1 00:00:00,000 --> 00:00:03,970 Using NASA’s Hubble Space Telescope, 2 00:00:03,970 --> 00:00:07,674 a team of astronomers captured the clearest image to date   3 00:00:07,674 --> 00:00:12,245 of the unexpected interstellar comet 3I/ATLAS. 4 00:00:12,245 --> 00:00:15,015 Astronomers are now able to more precisely 5 00:00:15,015 --> 00:00:19,252 estimate the size of the comet's  solid, icy nucleus. 6 00:00:19,252 --> 00:00:24,290 Its estimated diameter is no bigger than 3.5 miles across, 7 00:00:24,290 --> 00:00:28,395 but potentially as small as 1,000 feet across.  8 00:00:28,395 --> 00:00:30,663 Hubble captured a dust plume ejected 9 00:00:30,663 --> 00:00:32,866 from the Sun-warmed side of the comet, 10 00:00:32,866 --> 00:00:35,368 and the hint of a teardrop-shaped dust tail 11 00:00:35,368 --> 00:00:38,104 streaming away from the nucleus. 12 00:00:38,104 --> 00:00:41,207 This behavior is similar to that of previously seen 13 00:00:41,207 --> 00:00:45,011 Sun-bound comets originating within our solar system.  14 00:00:45,011 --> 00:00:47,847 The big difference is that this mysterious visitor 15 00:00:47,847 --> 00:00:51,651 came from an ancient and unknown realm of our Milky Way, 16 00:00:51,651 --> 00:00:54,354 launching from an  undetermined star system 17 00:00:54,354 --> 00:00:56,956 long ago and far away. 18 00:00:56,956 --> 00:01:00,560 In what may be the final chapter in its  space odyssey, 19 00:01:00,560 --> 00:01:03,229 3I/ATLAS is plunging toward the Sun 20 00:01:03,229 --> 00:01:07,567 at a staggering 130,000 miles per  hour. 21 00:01:07,567 --> 00:01:10,170 This is the highest velocity ever recorded 22 00:01:10,170 --> 00:01:12,572 for a solar system visitor. 23 00:01:12,572 --> 00:01:15,275 The comet's astonishing speed suggests   24 00:01:15,275 --> 00:01:17,510 it has traversed interstellar space 25 00:01:17,510 --> 00:01:19,579 for billions of years. 26 00:01:19,579 --> 00:01:21,081 The comet gained speed 27 00:01:21,081 --> 00:01:23,483 due to the gravitational slingshot effect 28 00:01:23,483 --> 00:01:26,453 of the stars and other objects it encountered. 29 00:01:26,453 --> 00:01:29,989 The longer 3I/ATLAS traveled  through interstellar space, 30 00:01:29,989 --> 00:01:31,991 the faster it moved. 31 00:01:31,991 --> 00:01:36,062 Hubble observations suggest that Comet 3I/ATLAS 32 00:01:36,062 --> 00:01:39,766 was likely expelled from a developing planetary system. 33 00:01:39,766 --> 00:01:42,635 This occurred as icy bodies aggregated within 34 00:01:42,635 --> 00:01:45,672 an outer disk or ring surrounding a star, 35 00:01:45,672 --> 00:01:48,541 further supporting the idea that such outer belts 36 00:01:48,541 --> 00:01:51,811 are common in planet-forming systems.  37 00:01:51,811 --> 00:01:54,914 Another possibility is that 3I/ATLAS 38 00:01:54,914 --> 00:01:56,950 is just a fragment of a small, 39 00:01:56,950 --> 00:02:00,720 icy planet that came too close to a white dwarf star, 40 00:02:00,720 --> 00:02:03,423 disintegrated under the stress of gravity,  41 00:02:03,423 --> 00:02:07,594 and sent its shards cannonballing back into space.  42 00:02:07,594 --> 00:02:10,997 3I/ATLAS is an icy fossil from a time perhaps 43 00:02:10,997 --> 00:02:13,299 before Earth even existed. 44 00:02:13,299 --> 00:02:16,069 If 3I/ATLAS has wandered among the stars 45 00:02:16,069 --> 00:02:19,439 for nearly half  of the Milky Way’s age, it could provide   46 00:02:19,439 --> 00:02:22,075 insights into the history of our galaxy 47 00:02:22,075 --> 00:02:26,146 and the processes behind our solar system’s formation.  48 00:02:26,146 --> 00:02:30,083 Comet 3I/ATLAS will make its closest approach to the Sun 49 00:02:30,083 --> 00:02:31,951 in October 2025, 50 00:02:31,951 --> 00:02:35,555 but don’t worry, it  won’t be anywhere near Earth. 51 00:02:35,555 --> 00:02:38,191 NASA's assets, including Hubble, 52 00:02:38,191 --> 00:02:40,293 the James Webb Space Telescope, 53 00:02:40,293 --> 00:02:42,896 the Transiting Exoplanet Survey Satellite, 54 00:02:42,896 --> 00:02:44,831 and the Swift Observatory, 55 00:02:44,831 --> 00:02:46,699 will closely monitor the comet 56 00:02:46,699 --> 00:02:48,668 to measure its chemical composition 57 00:02:48,668 --> 00:02:52,505 as the Sun's heat further sublimates its ices. 58 00:02:52,505 --> 00:02:55,642 Should it survive the perilous journey near the Sun, 59 00:02:55,642 --> 00:02:58,645 the chances of 3I/ATLAS experiencing  another 60 00:02:58,645 --> 00:03:02,315 close encounter with a star are incredibly remote. 61 00:03:02,315 --> 00:03:05,151 It's also possible that 3I/ATLAS, 62 00:03:05,151 --> 00:03:08,421 like many fragile comet nuclei approaching the Sun,   63 00:03:08,421 --> 00:03:11,457 could break apart or disintegrate into dust, 64 00:03:11,457 --> 00:03:13,860 bringing its existence to an end. 65 00:03:13,860 --> 00:03:16,396 Before 3I/ATLAS entered the picture, 66 00:03:16,396 --> 00:03:19,165 we detected two other interstellar visitors: 67 00:03:19,165 --> 00:03:22,202 1I/'Oumuamua in 2017 68 00:03:22,202 --> 00:03:26,005 and comet 2I/Borisov in 2019. 69 00:03:26,005 --> 00:03:28,308 With numerous advanced observatories 70 00:03:28,308 --> 00:03:29,943 now scanning the skies, 71 00:03:29,943 --> 00:03:32,512 we should find many more interstellar objects 72 00:03:32,512 --> 00:03:34,547 visiting our solar system. 73 00:03:34,547 --> 00:03:38,117 Each new discovery offers astronomers valuable insights 74 00:03:38,117 --> 00:03:40,386 into both our  own solar system 75 00:03:40,386 --> 00:03:47,126 and the distant universe beyond! 76 00:03:47,126 --> 00:04:00,340 Follow us on social media @NASAHubble 77 00:04:00,340 --> 00:04:05,011 NASA Meatball!!!