1 00:00:19,000 --> 00:00:20,000 This is the Hubblecast! 2 00:00:20,000 --> 00:00:23,000 News and images from the NASA/ESA Hubble Space Telescope. 3 00:00:23,000 --> 00:00:30,000 Travelling through time and space with our host Doctor J, a.k.a. Dr. Joe Liske. 4 00:00:30,000 --> 00:00:37,000 Welcome to the sixth special episode of the Hubblecast celebrating the International Year of Astronomy in 2009. 5 00:00:37,000 --> 00:00:44,000 In the fifth episode, we saw how some telescopes study parts of the universe that we can’t see with our eyes. 6 00:00:44,000 --> 00:00:50,000 This time, we will see how telescopes in space have revolutionised almost every field in astronomy. 7 00:00:52,000 --> 00:00:53,000 The Hubble Space Telescope. 8 00:00:53,000 --> 00:00:58,000 Is by far the most famous telescope in history. And for good reason. 9 00:00:58,000 --> 00:01:01,000 Hubble has revolutionised so many fields in astronomy. 10 00:01:01,000 --> 00:01:05,000 By modern standards, Hubble’s mirror is actually quite small. 11 00:01:05,000 --> 00:01:08,000 It only measures about 2.4 metres across. 12 00:01:08,000 --> 00:01:11,000 But its location is literally out of this world. 13 00:01:11,000 --> 00:01:18,000 High above the blurring effects of the atmosphere, it has an exceptionally sharp view of the Universe. 14 00:01:18,000 --> 00:01:22,000 And what’s more, Hubble can see ultraviolet and near-infrared light. 15 00:01:22,000 --> 00:01:28,000 This light just cannot be seen by ground-based telescopes because it is blocked by the atmosphere. 16 00:01:29,000 --> 00:01:37,000 Cameras and spectrographs, some as big as a telephone booth, dissect and register the light from distant cosmic shores. 17 00:01:38,000 --> 00:01:42,000 Just like any ground-based telescope, Hubble is upgraded from time to time. 18 00:01:42,000 --> 00:01:45,000 Spacewalking astronauts carry out servicing missions. 19 00:01:45,000 --> 00:01:52,000 Broken parts get refurbished and older instruments get replaced with newer and state-of-the-art technology. 20 00:01:53,000 --> 00:01:56,000 Hubble has become the powerhouse of observational astronomy. 21 00:01:56,000 --> 00:02:00,000 And it has transformed our understanding of the cosmos. 22 00:02:03,000 --> 00:02:07,000 With its keen eyesight, Hubble observed seasonal changes on Mars... 23 00:02:09,000 --> 00:02:11,000 a cometary impact on Jupiter... 24 00:02:14,000 --> 00:02:16,000 an edge-on view of Saturn’s rings... 25 00:02:21,000 --> 00:02:23,000 and even the surface of tiny Pluto. 26 00:02:24,000 --> 00:02:33,000 It revealed the life cycle of stars, from their very birth and baby days in a nursery of dust-laden clouds of gas, 27 00:02:33,000 --> 00:02:36,000 all the way to their final farewell: 28 00:02:36,000 --> 00:02:41,000 as delicate nebulae, slowly blown into space by dying stars, 29 00:02:41,000 --> 00:02:48,000 or as titanic supernova explosions that almost outshine their home galaxy. 30 00:02:49,000 --> 00:02:54,000 Deep in the Orion Nebula, Hubble even saw the breeding ground of new solar systems: 31 00:02:54,000 --> 00:02:59,000 dusty discs around newborn stars that may soon condense into planets. 32 00:02:59,000 --> 00:03:08,000 The space telescope studied thousands of individual stars in giant globular clusters, the oldest stellar families in the Universe. 33 00:03:10,000 --> 00:03:11,000 And galaxies, of course. 34 00:03:11,000 --> 00:03:15,000 Never before had astronomers seen so much detail. 35 00:03:15,000 --> 00:03:22,000 Majestic spirals, absorbing dust lanes, violent collisions. 36 00:03:24,000 --> 00:03:28,000 Extremely long exposures of blank regions of sky 37 00:03:28,000 --> 00:03:33,000 even revealed thousands of faint galaxies billions of light-years away. 38 00:03:33,000 --> 00:03:37,000 Photons that were emitted when the Universe was still young. 39 00:03:37,000 --> 00:03:44,000 A window into the distant past, shedding new light on the ever-evolving cosmos. 40 00:03:45,000 --> 00:03:48,000 Hubble is not the only telescope in space. 41 00:03:48,000 --> 00:03:53,000 This is NASA’s Spitzer Space Telescope, launched in August 2003. 42 00:03:53,000 --> 00:03:56,000 In a way, it is Hubble’s equivalent for the infrared. 43 00:03:57,000 --> 00:04:01,000 Spitzer has mirror that is only 85 centimetres across. 44 00:04:01,000 --> 00:04:05,000 But the telescope is hiding behind a heat shield that protects it from the Sun. 45 00:04:05,000 --> 00:04:10,000 And its detectors are tucked away in a dewar filled with liquid helium. 46 00:04:10,000 --> 00:04:18,000 Here the detectors are cooled down to just a few degrees above absolute zero making them very, very sensitive. 47 00:04:19,000 --> 00:04:22,000 Spitzer has revealed a dusty Universe. 48 00:04:22,000 --> 00:04:27,000 Dark, opaque clouds of dust glow in the infrared when heated from within. 49 00:04:27,000 --> 00:04:33,000 Shock waves from galaxy collisions sweep up dust in telltale rings and tidal features, 50 00:04:33,000 --> 00:04:36,000 new sites for ubiquitous star formation. 51 00:04:39,000 --> 00:04:42,000 Dust is also produced in the aftermath of a star’s death. 52 00:04:42,000 --> 00:04:48,000 Spitzer found that planetary nebulae and supernova remnants are laden with dust particles, 53 00:04:48,000 --> 00:04:51,000 the prerequisite building blocks of future planets. 54 00:04:51,000 --> 00:04:56,000 At other infrared wavelengths, Spitzer can also see right through a dust cloud, 55 00:04:56,000 --> 00:05:00,000 revealing the stars inside, hidden in their dark cores. 56 00:05:01,000 --> 00:05:06,000 Finally, the space telescope’s spectrographs have studied the atmospheres of extrasolar planets – 57 00:05:06,000 --> 00:05:11,000 gas giants like Jupiter, that race around their parent stars in just a few days. 58 00:05:14,000 --> 00:05:16,000 So what about X-rays and gamma rays? 59 00:05:16,000 --> 00:05:19,000 Well, they are completely blocked by the Earth’s atmosphere. 60 00:05:19,000 --> 00:05:25,000 And so without space telescopes, astronomers would be totally blind to these energetic forms of radiation. 61 00:05:27,000 --> 00:05:32,000 X-ray and gamma ray space telescopes reveal the hot, energetic and violent Universe 62 00:05:32,000 --> 00:05:38,000 of galaxy clusters, black holes, supernova explosions, and galaxy collisions. 63 00:05:42,000 --> 00:05:44,000 They are very hard to build, though. 64 00:05:44,000 --> 00:05:47,000 Energetic radiation passes right through a conventional mirror. 65 00:05:47,000 --> 00:05:53,000 X-rays can only be focused with nested mirror shells made of pure gold. 66 00:05:53,000 --> 00:05:56,000 And gamma rays are studied with sophisticated pinhole cameras, 67 00:05:56,000 --> 00:06:02,000 or stacked scintillators that give off brief flashes of normal light when struck by a gamma ray photon. 68 00:06:05,000 --> 00:06:08,000 In the 1990s, NASA operated the Compton Gamma Ray Observatory. 69 00:06:08,000 --> 00:06:13,000 At the time, it was the largest and most massive scientific satellite ever launched. 70 00:06:13,000 --> 00:06:16,000 A fully fledged physics lab in space. 71 00:06:16,000 --> 00:06:20,000 In 2008, Compton was succeeded by GLAST: 72 00:06:20,000 --> 00:06:23,000 the Gamma Ray Large Area Space Telescope. 73 00:06:24,000 --> 00:06:29,000 It will study everything in the high-energy Universe from dark matter to pulsars. 74 00:06:32,000 --> 00:06:36,000 Meanwhile, astronomers have two X-ray telescopes in space. 75 00:06:36,000 --> 00:06:38,000 NASA’s Chandra X-ray Observatory 76 00:06:38,000 --> 00:06:44,000 and ESA’s XMM-Newton Observatory are both studying the hottest places in the Universe. 77 00:06:47,000 --> 00:06:51,000 This is what the sky looks like with X-ray vision. 78 00:06:51,000 --> 00:06:53,000 Extended features are clouds of gas, 79 00:06:53,000 --> 00:06:58,000 heated to millions of degrees by shock waves in supernova remnants. 80 00:06:59,000 --> 00:07:02,000 The bright point sources are X-ray binaries: 81 00:07:02,000 --> 00:07:07,000 neutron stars or black holes that suck in matter from a companion star. 82 00:07:07,000 --> 00:07:11,000 This hot, in falling gas emits X-rays. 83 00:07:11,000 --> 00:07:17,000 Likewise, X-ray telescopes reveal supermassive black holes in the cores of distant galaxies. 84 00:07:17,000 --> 00:07:21,000 Matter that spirals inward gets hot enough to glow in X-rays 85 00:07:21,000 --> 00:07:25,000 just before it plunges into the black hole and out of sight. 86 00:07:25,000 --> 00:07:31,000 Hot but tenuous gas also fills the space between individual galaxies in a cluster. 87 00:07:31,000 --> 00:07:39,000 Sometimes, this intracluster gas is shocked and heated even more by colliding and merging galaxy clusters. 88 00:07:39,000 --> 00:07:46,000 Even more exciting are gamma ray bursts, the most energetic events in the Universe. 89 00:07:46,000 --> 00:07:52,000 These are catastrophic terminal explosions of very massive, rapidly spinning stars. 90 00:07:52,000 --> 00:07:58,000 In less than a second, they release more energy than the Sun does in 10 billion years. 91 00:08:02,000 --> 00:08:08,000 Hubble, Spitzer, Chandra, XMM-Newton and GLAST are all versatile giants. 92 00:08:08,000 --> 00:08:13,000 But some space telescopes are much smaller and have much more focused missions. 93 00:08:13,000 --> 00:08:14,000 Take COROT, for example. 94 00:08:14,000 --> 00:08:20,000 This French satellite is devoted to stellar seismology and the study of extrasolar planets. 95 00:08:20,000 --> 00:08:22,000 Or NASA’s Swift satellite, 96 00:08:22,000 --> 00:08:28,000 a combined X-ray and gamma ray observatory designed to unravel the mystery of gamma ray bursts. 97 00:08:29,000 --> 00:08:34,000 And then there’s WMAP, the Wilkinson Microwave Anisotropy Probe. 98 00:08:34,000 --> 00:08:40,000 In just over two years in space, it had already mapped the cosmic background radiation to unprecedented detail. 99 00:08:40,000 --> 00:08:46,000 WMAP gave cosmologists the best view yet of one of the earliest phases of the Universe, 100 00:08:46,000 --> 00:08:49,000 more than 13 billion years ago. 101 00:08:50,000 --> 00:08:55,000 Opening up the space frontier has been one of the most exciting developments in the history of the telescope. 102 00:08:55,000 --> 00:08:57,000 So what’s next? 103 00:09:00,000 --> 00:09:04,000 Thank you for joining me in this sixth episode of the special series. 104 00:09:04,000 --> 00:09:10,000 Next time we will see the new and amazing telescopes of the future that are currently being planned. 105 00:09:10,000 --> 00:09:12,000 This is Dr. J. signing off for the Hubblecast. 106 00:09:12,000 --> 00:09:17,000 Once again nature has surprised us beyond our wildest imagination.