Full transcript
0:00if we go back to our slide from last
0:03week and look at the electromagnetic
0:04spectrum and how it interacts with our
0:06atmosphere how its absorbed by our
0:08atmosphere a clearer picture starts to
0:10emerge we've got the visible part
0:12remember that goes all the way down and
0:14we can see it on earth whereas the radio
0:16as well we have these optical and radio
0:18windows so we can actually do visible
0:22astronomy and radio astronomy from the
0:24surface of Earth and we said we can do
0:27some infrared as well it's pretty
0:29difficult but some of it gets blocked
0:32but not all Vince it can make it pretty
0:35far down in the atmosphere and so what
0:38they started to try to do early on was
0:41actually try and get higher up in our
0:43atmosphere they did things like trying
0:45to use balloons and actually one of the
0:47early attempts was actually a plane they
0:50put an infrared telescope in a plane and
0:54try to detect infrared rays actually do
0:58infrared astronomy from a plane so it
1:01was kind of a neat way of doing it
1:03and again we're getting a buffs on the
1:05atmosphere some of the interference and
1:08also hopefully that'll help cool things
1:11down a bit because we're getting higher
1:12up in the atmosphere it's gonna be
1:13colder but even better is if we can put
1:16it in space space is incredibly cold so
1:20that idea that we have to make a
1:22telescope and infrared one down to about
1:25a couple Kelvin that's a lot easier in
1:28space because we're not getting the
1:30heating effects we just have to make
1:32sure the actual operating material of
1:36the telescope itself doesn't get heated
1:37so putting it in space is the ideal
1:41solution of course this isn't cheap just
1:45have rockets to launch it into space so
1:47this isn't always the most practical
1:49option and that's why we still do a lot
1:52of observations from Earth because it is
1:55very expensive but it is worth it
1:58especially when we started looking those
1:59parts the spectrum like infrared that
2:01are hard to see from Earth we can get
2:03these spectacular images and study these
2:05objects that are difficult to study
2:06otherwise but it's also nice to try and
2:12do
2:13and visible from space as well again
2:16remember we get that twinkling of the
2:18stars because of the atmosphere and we
2:20try to increase our resolution well in
2:22space we don't have to worry about the
2:24atmosphere limiting our resolution
2:26because there's no atmosphere so putting
2:29a visible telescope in space allows us
2:31to get images of amazing quality only
2:34limited by the size of the telescope
2:36itself and one of the most famous one of
2:39the most significant missions was the
2:41hubble space telescope
2:43this actually was designed to get
2:45visible infrared and ultraviolet
2:47radiation haven't really alluded to this
2:50before but really ultraviolet could also
2:52be used or used the same kind of mirrors
2:55we use for visible so the same basic
2:57setup we use for visible really covers
2:59infrared and ultraviolet again really
3:01the CCDs the detector changes but the
3:04basic setup remains the same for all
3:06three of those now Hubble telescope
3:10again was an incredibly important
3:14mission it was meant to change the way
3:17we used see the universe see objects
3:20we'd never witnessed before in details
3:22we never could
3:23but when Hubble was first launched and
3:26we started to make our images there is a
3:29huge problem
3:30they were blurry it turned out the main
3:35mirror was actually had a design flaw
3:39it was just slightly out of shape by
3:43about one fiftieth the width of a human
3:46hair think about that and if you've got
3:49a hair lying around that's following on
3:50your shoulder look at your hair and
3:52think one-fiftieth the width of that
3:54that's how little misshapen this mirror
3:58was but it meant the images were blurry
4:03they weren't what we had expected this
4:05was a huge blow in terms of what we were
4:08hoping to get from the Hubble Space
4:09Telescope so what they actually ended up
4:12having to do is send some astronauts up
4:14there and basically in essence give it
4:17glasses give it corrective optics to try
4:21to account for this which did actually
4:24work and now the Hubble Space
4:26Telescope's been providing amazing
4:28images ever since since about 1993 it
4:33was fixed and it has been changing our
4:37way of looking at the universe
4:38identifying incredible images Deep Field
4:41images of tons of different galaxies I
4:43mean look at this image all these weird
4:46cool shaped galaxies and it's again
4:51originally was designed poorly
4:53apparently it was meant to save money
4:55they didn't do a full testing of the
4:58optical mirror before launching it oops
5:01but they did end up fixing it and we've
5:05gone spectacular images because again
5:07it's in space so there is no atmosphere
5:09to limit its resolution this mirror is
5:11not actually that big
5:13it's about 2.4 meters compared to some
5:17of the other ones we're talking about
5:18like the Keck that are 10 meters it's
5:20the only 2.4 but because it's in space
5:23you can get much better images it's not
5:25limited by that bad seeing caused by our
5:29atmosphere