1 00:00:18,626 --> 00:00:20,604 This is the Hubblecast. 2 00:00:20,605 --> 00:00:24,451 News and images from the NASA / ESA Hubble Space Telescope. 3 00:00:24,452 --> 00:00:28,019 Travelling through time and space with our host, Dr. J 4 00:00:28,020 --> 00:00:30,655 EPISODE 24: Beyond Earth a. k.a. Dr. Joe Liske. 5 00:00:30,656 --> 00:00:33,685 Welcome to this sixth special episode of the Hubblecast 6 00:00:33,686 --> 00:00:37,851 celebrating the International Year of Astronomy in 2009. 7 00:00:37,852 --> 00:00:40,881 In the fifth episode, we saw how some telescopes 8 00:00:40,882 --> 00:00:44,394 study parts of the Universe that we can't see with our eyes. 9 00:00:44,395 --> 00:00:47,233 This time we'll see how telescopes in space 10 00:00:47,234 --> 00:00:50,522 have revolutionised almost every field in astronomy. 11 00:00:52,348 --> 00:00:53,870 The Hubble Space Telescope. 12 00:00:53,871 --> 00:00:57,189 Is by far the most famous telescope in history. 13 00:00:57,190 --> 00:00:58,258 And for good reason. 14 00:00:58,259 --> 00:01:02,090 Hubble has revolutionised so many fields in astronomy. 15 00:01:02,091 --> 00:01:05,862 By modern standards, Hubble's mirror is actually quite small. 16 00:01:05,863 --> 00:01:08,719 It only measures about 2.4 metres across. 17 00:01:08,720 --> 00:01:12,294 But its location is literally out of this world. 18 00:01:12,295 --> 00:01:14,972 High above the blurring effects of the atmosphere, 19 00:01:14,973 --> 00:01:18,193 it has an exceptionally sharp view of the Universe. 20 00:01:18,194 --> 00:01:23,104 What's more, Hubble can see ultraviolet and near infrared light. 21 00:01:23,105 --> 00:01:25,912 This light just cannot be seen by ground based telescopes 22 00:01:25,913 --> 00:01:28,324 because it is blocked by the atmosphere. 23 00:01:29,645 --> 00:01:33,490 Cameras and spectrographs, some as big as a telephone booth, 24 00:01:33,491 --> 00:01:37,246 dissect and register the light from distant cosmic shores. 25 00:01:38,501 --> 00:01:43,141 Just like any ground based telescope, Hubble is upgraded from time to time. 26 00:01:43,142 --> 00:01:46,466 Spacewalking astronauts carry out servicing missions. 27 00:01:46,467 --> 00:01:50,069 Broken parts get refurbished and older instruments get replaced 28 00:01:50,070 --> 00:01:52,578 with newer and state-of-the-art technology. 29 00:01:53,509 --> 00:01:57,102 Hubble has become the powerhouse of observational astronomy. 30 00:01:57,103 --> 00:02:00,738 And it has transformed our understanding of the cosmos. 31 00:02:03,376 --> 00:02:09,094 With its keen eyesight, Hubble observed seasonal changes on Mars... 32 00:02:09,601 --> 00:02:12,975 a cometary impact on Jupiter... 33 00:02:14,130 --> 00:02:17,498 an edge-on view of Saturn's rings... 34 00:02:20,817 --> 00:02:24,265 and even the surface of tiny Pluto. 35 00:02:24,517 --> 00:02:27,751 It revealed the life cycle of stars, 36 00:02:27,752 --> 00:02:33,087 from their very birth and baby days in a nursery of dust-laden clouds of gas, 37 00:02:33,088 --> 00:02:36,522 all the way to their final farewell: 38 00:02:36,523 --> 00:02:41,746 as delicate nebulae, slowly blowing into space by dying stars, 39 00:02:41,747 --> 00:02:48,254 or as titanic supernova explosions that almost outshine their home galaxy. 40 00:02:48,255 --> 00:02:54,197 Deep in the Orion Nebula, Hubble even saw the breeding ground of new solar systems: 41 00:02:54,198 --> 00:02:57,268 dusty discs around newborn stars 42 00:02:57,269 --> 00:02:59,828 that may soon condense into planets. 43 00:02:59,829 --> 00:03:05,130 The space telescope studied thousands of individual stars in giant globular clusters, 44 00:03:05,131 --> 00:03:08,837 the oldest stellar families in the Universe. 45 00:03:09,534 --> 00:03:11,998 And galaxies, of course. 46 00:03:11,999 --> 00:03:15,861 Never before had astronomers seen so much detail. 47 00:03:15,862 --> 00:03:23,115 Majestic spirals, absorbing dust lanes, violent collisions. 48 00:03:24,910 --> 00:03:28,411 Extremely long exposures of blank regions of sky 49 00:03:28,412 --> 00:03:33,634 even revealed thousands of faint galaxies billions of light-years away. 50 00:03:33,635 --> 00:03:37,736 Photons that were emitted when the Universe was still young. 51 00:03:37,737 --> 00:03:44,816 A window into the distant past, shedding new light on the ever-evolving cosmos. 52 00:03:45,790 --> 00:03:48,783 Hubble is not the only telescope in space. 53 00:03:48,784 --> 00:03:53,400 This is NASA's Spitzer Space Telescope, launched in August 2003. 54 00:03:53,401 --> 00:03:57,329 In a way, it is Hubble's equivalent for the infrared. 55 00:03:57,330 --> 00:04:01,534 Spitzer has a mirror that is only 85 centimetres across. 56 00:04:01,535 --> 00:04:06,274 But the telescope is hiding behind a heat shield that protects it from the Sun. 57 00:04:06,275 --> 00:04:10,851 And its detectors are tucked away in a Dewar filled with liquid helium. 58 00:04:10,852 --> 00:04:15,358 Here the detectors are cooled down to just a few degrees above absolute zero 59 00:04:15,359 --> 00:04:18,446 making them very, very sensitive. 60 00:04:19,133 --> 00:04:22,446 Spitzer has revealed a dusty Universe. 61 00:04:22,447 --> 00:04:28,070 Dark, opaque clouds of dust glow in the infrared when heated from within. 62 00:04:28,071 --> 00:04:30,496 Shock waves from galaxy collisions 63 00:04:30,497 --> 00:04:34,133 sweep up dust in telltale rings and tidal features, 64 00:04:34,134 --> 00:04:36,939 new sites for ubiquitous star formation. 65 00:04:39,185 --> 00:04:42,979 Dust is also produced in the aftermath of a star's death. 66 00:04:42,980 --> 00:04:46,310 Spitzer found that planetary nebulae and supernova remnants 67 00:04:46,311 --> 00:04:51,573 are laden with dust particles, the prerequisite building blocks of future planets. 68 00:04:52,126 --> 00:04:53,713 At other infrared wavelengths, 69 00:04:53,714 --> 00:04:56,515 Spitzer can also see right trough a dust cloud, 70 00:04:56,516 --> 00:05:00,727 revealing the stars inside, hidden in their dark cores. 71 00:05:01,569 --> 00:05:04,271 Finally, the space telescope's spectrographs 72 00:05:04,272 --> 00:05:07,040 have studied the atmospheres of extra-solar planets, 73 00:05:07,041 --> 00:05:12,353 gas giants like Jupiter, that race around their parent stars in just a few days. 74 00:05:13,886 --> 00:05:16,784 So what about X-rays and gamma rays? 75 00:05:16,785 --> 00:05:19,465 Well, they're completely blocked by the Earth's atmosphere. 76 00:05:19,466 --> 00:05:22,895 And so without space telescopes, astronomers would be totally blind 77 00:05:22,896 --> 00:05:25,846 to these energetic forms of radiation. 78 00:05:27,385 --> 00:05:33,003 X-ray and gamma ray space telescopes reveal the hot, energetic and violent Universe 79 00:05:33,004 --> 00:05:39,027 of galaxy clusters, black holes, supernova explosions and galaxy collisions. 80 00:05:42,472 --> 00:05:44,487 They're very hard to build, though. 81 00:05:44,488 --> 00:05:48,099 Energetic radiation passes right through a conventional mirror. 82 00:05:48,100 --> 00:05:53,449 X-ray can only be focused with nested mirror shells made of pure gold. 83 00:05:53,450 --> 00:05:56,786 And gamma rays are studies with sophisticated pinhole cameras, 84 00:05:56,787 --> 00:06:00,205 or stacked scintillators that give off brief flashes of normal light 85 00:06:00,206 --> 00:06:02,842 when struck by a gamma ray photon. 86 00:06:04,861 --> 00:06:08,962 In the 1990s, NASA operated the Compton Gamma Ray Observatory. 87 00:06:08,963 --> 00:06:13,730 At the time, it was the largest and most massive scientific satellite ever launched. 88 00:06:13,731 --> 00:06:16,699 A fully fledged physics lab in space. 89 00:06:16,700 --> 00:06:20,042 In 2008, Compton was succeeded by GLAST: 90 00:06:20,043 --> 00:06:23,468 the Gamma Ray Large Area Space Telescope. 91 00:06:24,240 --> 00:06:29,831 It will study everything in the high-energy Universe from dark matter to pulsars. 92 00:06:32,234 --> 00:06:36,310 Meanwhile, astronomers have two X-ray telescopes in space. 93 00:06:36,311 --> 00:06:41,133 NASA's Chandra X-ray Observatory and ESA's XMM-Newton Observatory 94 00:06:41,134 --> 00:06:44,932 are both studying the hottest places in the Universe. 95 00:06:47,573 --> 00:06:51,218 This is what the sky looks like with X-ray vision. 96 00:06:51,219 --> 00:06:54,139 Extended features are clouds of gas, 97 00:06:54,140 --> 00:06:58,649 heated to millions of degrees by shock waves in supernova remnants. 98 00:06:59,029 --> 00:07:02,271 The bright point sources are X-rays binaries: 99 00:07:02,272 --> 00:07:07,044 neutron stars or black holes that suck in matter from a companion star. 100 00:07:07,372 --> 00:07:11,077 This hot, in falling gas emits X-rays. 101 00:07:11,112 --> 00:07:14,944 Likewise, X-ray telescopes reveal super-massive black holes 102 00:07:14,945 --> 00:07:17,443 in the cores of distant galaxies. 103 00:07:17,444 --> 00:07:21,508 Matter that spirals inward gets hot enough to glow in X-rays 104 00:07:21,509 --> 00:07:25,723 just before it plunges into the black hole and out of sight. 105 00:07:25,724 --> 00:07:32,000 Hot but tenuous gas also fills the space between individual galaxies in a cluster. 106 00:07:32,001 --> 00:07:35,883 Sometimes, this intra-cluster gas is shocked and heated even more 107 00:07:35,884 --> 00:07:38,950 by colliding and merging galaxy clusters. 108 00:07:40,113 --> 00:07:43,157 Even more exciting are gamma ray bursts, 109 00:07:43,158 --> 00:07:45,935 the most energetic events in the Universe. 110 00:07:45,936 --> 00:07:52,482 These are catastrophic terminal explosions of very massive, rapidly spinning stars. 111 00:07:52,483 --> 00:07:58,750 In less than a second, they release more energy than the Sun does in 10 billion years. 112 00:08:01,927 --> 00:08:08,298 Hubble, Spitzer, Chandra, XMM-Newton and GLAST are all versatile giants. 113 00:08:08,299 --> 00:08:10,687 But some space telescopes are much smaller 114 00:08:10,688 --> 00:08:13,154 and have much more focused missions. 115 00:08:13,155 --> 00:08:14,961 Take COROT, for example. 116 00:08:14,962 --> 00:08:18,312 This French satellite is devoted to stellar seismology 117 00:08:18,313 --> 00:08:20,505 and the study of extra-solar planets. 118 00:08:20,506 --> 00:08:25,128 Or NASA's Swift satellite, a combined X-ray and gamma ray observatory 119 00:08:25,129 --> 00:08:28,627 designed to unravel the mysteries of gamma ray bursts. 120 00:08:29,866 --> 00:08:33,847 And then there's WMAP, the Wilkinson Microwave Anisotropy Probe. 121 00:08:33,848 --> 00:08:35,960 In just over two years in space, 122 00:08:35,961 --> 00:08:40,910 it had already map the cosmic background radiation to unprecedented detail. 123 00:08:40,911 --> 00:08:43,907 WMAP gives cosmologists the best view yet 124 00:08:43,908 --> 00:08:49,328 of one of the earliest phases of the Universe more than 13 billion years ago. 125 00:08:50,699 --> 00:08:54,192 Opening up the space frontier has been one of the most exciting developments 126 00:08:54,193 --> 00:08:56,323 in the history of the telescope. 127 00:08:56,324 --> 00:08:58,356 So what's next? 128 00:09:00,422 --> 00:09:04,372 Thank you for joining me in this sixth episode of the special series. 129 00:09:04,373 --> 00:09:08,245 Next time we will see the new and amazing telescopes of the future 130 00:09:08,246 --> 00:09:10,095 that are currently being planned. 131 00:09:10,096 --> 00:09:13,034 This is Dr. J signing off for the Hubblecast. 132 00:09:13,069 --> 00:09:17,853 Once again, nature has surprised us beyond our wildest imagination... 133 00:09:17,854 --> 00:09:19,854 Hubblecast is produced by ESA / Hubble 134 00:09:19,855 --> 00:09:21,855 at the European Southern Observatory in Germany. 135 00:09:23,122 --> 00:09:25,122 The Hubble mission is a project of international cooperation 136 00:09:25,123 --> 00:09:27,123 between NASA and the European Space Agency.