1 00:00:01,920 --> 00:00:06,520 Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey 2 00:00:06,519 --> 00:00:10,079 Speaker 1: brain Stuff, Lauren vocal bomb here. Dark matter sounds a 3 00:00:10,080 --> 00:00:13,039 Speaker 1: little mysterious because it is. It's stuff we can't see 4 00:00:13,080 --> 00:00:15,800 Speaker 1: with any existing telescopes, but that math and physics tells 5 00:00:15,840 --> 00:00:17,799 Speaker 1: us must exist based on the way that normal matter, 6 00:00:17,960 --> 00:00:20,880 Speaker 1: the stuff we can see, behaves, and there's a lot 7 00:00:20,920 --> 00:00:24,799 Speaker 1: of dark matter out there. Astrophysicists think that about of 8 00:00:24,840 --> 00:00:27,479 Speaker 1: the universe is made up of dark matter compared with 9 00:00:27,520 --> 00:00:30,400 Speaker 1: only five percent normal matter, meaning that the term normal 10 00:00:30,520 --> 00:00:34,400 Speaker 1: probably isn't the most accurate. Dark matter is the bedrock 11 00:00:34,440 --> 00:00:36,919 Speaker 1: that all galaxies are anchored too. You can't get one 12 00:00:36,960 --> 00:00:40,360 Speaker 1: without the other, or so we thought, until astronomers found 13 00:00:40,440 --> 00:00:43,560 Speaker 1: ghostly galaxy that doesn't appear to contain any dark matter. 14 00:00:44,000 --> 00:00:45,559 Speaker 1: It's as if the universe is playing a trick on 15 00:00:45,640 --> 00:00:47,400 Speaker 1: us by flipping the laws of physics on their head. 16 00:00:47,760 --> 00:00:51,360 Speaker 1: Dark matter should be there, but isn't. It's a game 17 00:00:51,440 --> 00:00:54,080 Speaker 1: change your galaxy, astronomers are saying, and it's like nothing 18 00:00:54,080 --> 00:00:56,400 Speaker 1: we've ever seen before. We may not be able to 19 00:00:56,440 --> 00:00:59,400 Speaker 1: spot dark matter, but astronomers can measure its gravitational effects 20 00:00:59,440 --> 00:01:02,160 Speaker 1: acting on normal matter. For example, they can look at 21 00:01:02,160 --> 00:01:05,200 Speaker 1: how fast stars cruise around a galaxy. When dark matter 22 00:01:05,280 --> 00:01:08,479 Speaker 1: is present, that galaxy's gravity will be bulked up, causing 23 00:01:08,520 --> 00:01:10,800 Speaker 1: its stars to move faster than if just normal matter 24 00:01:10,840 --> 00:01:13,320 Speaker 1: were present. But in the case of n g C 25 00:01:13,640 --> 00:01:16,760 Speaker 1: one oh five two dash DF two, an ultra diffuse 26 00:01:16,800 --> 00:01:20,240 Speaker 1: galaxy located sixty five million light years away, astronomers have 27 00:01:20,240 --> 00:01:22,280 Speaker 1: found that its stars are moving in exactly the way 28 00:01:22,280 --> 00:01:24,440 Speaker 1: that would be predicted if only the total mass of 29 00:01:24,440 --> 00:01:27,399 Speaker 1: all the visible stuff is considered. In other words, dark 30 00:01:27,400 --> 00:01:29,760 Speaker 1: matter doesn't seem to be exerting its gravity on normal 31 00:01:29,760 --> 00:01:34,600 Speaker 1: matter in that galaxy, and that's weird, Peter Van Dulkum 32 00:01:34,680 --> 00:01:37,640 Speaker 1: of Yale University said in a statement, finding a galaxy 33 00:01:37,680 --> 00:01:41,600 Speaker 1: without dark matter is unexpected because this invisible, mysterious substance 34 00:01:41,680 --> 00:01:44,720 Speaker 1: is the most dominant aspect of any galaxy. For decades, 35 00:01:44,760 --> 00:01:46,840 Speaker 1: we thought the galaxies start their lives as blobs of 36 00:01:46,920 --> 00:01:50,600 Speaker 1: dark matter. After that everything else happens. Gas falls into 37 00:01:50,640 --> 00:01:53,280 Speaker 1: the dark matter halo's the gas turns into stars. They 38 00:01:53,320 --> 00:01:55,560 Speaker 1: slowly build up. Then you end up with galaxies like 39 00:01:55,600 --> 00:01:58,920 Speaker 1: the Milky Way. This galaxy challenges the standard ideas of 40 00:01:58,920 --> 00:02:03,400 Speaker 1: how we think galaxies form. Ultra diffuse galaxies are oddities 41 00:02:03,400 --> 00:02:06,280 Speaker 1: in their own right, having only been discovered in as 42 00:02:06,360 --> 00:02:09,480 Speaker 1: they are very difficult to detect. However, it appears that 43 00:02:09,560 --> 00:02:12,000 Speaker 1: this class of galaxy is common, but none are like 44 00:02:12,120 --> 00:02:15,160 Speaker 1: the one in question. The galaxy was discovered using the 45 00:02:15,200 --> 00:02:18,440 Speaker 1: Dragonfly Telephoto Array, a telescope in New Mexico that's custom 46 00:02:18,480 --> 00:02:21,440 Speaker 1: made to seek out these elusive targets. Then, using a 47 00:02:21,440 --> 00:02:24,600 Speaker 1: set of twin ten meter optical and infrared telescopes in Hawaii, 48 00:02:24,800 --> 00:02:28,680 Speaker 1: the astronomers signaled out ten bright globular clusters, which are large, 49 00:02:28,680 --> 00:02:32,000 Speaker 1: compact groups of stars orbiting the galaxy's core. They then 50 00:02:32,080 --> 00:02:35,240 Speaker 1: use spectral data to measure their motions. These clusters were 51 00:02:35,240 --> 00:02:38,040 Speaker 1: found to be plotting along more slowly than expected, meaning 52 00:02:38,080 --> 00:02:40,840 Speaker 1: there's far less mass in that galaxy then would be predicted. 53 00:02:41,200 --> 00:02:43,560 Speaker 1: In fact, there's so little mass that the researchers have 54 00:02:43,639 --> 00:02:46,400 Speaker 1: come to the astonishing conclusion that there's little, if any 55 00:02:46,600 --> 00:02:49,880 Speaker 1: dark matter there. Follow Up observations were made with the 56 00:02:49,880 --> 00:02:53,440 Speaker 1: Gemini North Telescope, also in Hawaii, so the galaxy structure 57 00:02:53,440 --> 00:02:56,680 Speaker 1: could be studied. With Gemini's help. The researchers ruled out 58 00:02:56,720 --> 00:02:59,280 Speaker 1: interactions with other galaxies as being the cause of its 59 00:02:59,280 --> 00:03:03,240 Speaker 1: weird dark matter deficit, Ben Docom said in the press release, 60 00:03:03,480 --> 00:03:05,680 Speaker 1: if there's any dark matter at all, it's very little. 61 00:03:05,960 --> 00:03:07,880 Speaker 1: The stars in the galaxy can account for all of 62 00:03:07,919 --> 00:03:10,079 Speaker 1: the mass, and there doesn't seem to be any room 63 00:03:10,120 --> 00:03:13,959 Speaker 1: for dark matter. This finding seems to suggest the dark 64 00:03:13,960 --> 00:03:16,920 Speaker 1: matter has quote its own separate existence apart from other 65 00:03:16,960 --> 00:03:20,440 Speaker 1: components of galaxies. He added, and this makes the very 66 00:03:20,480 --> 00:03:23,040 Speaker 1: existence of this galaxy and mystery. If it has no 67 00:03:23,160 --> 00:03:27,040 Speaker 1: dark matter, how did even evolve into a galaxy. In 68 00:03:27,080 --> 00:03:29,600 Speaker 1: their study published in March in the journal Nature, Ben 69 00:03:29,680 --> 00:03:32,680 Speaker 1: Ducom's team speculates that some cataclysmic event in the galaxy 70 00:03:32,840 --> 00:03:35,080 Speaker 1: may have cleared out all the dark matter and blasted 71 00:03:35,120 --> 00:03:39,120 Speaker 1: away all the star forming gases. Alternatively, a nearby massive 72 00:03:39,120 --> 00:03:41,520 Speaker 1: elliptical galaxy may have played a role in the current 73 00:03:41,520 --> 00:03:44,200 Speaker 1: galaxies lack of dark matter billions of years ago when 74 00:03:44,200 --> 00:03:48,200 Speaker 1: it was undergoing its early and violent stages of evolution. Now, 75 00:03:48,240 --> 00:03:51,280 Speaker 1: the researchers are pouring over Hubble space telescopes observations of 76 00:03:51,320 --> 00:03:54,400 Speaker 1: similar galaxies to perhaps find more that lack dark matter. 77 00:03:55,000 --> 00:03:57,880 Speaker 1: If they find more, then altered, diffuse, and faint galaxies 78 00:03:57,960 --> 00:04:00,040 Speaker 1: might be the norm when dark matter isn't press it, 79 00:04:00,560 --> 00:04:03,040 Speaker 1: and that's a fascinating development in our understanding of how 80 00:04:03,080 --> 00:04:07,800 Speaker 1: galaxies evolve. Ben Docom concluded, every galaxy we do about 81 00:04:07,840 --> 00:04:10,560 Speaker 1: before has dark matter, and they all fall in familiar 82 00:04:10,600 --> 00:04:13,920 Speaker 1: categories like spiral or elliptical galaxies. But what would you 83 00:04:13,920 --> 00:04:16,000 Speaker 1: get if there was no dark matter at all? Maybe 84 00:04:16,040 --> 00:04:23,520 Speaker 1: this is what you would get. Today's episode was written 85 00:04:23,520 --> 00:04:26,200 Speaker 1: by dr Ian O'Neill and produced by Tyler Clang. Brain 86 00:04:26,240 --> 00:04:28,440 Speaker 1: Stuff is a production of iHeart Radio's How Stuff Works. 87 00:04:28,680 --> 00:04:30,560 Speaker 1: For more on this and lots of other dark topics, 88 00:04:30,680 --> 00:04:33,120 Speaker 1: visit our home planet, how stuff Works dot com, and 89 00:04:33,200 --> 00:04:35,440 Speaker 1: for more podcasts from my heart Radio, visit the iHeart 90 00:04:35,520 --> 00:04:37,919 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 91 00:04:37,960 --> 00:04:38,599 Speaker 1: favorite shows.