 --> 01:24:06,590
also in a sense the view of the universe

1660
01:24:13,330 --> 01:24:10,620
but they I thought they did not have his

1661
01:24:18,610 --> 01:24:13,340
own view of the universe he was

1662
01:24:21,470 --> 01:24:18,620
helped by astronomers I mean by parkos

1663
01:24:23,689 --> 01:24:21,480
so these were the astronomers who

1664
01:24:26,689 --> 01:24:23,699
actually had built

1665
01:24:30,229 --> 01:24:26,699
the view of the universe at the Dante's

1666
01:24:33,050 --> 01:24:30,239
time is totally uh did not do that but

1667
01:24:37,250 --> 01:24:33,060
still uh Dante was a great admirer

1668
01:24:38,870 --> 01:24:37,260
because of his philosophy and his logic

1669
01:24:41,870 --> 01:24:38,880
and yeah

1670
01:24:44,330 --> 01:24:41,880
yeah and you uh were spot on when you

1671
01:24:46,130 --> 01:24:44,340
mentioned how um back in those days

1672
01:24:47,930 --> 01:24:46,140
being a philosopher meant you could

1673
01:24:49,610 --> 01:24:47,940
study all difference of what all

1674
01:24:52,669 --> 01:24:49,620
different types of Sciences that we

1675
01:24:54,050 --> 01:24:52,679
consider totally disparate today and I

1676
01:24:56,209 --> 01:24:54,060
absolutely agree with you I'm totally

1677
01:24:59,209 --> 01:24:56,219
jealous of uh folks who lived in that

1678
01:25:02,870 --> 01:24:59,219
time for at least that aspect you know

1679
01:25:04,310 --> 01:25:02,880
being able to uh be an expert in many

1680
01:25:07,850 --> 01:25:04,320
different Sciences which is totally

1681
01:25:11,090 --> 01:25:07,860
impossible today it is it is in fact uh

1682
01:25:15,250 --> 01:25:11,100
let me tell you a little story about

1683
01:25:19,010 --> 01:25:15,260
about this you know in in uh in in

1684
01:25:21,229 --> 01:25:19,020
2021 was the 700th anniversary of

1685
01:25:23,510 --> 01:25:21,239
Dante's death so there were big

1686
01:25:26,689 --> 01:25:23,520
celebrations in Italy and also elsewhere

1687
01:25:29,450 --> 01:25:26,699
in the world and because of that I gave

1688
01:25:31,729 --> 01:25:29,460
several conferences about Dante's

1689
01:25:35,330 --> 01:25:31,739
cosmography

1690
01:25:37,970 --> 01:25:35,340
um any in one of them uh after I'd

1691
01:25:41,330 --> 01:25:37,980
finished my talk uh somebody came to me

1692
01:25:44,990 --> 01:25:41,340
and they said well I am a teacher in

1693
01:25:47,390 --> 01:25:45,000
high school and I teach Dante you know

1694
01:25:51,590 --> 01:25:47,400
in Italy uh Dante study in high school

1695
01:25:54,410 --> 01:25:51,600
in the last three years and in each one

1696
01:25:58,310 --> 01:25:54,420
of the of the last two years one reads

1697
01:26:02,030 --> 01:25:58,320
at high school Inferno purgatory and

1698
01:26:03,229 --> 01:26:02,040
Paradise and so I I read this all to my

1699
01:26:07,850 --> 01:26:03,239
students

1700
01:26:11,030 --> 01:26:07,860
but when I get to the second Kanto of

1701
01:26:12,709 --> 01:26:11,040
paradise I skip it because I don't know

1702
01:26:14,870 --> 01:26:12,719
how to explain it

1703
01:26:17,209 --> 01:26:14,880
you know the second kind of paradise the

1704
01:26:19,550 --> 01:26:17,219
one I thought uh talked about it's about

1705
01:26:24,110 --> 01:26:19,560
the the moon spots and of course

1706
01:26:25,250 --> 01:26:24,120
somebody who does not know about the

1707
01:26:26,930 --> 01:26:25,260
um

1708
01:26:29,330 --> 01:26:26,940
the fact that the surface brightness

1709
01:26:33,470 --> 01:26:29,340
does not depend on distance

1710
01:26:36,790 --> 01:26:33,480
how can he explain the Canto so he told

1711
01:26:40,669 --> 01:26:36,800
me I can and actually this is

1712
01:26:43,250 --> 01:26:40,679
this is reinforces my idea that you you

1713
01:26:44,570 --> 01:26:43,260
cannot just listen to one person if you

1714
01:26:48,050 --> 01:26:44,580
want to understand that you have to

1715
01:26:52,669 --> 01:26:51,530
uh yes so it sounds like many faceted uh

1716
01:26:54,290 --> 01:26:52,679
presentation

1717
01:26:56,750 --> 01:26:54,300
um I think I saw another question in the

1718
01:26:58,910 --> 01:26:56,760
chat there Grant can do

1719
01:27:03,229 --> 01:26:58,920
yeah absolutely

1720
01:27:05,390 --> 01:27:03,239
um so uh does Dante try to tell us how

1721
01:27:08,450 --> 01:27:05,400
the Earth shifted uh this person makes

1722
01:27:11,570 --> 01:27:08,460
reference to the circles and stones for

1723
01:27:14,689 --> 01:27:11,580
calculating positions after the 13 000

1724
01:27:19,970 --> 01:27:17,990
oh I I'm sorry I do not understand this

1725
01:27:21,470 --> 01:27:19,980
question yeah I wasn't sure what this

1726
01:27:23,510 --> 01:27:21,480
question was was referring to either

1727
01:27:27,169 --> 01:27:23,520
with the 13 000 year disaster what that

1728
01:27:29,090 --> 01:27:27,179
meant okay 13 000 years is just half of

1729
01:27:32,030 --> 01:27:29,100
the period of the procession of the

1730
01:27:35,090 --> 01:27:32,040
equinoxes but

1731
01:27:36,590 --> 01:27:35,100
this is the only team I can say

1732
01:27:39,530 --> 01:27:36,600
it's okay

1733
01:27:43,610 --> 01:27:39,540
um did Dante use Virgil and Homer to

1734
01:27:49,810 --> 01:27:46,010
ah Ah that's an interesting question

1735
01:27:52,250 --> 01:27:49,820
well definitely

1736
01:27:54,290 --> 01:27:52,260
yes but there are interesting things to

1737
01:27:59,390 --> 01:27:54,300
say about this

1738
01:28:02,830 --> 01:27:59,400
uh of course Virgil was very much loved

1739
01:28:05,930 --> 01:28:02,840
by Dante and admired by Dante and and

1740
01:28:09,050 --> 01:28:05,940
this is demonstrated definitely by the

1741
01:28:12,410 --> 01:28:09,060
fact that virgin is Dante's leader

1742
01:28:14,930 --> 01:28:12,420
through our hell and Paradise you know

1743
01:28:17,750 --> 01:28:14,940
this is very it means that he was very

1744
01:28:21,770 --> 01:28:17,760
important for Dante

1745
01:28:25,070 --> 01:28:21,780
but about Homer it's it's different well

1746
01:28:28,729 --> 01:28:25,080
first of all Dante could not read Greeks

1747
01:28:33,169 --> 01:28:28,739
Greek ancient Greek he could not read it

1748
01:28:35,149 --> 01:28:33,179
so he had uh heard about

1749
01:28:39,169 --> 01:28:35,159
Uma definitely

1750
01:28:43,490 --> 01:28:39,179
but probably only through translations

1751
01:28:46,370 --> 01:28:43,500
in in in in Latin

1752
01:28:49,010 --> 01:28:46,380
um and in fact it's it's very

1753
01:28:52,850 --> 01:28:49,020
interesting that when he talks about

1754
01:28:59,390 --> 01:28:52,860
Ulysses which of course the the the main

1755
01:29:04,729 --> 01:29:02,870
um well he does not refer to what

1756
01:29:06,490 --> 01:29:04,739
almost wrote

1757
01:29:09,970 --> 01:29:06,500
but he he

1758
01:29:13,330 --> 01:29:09,980
tells a new story a completely new story

1759
01:29:16,490 --> 01:29:13,340
uh which is the story of the last

1760
01:29:20,270 --> 01:29:16,500
journey of Lisa's

1761
01:29:22,850 --> 01:29:20,280
uh trying to discover the the the Earth

1762
01:29:25,070 --> 01:29:22,860
outside the Gibraltar outside the limits

1763
01:29:30,910 --> 01:29:25,080
made by Hercules

1764
01:29:36,110 --> 01:29:34,370
it's hard to actually I've read

1765
01:29:40,209 --> 01:29:36,120
something about this people do not

1766
01:29:43,610 --> 01:29:40,219
really know how much Dante knew about

1767
01:29:50,110 --> 01:29:43,620
homeless Works he probably had heard

1768
01:29:55,189 --> 01:29:53,750
all right so we have another good one

1769
01:29:56,629 --> 01:29:55,199
um this will be the last one because

1770
01:29:59,629 --> 01:29:56,639
we're getting to time

1771
01:30:03,229 --> 01:30:00,890
okay

1772
01:30:04,729 --> 01:30:03,239
um did Dante travel to other regions or

1773
01:30:08,870 --> 01:30:04,739
did he spend most of his time in

1774
01:30:14,229 --> 01:30:08,880
Florence no no no no no no no Dante

1775
01:30:15,790 --> 01:30:14,239
um was exiled from Florence by on in

1776
01:30:21,550 --> 01:30:15,800
1301

1777
01:30:24,530 --> 01:30:21,560
and when he was uh 35 years old

1778
01:30:28,189 --> 01:30:24,540
uh and it's not by chance that actually

1779
01:30:31,689 --> 01:30:28,199
the the the divine's comedy trip is is

1780
01:30:34,910 --> 01:30:31,699
imagined to be right on that year 1301.

1781
01:30:36,590 --> 01:30:34,920
uh but then since he was exiled he could

1782
01:30:40,610 --> 01:30:36,600
not go back to Florence although he

1783
01:30:44,030 --> 01:30:40,620
wanted to he so he traveled around Italy

1784
01:30:48,290 --> 01:30:44,040
in in many different places

1785
01:30:52,490 --> 01:30:48,300
um he spent he spent a lot of time uh in

1786
01:30:55,970 --> 01:30:52,500
Verona uh Verona is is a town in in the

1787
01:31:00,050 --> 01:30:55,980
northeast of Italy and and that town was

1788
01:31:01,610 --> 01:31:00,060
ruled by a family called De La Scala and

1789
01:31:03,950 --> 01:31:01,620
he spent quite a lot of time there

1790
01:31:09,590 --> 01:31:03,960
actually

1791
01:31:11,390 --> 01:31:09,600
um his son Pietro uh also lived there

1792
01:31:15,830 --> 01:31:11,400
and his son

1793
01:31:21,830 --> 01:31:15,840
in in 1353 actually the 28th of April of

1794
01:31:23,930 --> 01:31:21,840
1353 bought a land near Verona in in in

1795
01:31:27,470 --> 01:31:23,940
a region where they make good wine

1796
01:31:30,830 --> 01:31:27,480
valpolice Verona and that piece of land

1797
01:31:33,709 --> 01:31:30,840
is still owned by my family

1798
01:31:36,790 --> 01:31:33,719
uh then Dante

1799
01:31:40,850 --> 01:31:36,800
lived also quite a few years in Ravena

1800
01:31:43,010 --> 01:31:40,860
you know in the on near near the

1801
01:31:47,270 --> 01:31:43,020
Atlantic coast where he actually died

1802
01:31:52,850 --> 01:31:49,790
so he traveled he traveled around Italy

1803
01:31:56,270 --> 01:31:52,860
quite a lot but although if you go

1804
01:31:58,550 --> 01:31:56,280
around Italy in in many towns you see

1805
01:32:00,169 --> 01:31:58,560
Stones which says yeah Dante has been

1806
01:32:05,030 --> 01:32:00,179
here yeah

1807
01:32:08,870 --> 01:32:05,040
well uh be careful because actually the

1808
01:32:12,310 --> 01:32:08,880
the presence of Dante is documented by

1809
01:32:16,070 --> 01:32:12,320
documents of the time only in Florence

1810
01:32:18,950 --> 01:32:16,080
Verona Ravina and there is another town

1811
01:32:22,970 --> 01:32:18,960
which is called sarzana sadhana is a

1812
01:32:26,050 --> 01:32:22,980
town uh in in the north of Tuscany

1813
01:32:28,850 --> 01:32:26,060
um near liguria near near La special

1814
01:32:33,530 --> 01:32:28,860
Dante has been there because there is a

1815
01:32:35,510 --> 01:32:33,540
document made by a lawyer uh document of

1816
01:32:38,209 --> 01:32:35,520
the time which says that Dante was there

1817
01:32:39,890 --> 01:32:38,219
and he actually had testified for some

1818
01:32:42,770 --> 01:32:39,900
reasons there

1819
01:32:44,050 --> 01:32:42,780
so be careful the people tell that has

1820
01:32:49,250 --> 01:32:44,060
been here then there's been here yeah

1821
01:32:53,090 --> 01:32:51,169
yeah sort of in the U.S we have the

1822
01:32:55,070 --> 01:32:53,100
George Washington slept here type thing

1823
01:32:56,930 --> 01:32:55,080
uh how are people always claiming that

1824
01:33:00,169 --> 01:32:56,940
you know famous people had come through

1825
01:33:02,810 --> 01:33:00,179
there all right well thank you so much

1826
01:33:05,209 --> 01:33:02,820
um this really uh transforms the story

1827
01:33:07,430 --> 01:33:05,219
or gives a totally new aspect to the

1828
01:33:09,830 --> 01:33:07,440
story uh for this

1829
01:33:13,070 --> 01:33:09,840
um I will say that next month is

1830
01:33:16,310 --> 01:33:13,080
November 1st uh black holes how do we

1831
01:33:18,770 --> 01:33:16,320
see that which gives off no light we

1832
01:33:21,229 --> 01:33:18,780
hope to see all of you there uh thank

1833
01:33:23,629 --> 01:33:21,239
you very much again sparello and we will