1 00:00:03,951 --> 00:00:06,865 The results of the Pale Red Dot campaign 2 00:00:07,035 --> 00:00:08,474 — the quest to find a planet 3 00:00:08,474 --> 00:00:11,594 orbiting the closest star to the Solar System — 4 00:00:11,747 --> 00:00:13,693 have now been announced. 5 00:00:14,420 --> 00:00:16,766 Astronomers have found clear evidence 6 00:00:16,766 --> 00:00:20,231 of a planet orbiting the star Proxima Centauri. 7 00:00:21,063 --> 00:00:24,812 This alien world is the closest possible abode 8 00:00:24,812 --> 00:00:27,759 for life outside the Solar System! 9 00:00:32,388 --> 00:00:34,784 This is the ESOcast! 10 00:00:34,796 --> 00:00:38,570 Cutting edge science and life behind the scenes at ESO, 11 00:00:38,963 --> 00:00:41,795 the European Southern Observatory. 12 00:00:53,800 --> 00:00:56,510 The search for other worlds has captivated 13 00:00:56,510 --> 00:00:58,879 imaginations throughout history, 14 00:00:59,567 --> 00:01:02,379 but only recently have we had the instruments 15 00:01:02,379 --> 00:01:06,023 able to detect worlds outside the Solar System. 16 00:01:07,608 --> 00:01:11,025 These extrasolar planets, or exoplanets, 17 00:01:11,025 --> 00:01:14,576 went undetected until 25 years ago. 18 00:01:15,281 --> 00:01:19,273 Today, thanks to advances in telescope technology, 19 00:01:19,273 --> 00:01:23,118 astronomers have detected over three thousand. 20 00:01:23,538 --> 00:01:25,505 And now the scientists behind 21 00:01:25,505 --> 00:01:27,408 the Pale Red Dot campaign 22 00:01:27,538 --> 00:01:30,242 have made a milestone discovery. 23 00:01:31,037 --> 00:01:33,629 They have discovered clear evidence for 24 00:01:33,629 --> 00:01:38,175 a potentially habitable planet orbiting Proxima Centauri, 25 00:01:38,475 --> 00:01:41,460 the closest star to the Solar System. 26 00:01:44,417 --> 00:01:46,476 Using the HARPS spectrograph 27 00:01:46,476 --> 00:01:50,914 on ESO’s 3.6 metre telescope at La Silla in Chile, 28 00:01:50,950 --> 00:01:55,000 astronomers spent the first half of 2016 looking 29 00:01:55,000 --> 00:01:57,905 for the tiny back and forth wobble of the star 30 00:01:58,143 --> 00:02:02,195 caused by the gravitational pull of an orbiting planet. 31 00:02:06,000 --> 00:02:08,400 They were trying to build on 16 years 32 00:02:08,400 --> 00:02:10,105 of earlier observations 33 00:02:10,105 --> 00:02:12,600 that hinted of the presence of a planet, 34 00:02:12,600 --> 00:02:14,271 but were inconclusive. 35 00:02:15,327 --> 00:02:17,506 Combining the data with observations 36 00:02:17,506 --> 00:02:20,165 from a network of telescopes around the world, 37 00:02:20,250 --> 00:02:22,219 the researchers confirmed 38 00:02:22,219 --> 00:02:24,692 the detection of an alien world. 39 00:02:25,608 --> 00:02:29,920 It’s at least 1.3 times as massive as the Earth 40 00:02:30,116 --> 00:02:35,248 and orbits Proxima Centauri every 11.2 days. 41 00:02:36,833 --> 00:02:40,843 It was no easy task to identify the planet, however. 42 00:02:41,400 --> 00:02:43,834 Red dwarfs like Proxima Centauri 43 00:02:43,834 --> 00:02:46,610 are active stars prone to flares, 44 00:02:46,820 --> 00:02:48,627 and can vary in ways that would 45 00:02:48,627 --> 00:02:50,779 mimic the presence of a planet. 46 00:02:51,602 --> 00:02:53,885 To exclude this possibility, 47 00:02:54,295 --> 00:02:57,531 the team carefully monitored the brightness of the star 48 00:02:57,531 --> 00:02:59,491 with a network of telescopes 49 00:02:59,491 --> 00:03:04,179 to ensure they didn’t misidentify such an important discovery. 50 00:03:07,782 --> 00:03:11,037 Perhaps the most exciting aspect of this research 51 00:03:11,100 --> 00:03:14,365 is that the exoplanet, called Proxima b, 52 00:03:14,601 --> 00:03:18,158 orbits within the habitable zone of its star. 53 00:03:19,008 --> 00:03:21,817 This means that liquid water could exist 54 00:03:21,817 --> 00:03:23,318 on the planet’s surface. 55 00:03:24,585 --> 00:03:27,797 If it were much closer the heat from the star 56 00:03:27,797 --> 00:03:29,709 would boil the water away. 57 00:03:30,306 --> 00:03:32,083 And if it were further out 58 00:03:32,083 --> 00:03:35,009 the planet’s water would freeze solid. 59 00:03:35,876 --> 00:03:39,402 Since liquid water is essential for life as we know it, 60 00:03:39,744 --> 00:03:43,429 this makes Proxima b the closest exoplanet 61 00:03:43,429 --> 00:03:46,006 to Earth that may harbour life. 62 00:03:48,251 --> 00:03:51,820 However, the same stellar activity that made Proxima b 63 00:03:51,820 --> 00:03:53,566 so difficult to spot 64 00:03:53,566 --> 00:03:57,790 could also make it an inhospitable abode for life — 65 00:03:58,505 --> 00:04:00,709 the planet’s surface is bathed 66 00:04:00,709 --> 00:04:04,289 by intense ultraviolet and X-ray radiation. 67 00:04:04,592 --> 00:04:06,231 The planet also orbits 68 00:04:06,231 --> 00:04:08,952 Proxima Centauri extremely closely, 69 00:04:08,952 --> 00:04:12,233 only 5% of the Earth Sun distance. 70 00:04:12,265 --> 00:04:15,612 It is still a matter of debate whether a planet 71 00:04:15,612 --> 00:04:18,967 so close to its star could support life. 72 00:04:28,116 --> 00:04:30,781 Proxima b’s closeness to the Earth 73 00:04:30,781 --> 00:04:33,098 makes it an intriguing target 74 00:04:33,098 --> 00:04:35,993 in the search for extraterrestrial life. 75 00:04:37,025 --> 00:04:39,552 Astronomers will use the next generation 76 00:04:39,552 --> 00:04:40,479 of telescopes 77 00:04:40,479 --> 00:04:44,229 such as ESO’s European Extremely Large Telescope 78 00:04:44,317 --> 00:04:45,771 to make an intensive study 79 00:04:45,771 --> 00:04:48,173 of this fascinating alien world 80 00:04:48,173 --> 00:04:51,033 in the hope of finding evidence of life 81 00:04:51,033 --> 00:04:53,376 elsewhere in the Universe. 82 00:04:53,939 --> 00:04:57,686 And if interstellar probes become a reality 83 00:04:58,289 --> 00:05:01,984 Proxima b may be their first destination. 84 00:05:06,791 --> 00:05:09,235 Scientific knowledge of exoplanets has grown 85 00:05:09,235 --> 00:05:12,590 has grown hugely in the last 25 years. 86 00:05:13,348 --> 00:05:14,800 With this discovery, 87 00:05:14,939 --> 00:05:18,259 and armed with ESO’s next generation telescope, 88 00:05:18,260 --> 00:05:20,619 we may soon be within reach 89 00:05:20,619 --> 00:05:23,355 of answering the age old question — 90 00:05:23,539 --> 00:05:25,246 are we alone? 91 00:05:44,387 --> 00:05:49,571 Transcription by ESO; translation by —