00:00:06.667,00:00:12.467 !!musiC@!!!musiC@! 00:00:14.567,00:00:24.567 !!musiC@!!!musiC@! 00:00:24.567,00:00:34.534 !!musiC@!!!musiC@! 00:00:34.534,00:00:44.534 !!musiC@!!!musiC@! 00:00:44.534,00:00:54.501 !!musiC@!!!musiC@! 00:00:54.501,00:01:04.567 !!musiC@!!!musiC@! 00:01:04.567,00:01:09.367 -In 1923, Hermann Oberth, a German scientist, 00:01:09.367,00:01:10.701 in a book entitled 00:01:10.701,00:01:13.400 "The Rocket into Interplanetary Space," 00:01:13.400,00:01:15.667 put forward a dream -- 00:01:15.667,00:01:17.167 if we could look at the heavens 00:01:17.167,00:01:20.133 with an astronomical telescope in orbit, 00:01:20.133,00:01:22.834 unhindered by the shielding sea of atmosphere 00:01:22.834,00:01:24.501 that blankets the Earth, 00:01:24.501,00:01:26.734 think of the discoveries we would make, 00:01:26.734,00:01:31.834 the clear vision of the universe we would have in quiet space. 00:01:31.834,00:01:39.901 !!musiC@!!!musiC@! 00:01:39.901,00:01:48.000 !!musiC@!!!musiC@! 00:01:48.000,00:01:56.067 !!musiC@!!!musiC@! 00:01:56.067,00:02:04.200 !!musiC@!!!musiC@! 00:02:08.667,00:02:12.267 The telescope -- an instrument for collecting more light 00:02:12.267,00:02:15.033 than would normally enter the human eye. 00:02:15.033,00:02:20.667 For over 300 years, light, optics and the human imagination 00:02:20.667,00:02:23.501 have sculptured our perception of the universe. 00:02:27.067,00:02:30.767 Today, large telescopes such as those at Palomar Mountain 00:02:30.767,00:02:32.100 and Kitt Peak 00:02:32.100,00:02:34.133 carry out detailed investigations 00:02:34.133,00:02:35.934 of very faint objects 00:02:35.934,00:02:37.701 at the limits of perception. 00:02:41.767,00:02:45.767 The naked eye has been replaced by spectroscopes, 00:02:45.767,00:02:49.834 photographic plates, computers, 00:02:49.834,00:02:52.033 yet a fundamental challenge, 00:02:52.033,00:02:56.534 a link between past and present, remains ever constant. 00:02:59.100,00:03:01.567 The quest for more light -- 00:03:01.567,00:03:04.734 to see fainter and more distant objects, 00:03:04.734,00:03:08.968 to construct better light collectors. 00:03:08.968,00:03:14.334 -This is a photograph of the galaxy in Messier 33, 00:03:14.334,00:03:17.934 a nearby galaxy, a rather common type, 00:03:17.934,00:03:22.400 and quite illustrative of the type of image 00:03:22.400,00:03:24.634 that we obtain with telescopes 00:03:24.634,00:03:28.767 that are based on the surface of the Earth. 00:03:28.767,00:03:31.334 This type of information, 00:03:31.334,00:03:34.100 together with spectra 00:03:34.100,00:03:39.100 like the plate that I'm holding here, 00:03:39.100,00:03:43.367 form the largest part of the information obtained 00:03:43.367,00:03:47.000 and used by ground-based astronomers. 00:03:47.000,00:03:52.467 It's quite good, but nowhere as good as it might be. 00:03:52.467,00:03:56.534 Astronomers themselves and many in the lay public 00:03:56.534,00:04:01.267 don't appreciate at times the enormous distances 00:04:01.267,00:04:04.000 that they're dealing with. 00:04:04.000,00:04:08.000 When we look at the photograph of a cluster of galaxies 00:04:08.000,00:04:10.067 like this, 00:04:10.067,00:04:15.200 it's hard to appreciate that these images 00:04:15.200,00:04:18.868 that we obtain now are from galaxies 00:04:18.868,00:04:23.367 that are probably a billion light-years away. 00:04:23.367,00:04:25.234 With space telescope, 00:04:25.234,00:04:29.100 we'll be able to look to much greater distances 00:04:29.100,00:04:33.734 and therefore much further back into time, 00:04:33.734,00:04:40.200 in fact, much closer to the creation of the universe itself. 00:04:40.200,00:04:46.067 In order to understand how the Space Telescope works, 00:04:46.067,00:04:49.167 we really need to understand how the astronomer 00:04:49.167,00:04:52.834 and the astrophysicist work with light. 00:04:57.234,00:05:00.200 -Almost all the information we have about the universe 00:05:00.200,00:05:03.434 reaches us in the form of electromagnetic radiation, 00:05:03.434,00:05:08.000 which objects either radiate, absorb or reflect. 00:05:08.000,00:05:10.133 The spectrum disperses this radiation 00:05:10.133,00:05:12.000 into its separate colors -- 00:05:12.000,00:05:15.033 visible light, infrared radiation, 00:05:15.033,00:05:19.934 radio waves at one end to x-rays and gamma rays at the other. 00:05:23.334,00:05:24.701 Now, each element in nature 00:05:24.701,00:05:27.567 has a characteristic spectral signature, 00:05:27.567,00:05:30.334 a fingerprint of light, if you will. 00:05:30.334,00:05:32.667 Because common Earthly elements have been found 00:05:32.667,00:05:34.634 in the Sun and stars, 00:05:34.634,00:05:36.901 we can determine through a star's own unique 00:05:36.901,00:05:40.033 stellar spectrum the speed of an object, 00:05:40.033,00:05:44.734 its temperature, density, chemical composition. 00:05:44.734,00:05:48.300 Each band of light becomes a window into the universe 00:05:48.300,00:05:50.567 with a unique view. 00:05:50.567,00:05:56.167 !!musiC@!!!musiC@! 00:05:56.167,00:05:58.868 But many wavelengths are permanently inaccessible 00:05:58.868,00:06:02.234 to astronomers using earthbound telescopes 00:06:02.234,00:06:03.934 due to the Earth's atmosphere 00:06:03.934,00:06:05.234 which, enshielding us 00:06:05.234,00:06:08.534 from most of the biologically harmful radiations, 00:06:08.534,00:06:12.667 allows only visible light and varying amounts of ultraviolet, 00:06:12.667,00:06:15.834 infrared and radio to reach the ground. 00:06:18.300,00:06:21.334 We are given a very incomplete picture of the universe 00:06:21.334,00:06:23.167 in these wavelengths. 00:06:23.167,00:06:27.901 Our stellar fingerprint is difficult to analyze. 00:06:27.901,00:06:30.601 The atmosphere also frustrates ground-based 00:06:30.601,00:06:32.834 optical observations. 00:06:32.834,00:06:36.634 100 miles deep, it is filled with dust particles, 00:06:36.634,00:06:40.300 water vapor and other obscuring materials. 00:06:40.300,00:06:43.734 Constantly shifting layers of air of different densities 00:06:43.734,00:06:47.501 bend light back and forth. 00:06:47.501,00:06:50.767 Atmospheric turbulence imposes a fundamental limitation 00:06:50.767,00:06:52.100 on the telescope's ability 00:06:52.100,00:06:56.634 to see clearly two objects close together in the sky. 00:06:56.634,00:06:58.701 At times of bad seeing, 00:06:58.701,00:07:03.434 stellar images waver like candle flames in a gentle breeze. 00:07:07.100,00:07:08.400 The Space Telescope 00:07:08.400,00:07:11.501 will be out where the images are completely quiet, 00:07:11.501,00:07:14.501 where the full spatial and wavelength resolution 00:07:14.501,00:07:17.567 powers of the telescope can be used. 00:07:17.567,00:07:19.701 It will peer far into the ultraviolet 00:07:19.701,00:07:22.133 and infrared regions of the spectrum. 00:07:24.667,00:07:28.067 A galaxy, seen through the Earth's atmosphere 00:07:28.067,00:07:32.334 as a big, shimmering fuzz ball in space, 00:07:32.334,00:07:34.901 will be brought into sharp, clear 00:07:34.901,00:07:38.334 and steady view for study and analysis. 00:07:38.334,00:07:42.000 We will see it 10 times clearer than we see it now. 00:07:42.000,00:07:45.234 We will see 50 times further into the universe 00:07:45.234,00:07:48.934 than the best ground-based telescopes can see -- 00:07:48.934,00:07:52.434 all this from a telescope no different in principal 00:07:52.434,00:07:57.667 than the reflecting telescope of Newton and his descendants. 00:07:57.667,00:07:59.267 -Every optical telescope 00:07:59.267,00:08:02.067 operates in essentially the same manner. 00:08:02.067,00:08:05.267 It gathers a part of the light produced by or reflected 00:08:05.267,00:08:06.601 from an object, 00:08:06.601,00:08:09.434 concentrates this light in a single area, 00:08:09.434,00:08:10.868 the focal plane, 00:08:10.868,00:08:13.901 and then magnifies the image formed there. 00:08:13.901,00:08:18.868 !!musiC@!!!musiC@! 00:08:18.868,00:08:25.601 -So in space, as on Earth, we must begin with a mirror, 00:08:25.601,00:08:27.701 in this case, polished to within one 00:08:27.701,00:08:31.434 half a millionth of an inch in accuracy. 00:08:31.434,00:08:33.467 As light enters from space, 00:08:33.467,00:08:35.200 something must catch the reflection 00:08:35.200,00:08:37.267 of our primary mirror. 00:08:37.267,00:08:40.434 A secondary mirror is set into place. 00:08:40.434,00:08:43.000 An image must now be fed into a variety 00:08:43.000,00:08:45.467 of auxiliary instruments, 00:08:45.467,00:08:49.367 so we provide a package of five major scientific instruments 00:08:49.367,00:08:53.868 which will convert telescope images into useful data. 00:08:53.868,00:08:56.601 The scientific instruments and optical assembly 00:08:56.601,00:08:59.067 must then be encased in a shell, 00:08:59.067,00:09:02.634 which protects them from dangers in the space environment 00:09:02.634,00:09:07.234 such as stray light or micrometeoroids. 00:09:07.234,00:09:11.300 To power our telescope, we tune to the sun for energy 00:09:11.300,00:09:14.000 and attach solar array panels. 00:09:14.000,00:09:15.400 In the Earth's shadow, 00:09:15.400,00:09:19.767 we will power our telescope by batteries. 00:09:19.767,00:09:22.634 Finally, we must have a means of communicating 00:09:22.634,00:09:24.133 with our telescope, 00:09:24.133,00:09:27.667 so we obtain two high-gain antennas. 00:09:27.667,00:09:30.567 Data which these antennas beam back to Earth 00:09:30.567,00:09:32.434 will be converted to pictures. 00:09:32.434,00:09:37.100 !!musiC@!!!musiC@! 00:09:39.133,00:09:42.834 -200-inch telescope here at Mount Palomar in California 00:09:42.834,00:09:46.534 is only about twice as big as the Space Telescope will be, 00:09:46.534,00:09:48.234 yet it's very much more massive 00:09:48.234,00:09:51.300 because of course it has to work in the Earth's gravity. 00:09:51.300,00:09:52.734 Our own telescopes, 00:09:52.734,00:09:54.434 including this one and the Space Telescope, 00:09:54.434,00:09:56.434 are essentially the same. 00:09:56.434,00:09:58.367 They gather light so that we can analyze it 00:09:58.367,00:10:00.133 with various instruments. 00:10:00.133,00:10:03.067 The Space Telescope will have five such instruments. 00:10:03.067,00:10:04.868 There will be two wide-field cameras, 00:10:04.868,00:10:08.968 which take pictures of the sky, one over a wide region 00:10:08.968,00:10:11.801 and another over a smaller region. 00:10:11.801,00:10:16.501 The smaller-region camera will have much higher resolution 00:10:16.501,00:10:18.000 than the other. 00:10:18.000,00:10:19.501 There will also be two spectrographs 00:10:19.501,00:10:21.167 aboard the Space Telescope. 00:10:21.167,00:10:23.667 One will be used on fairly bright objects 00:10:23.667,00:10:26.667 and take the highest-resolution spectra. 00:10:26.667,00:10:30.467 The other will be used for quite faint objects 00:10:30.467,00:10:33.934 such as galaxies and far-away quasi-stellar sources. 00:10:33.934,00:10:36.501 There will also be on the Space Telescope an instrument 00:10:36.501,00:10:39.400 that utilizes the fine guidance system of the telescope. 00:10:39.400,00:10:41.367 This is the system that keeps the telescope 00:10:41.367,00:10:45.734 pointed quite accurately at the stars during an exposure. 00:10:45.734,00:10:48.434 This instrument will allow us to measure the distance 00:10:48.434,00:10:51.267 between stars quite accurately on the sky 00:10:51.267,00:10:55.467 and also their motions over a short period of time. 00:10:57.801,00:11:01.767 -The Space Telescope, due to be launched in the 1980s, 00:11:01.767,00:11:05.501 will be hoisted into orbit some 500 miles above the Earth 00:11:05.501,00:11:07.634 by the space shuttle. 00:11:07.634,00:11:09.968 Fitting into the shuttle's cargo bay, 00:11:09.968,00:11:13.167 the telescope will be latched to a tilting mechanism 00:11:13.167,00:11:17.334 and rotated into a 90-degree position for checkout. 00:11:17.334,00:11:20.167 It will then be placed in a vertical angle, 00:11:20.167,00:11:24.667 released and its power and communication systems deployed. 00:11:28.901,00:11:31.701 The periodic revisit of the shuttle will allow 00:11:31.701,00:11:33.567 for the replacement of components 00:11:33.567,00:11:35.634 and routine maintenance. 00:11:35.634,00:11:38.834 Every 5 years, the telescope will be returned to Earth 00:11:38.834,00:11:41.467 for major ground refurbishment. 00:11:41.467,00:11:44.934 This ability to service the telescope through human care 00:11:44.934,00:11:48.267 will extend its life-span up to 20 years. 00:11:50.367,00:11:53.200 -It will orbit above our murky atmosphere 00:11:53.200,00:11:55.667 and obtain images of objects 00:11:55.667,00:11:58.501 that are incredible distances away, 00:11:58.501,00:12:03.300 perhaps a galaxy's 14 billion light-years' distance, 00:12:03.300,00:12:08.601 so far away that when the light first set out towards us, 00:12:08.601,00:12:13.067 there was no Earth, no Sun, no Milky Way Galaxy. 00:12:13.067,00:12:16.634 We will be probing the time of the earliest history 00:12:16.634,00:12:17.701 of the universe. 00:12:17.701,00:12:20.367 The Space Telescope is, in a way, 00:12:20.367,00:12:23.200 a little like Galileo's first telescope. 00:12:23.200,00:12:25.834 Wherever Galileo pointed his telescope, 00:12:25.834,00:12:27.934 he made major new discoveries. 00:12:27.934,00:12:30.267 Look at the moon. You find mountains and craters. 00:12:30.267,00:12:32.133 Look at Saturn. You find rings. 00:12:32.133,00:12:33.434 Look at the Milky Way. 00:12:33.434,00:12:38.300 You find it is littered and composed of stars. 00:12:38.300,00:12:39.467 Every one of these discoveries, 00:12:39.467,00:12:42.000 things that people had not known before. 00:12:42.000,00:12:43.567 I think it's going to be very similar 00:12:43.567,00:12:45.868 with the Space Telescope. 00:12:45.868,00:12:50.400 It will illuminate celestial objects that we know about. 00:12:50.400,00:12:54.501 It will discover celestial objects never before guessed. 00:12:54.501,00:12:59.100 It will provide insights into the most important questions 00:12:59.100,00:13:01.400 such as stellar evolution, 00:13:01.400,00:13:06.601 such as the search for planets going in and out of the stars 00:13:06.601,00:13:11.033 and the grandest cosmological questions of the origin, 00:13:11.033,00:13:13.033 nature and fate of the universe. 00:13:13.033,00:13:18.234 The Space Telescope is a kind of grand intellectual adventure 00:13:18.234,00:13:19.434 for all of us, 00:13:19.434,00:13:24.467 which will cast light not just on the cosmos 00:13:24.467,00:13:26.601 but also on ourselves. 00:13:28.968,00:13:33.033 -It's impossible to predict what Space Telescope will bring 00:13:33.033,00:13:35.968 in terms of its results, 00:13:35.968,00:13:39.868 but we do know the results will be exciting. 00:13:39.868,00:13:42.334 When the first radio telescopes were built, 00:13:42.334,00:13:46.701 we did not know that we would find quasars and pulsars, 00:13:46.701,00:13:49.601 or when the first x-ray telescopes were built, 00:13:49.601,00:13:54.767 we did not know that we would discover x-ray stars. 00:13:54.767,00:13:58.000 With Space Telescope, we will find many new things. 00:13:58.000,00:14:00.167 We'll find exciting things. 00:14:03.667,00:14:07.467 -Stretching the mind of humankind to the very beginning 00:14:07.467,00:14:10.567 and end of space and time, 00:14:10.567,00:14:12.400 the Space Telescope may tell us 00:14:12.400,00:14:16.634 at last whether the universe will expand forever 00:14:16.634,00:14:19.000 or whether that expansion is slowing. 00:14:19.000,00:14:24.467 !!musiC@!!!musiC@! 00:14:24.467,00:14:29.934 !!musiC@!!!musiC@! 00:14:29.934,00:14:32.601 It may help us learn more about the violent events 00:14:32.601,00:14:35.000 of the universe -- 00:14:35.000,00:14:37.000 pulsars... 00:14:37.000,00:14:39.667 quasars... 00:14:39.667,00:14:41.467 the gravitational implosions 00:14:41.467,00:14:43.434 that produce black holes. 00:14:43.434,00:14:52.601 !!musiC@!!!musiC@! 00:14:52.601,00:14:55.534 It may also tell us how the universe began 00:14:55.534,00:14:57.534 and how it will end. 00:15:02.467,00:15:07.400 But ultimately, as is the case with all voyages of discovery, 00:15:07.400,00:15:11.267 its greatest contribution will be the unexpected breakthrough 00:15:11.267,00:15:14.133 that brings completely new knowledge.