1 00:00:01,920 --> 00:00:07,160 Speaker 1: Welcome to brain Stuff production of iHeart Radio. Hey, brain Stuff, 2 00:00:07,200 --> 00:00:10,399 Speaker 1: Lauren Vogel bomb Here. An event horizon is the point 3 00:00:10,400 --> 00:00:13,960 Speaker 1: of no return, a spherical region surrounding the gaping maw 4 00:00:14,040 --> 00:00:16,800 Speaker 1: of a black hole, beyond which nothing, not even light 5 00:00:16,920 --> 00:00:20,640 Speaker 1: can escape. We have no idea what mysteries lie inside, 6 00:00:20,840 --> 00:00:23,320 Speaker 1: but we do know that our universe ends abruptly at 7 00:00:23,320 --> 00:00:28,440 Speaker 1: this terrifying boundary into the unknown. Now, after two decades 8 00:00:28,440 --> 00:00:31,680 Speaker 1: of international collaboration, some of the world's most powerful radio 9 00:00:31,680 --> 00:00:34,560 Speaker 1: telescopes have captured an image of a supermassive black hole's 10 00:00:34,600 --> 00:00:38,120 Speaker 1: event horizon. By doing so, they proved that the predictions 11 00:00:38,159 --> 00:00:41,640 Speaker 1: arising from Einstein's theory of general relativity are valid even 12 00:00:41,680 --> 00:00:46,120 Speaker 1: in the most extreme cosmic environment possible. The black hole 13 00:00:46,159 --> 00:00:48,080 Speaker 1: in the image lurks in the center of the massive 14 00:00:48,080 --> 00:00:51,839 Speaker 1: elliptical galaxy Messier eighty seven, in the constellation Virgo, some 15 00:00:52,000 --> 00:00:55,120 Speaker 1: fifty five million light years distant. The release of the 16 00:00:55,120 --> 00:00:58,120 Speaker 1: image was highly anticipated all over the world and published 17 00:00:58,120 --> 00:01:01,160 Speaker 1: in several studies appearing in the journal Astro Physical Journal Letters. 18 00:01:02,080 --> 00:01:05,880 Speaker 1: Supermassive black holes dictate the evolution of the galaxies they inhabit, 19 00:01:06,200 --> 00:01:08,720 Speaker 1: so a direct look at this one's event horizon could 20 00:01:08,800 --> 00:01:11,960 Speaker 1: open a new window of understanding into how these behemoths work. 21 00:01:12,520 --> 00:01:15,560 Speaker 1: And this monstrous object is quite the specimen. It has 22 00:01:15,600 --> 00:01:18,720 Speaker 1: a whopping mass of six point five billion sons, all 23 00:01:18,760 --> 00:01:21,840 Speaker 1: crammed into an event horizon measuring nearly half a light 24 00:01:21,920 --> 00:01:26,319 Speaker 1: day across. Despite its incredible size and mass, no single 25 00:01:26,360 --> 00:01:29,600 Speaker 1: telescope on the planet could capture its portrait. It's simply 26 00:01:29,600 --> 00:01:32,880 Speaker 1: too far away to resolve. To remedy this, astronomers used 27 00:01:32,880 --> 00:01:36,240 Speaker 1: a method known as very long baseline interferometry to combine 28 00:01:36,280 --> 00:01:39,039 Speaker 1: the collective observing power of eight of the world's most 29 00:01:39,080 --> 00:01:42,880 Speaker 1: powerful radio telescopes to do the job. The event Horizon 30 00:01:42,959 --> 00:01:46,000 Speaker 1: Telescope is a virtual telescope as wide as our planet 31 00:01:46,280 --> 00:01:48,800 Speaker 1: and powerful enough to capture the first glimpse of one 32 00:01:48,840 --> 00:01:51,520 Speaker 1: of the most massive black holes known to exist. It 33 00:01:51,520 --> 00:01:53,600 Speaker 1: took a team of more than two hundred researchers to 34 00:01:53,640 --> 00:01:58,600 Speaker 1: accomplish this feat. Although black holes are well black, should 35 00:01:58,600 --> 00:02:01,360 Speaker 1: there be any matter close to the event horizon, extreme 36 00:02:01,400 --> 00:02:05,000 Speaker 1: friction in the relativistic environment will rip electrons from atoms, 37 00:02:05,040 --> 00:02:08,800 Speaker 1: creating a powerful fireworks display, and this is why the 38 00:02:08,800 --> 00:02:12,440 Speaker 1: event Horizon Telescope's first image shows a dark circle surrounded 39 00:02:12,440 --> 00:02:15,839 Speaker 1: by a bright ring of emissions. These emissions are being 40 00:02:15,840 --> 00:02:18,880 Speaker 1: produced just outside the black hole's event horizon, where the 41 00:02:18,960 --> 00:02:22,400 Speaker 1: extremely hot gases orbiting it are heated to several billions 42 00:02:22,400 --> 00:02:25,520 Speaker 1: of degrees kelvin, with the event horizon itself appearing as 43 00:02:25,520 --> 00:02:29,560 Speaker 1: a silhouetted dark disc against a bright background. Features that 44 00:02:29,600 --> 00:02:33,120 Speaker 1: confirm what theoretical physicists could only predict up until now. 45 00:02:33,600 --> 00:02:37,840 Speaker 1: Surely a dramatic moment for those theorists, this is possibly 46 00:02:37,880 --> 00:02:41,239 Speaker 1: the most profound outcome of the event horizon telescopes observation. 47 00:02:41,800 --> 00:02:44,400 Speaker 1: All of the theoretical predictions for what the event horizon 48 00:02:44,480 --> 00:02:47,680 Speaker 1: telescope might see are based on the framework of Einstein's 49 00:02:47,720 --> 00:02:50,960 Speaker 1: general relativity, a theory that has proven robust since its 50 00:02:50,960 --> 00:02:54,120 Speaker 1: formulation more than a hundred years ago. On seeing this 51 00:02:54,200 --> 00:02:57,640 Speaker 1: first image, physicists remarked on how precisely the reality of 52 00:02:57,680 --> 00:03:02,120 Speaker 1: the black hole's event horizon matches the actions of general relativity, 53 00:03:02,600 --> 00:03:05,840 Speaker 1: and this first image is just that the first. The 54 00:03:05,840 --> 00:03:09,680 Speaker 1: event horizon telescope collaboration will continue observing Messier eighty seven 55 00:03:09,840 --> 00:03:12,400 Speaker 1: and a second target, the supermassive black hole in the 56 00:03:12,440 --> 00:03:15,760 Speaker 1: center of our galaxy, A four million solar mass object 57 00:03:15,800 --> 00:03:21,400 Speaker 1: called Sagittarius A. Counterintuitively, although Sagittarius A is comparatively close 58 00:03:21,600 --> 00:03:24,680 Speaker 1: only twenty light years away two thousand times close to 59 00:03:24,760 --> 00:03:27,160 Speaker 1: us than Messi A eighty seven, it has a different 60 00:03:27,160 --> 00:03:30,600 Speaker 1: set of challenges. One problem is that as Sagittarius A 61 00:03:30,720 --> 00:03:33,840 Speaker 1: is smaller, its emissions vary over shorter time scales than 62 00:03:33,840 --> 00:03:39,040 Speaker 1: Messier eighty seven's monstrous black hole, making observations more difficult. Also, 63 00:03:39,160 --> 00:03:42,320 Speaker 1: as we are embedded inside our galaxy's disc, which contains 64 00:03:42,320 --> 00:03:45,520 Speaker 1: a lot of interstellar dust, the event horizon telescope signal 65 00:03:45,600 --> 00:03:49,800 Speaker 1: suffers more scattering, making it more challenging to resolve. As 66 00:03:49,920 --> 00:03:52,800 Speaker 1: most of the intergalactic space between us and Messier eighty 67 00:03:52,840 --> 00:03:57,160 Speaker 1: seven is pretty empty, scattering is less of a problem 68 00:03:57,240 --> 00:04:00,400 Speaker 1: when we'll see Sagittarius A. Remains to be seen, But 69 00:04:00,520 --> 00:04:03,560 Speaker 1: now that the technology behind the event horizon telescope has 70 00:04:03,560 --> 00:04:06,880 Speaker 1: been proven, our understanding of supermassive black holes is sure 71 00:04:06,920 --> 00:04:14,720 Speaker 1: to blossom. Today's episode was written by Ian O'Neill and 72 00:04:14,720 --> 00:04:17,359 Speaker 1: produced by Tyler Clang. Brain Stuff is a production of 73 00:04:17,360 --> 00:04:19,800 Speaker 1: iHeart Radio's How Stuff Works. For more on this and 74 00:04:19,839 --> 00:04:22,560 Speaker 1: lots of other supermassive topics, visit our home planet, how 75 00:04:22,600 --> 00:04:25,240 Speaker 1: stuff works dot com and for more podcasts. For my 76 00:04:25,320 --> 00:04:28,240 Speaker 1: heart Radio, visit the I Heart Radio app, Apple Podcasts, 77 00:04:28,279 --> 00:04:29,960 Speaker 1: or wherever you listen to your favorite shows.