Welcome to brain Stuff production of I Heart Radio. Hey brain Stuff, Lauren vocal bomb here. Dark matter sounds a little mysterious because it is. It's stuff we can't see with any existing telescopes, but that math and physics tells us must exist based on the way that normal matter, the stuff we can see, behaves, and there's a lot
of dark matter out there. Astrophysicists think that about of the universe is made up of dark matter compared with only five percent normal matter, meaning that the term normal probably isn't the most accurate. Dark matter is the bedrock that all galaxies are anchored too. You can't get one without the other, or so we thought, until astronomers found ghostly galaxy that doesn't appear to contain any dark matter.
It's as if the universe is playing a trick on us by flipping the laws of physics on their head. Dark matter should be there, but isn't. It's a game change your galaxy, astronomers are saying, and it's like nothing we've ever seen before. We may not be able to spot dark matter, but astronomers can measure its gravitational effects acting on normal matter. For example, they can look at
how fast stars cruise around a galaxy. When dark matter is present, that galaxy's gravity will be bulked up, causing its stars to move faster than if just normal matter were present. But in the case of n g C one oh five two dash DF two, an ultra diffuse galaxy located sixty five million light years away, astronomers have found that its stars are moving in exactly the way that would be predicted if only the total mass of
all the visible stuff is considered. In other words, dark matter doesn't seem to be exerting its gravity on normal matter in that galaxy, and that's weird, Peter Van Dulkum of Yale University said in a statement, finding a galaxy without dark matter is unexpected because this invisible, mysterious substance is the most dominant aspect of any galaxy. For decades, we thought the galaxies start their lives as blobs of dark matter. After that everything else happens. Gas falls into
the dark matter halo's the gas turns into stars. They slowly build up. Then you end up with galaxies like the Milky Way. This galaxy challenges the standard ideas of how we think galaxies form. Ultra diffuse galaxies are oddities in their own right, having only been discovered in as they are very difficult to detect. However, it appears that this class of galaxy is common, but none are like
the one in question. The galaxy was discovered using the Dragonfly Telephoto Array, a telescope in New Mexico that's custom made to seek out these elusive targets. Then, using a set of twin ten meter optical and infrared telescopes in Hawaii, the astronomers signaled out ten bright globular clusters, which are large, compact groups of stars orbiting the galaxy's core. They then
use spectral data to measure their motions. These clusters were found to be plotting along more slowly than expected, meaning there's far less mass in that galaxy then would be predicted. In fact, there's so little mass that the researchers have come to the astonishing conclusion that there's little, if any dark matter there. Follow Up observations were made with the Gemini North Telescope, also in Hawaii, so the galaxy structure
could be studied. With Gemini's help. The researchers ruled out interactions with other galaxies as being the cause of its weird dark matter deficit, Ben Docom said in the press release, if there's any dark matter at all, it's very little. The stars in the galaxy can account for all of the mass, and there doesn't seem to be any room for dark matter. This finding seems to suggest the dark matter has quote its own separate existence apart from other
components of galaxies. He added, and this makes the very existence of this galaxy and mystery. If it has no dark matter, how did even evolve into a galaxy. In their study published in March in the journal Nature, Ben Ducom's team speculates that some cataclysmic event in the galaxy may have cleared out all the dark matter and blasted
away all the star forming gases. Alternatively, a nearby massive elliptical galaxy may have played a role in the current galaxies lack of dark matter billions of years ago when it was undergoing its early and violent stages of evolution. Now, the researchers are pouring over Hubble space telescopes observations of similar galaxies to perhaps find more that lack dark matter.
If they find more, then altered, diffuse, and faint galaxies might be the norm when dark matter isn't press it, and that's a fascinating development in our understanding of how galaxies evolve. Ben Docom concluded, every galaxy we do about before has dark matter, and they all fall in familiar categories like spiral or elliptical galaxies. But what would you get if there was no dark matter at all? Maybe this is what you would get. Today's episode was written
by dr Ian O'Neill and produced by Tyler Clang. Brain Stuff is a production of iHeart Radio's How Stuff Works. For more on this and lots of other dark topics, visit our home planet, how stuff Works dot com, and for more podcasts from my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.