Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey
Speaker 1: brain Stuff, Lauren vocal bomb here. Dark matter sounds a
Speaker 1: little mysterious because it is. It's stuff we can't see
Speaker 1: with any existing telescopes, but that math and physics tells
Speaker 1: us must exist based on the way that normal matter,
Speaker 1: the stuff we can see, behaves, and there's a lot
Speaker 1: of dark matter out there. Astrophysicists think that about of
Speaker 1: the universe is made up of dark matter compared with
Speaker 1: only five percent normal matter, meaning that the term normal
Speaker 1: probably isn't the most accurate. Dark matter is the bedrock
Speaker 1: that all galaxies are anchored too. You can't get one
Speaker 1: without the other, or so we thought, until astronomers found
Speaker 1: ghostly galaxy that doesn't appear to contain any dark matter.
Speaker 1: It's as if the universe is playing a trick on
Speaker 1: us by flipping the laws of physics on their head.
Speaker 1: Dark matter should be there, but isn't. It's a game
Speaker 1: change your galaxy, astronomers are saying, and it's like nothing
Speaker 1: we've ever seen before. We may not be able to
Speaker 1: spot dark matter, but astronomers can measure its gravitational effects
Speaker 1: acting on normal matter. For example, they can look at
Speaker 1: how fast stars cruise around a galaxy. When dark matter
Speaker 1: is present, that galaxy's gravity will be bulked up, causing
Speaker 1: its stars to move faster than if just normal matter
Speaker 1: were present. But in the case of n g C
Speaker 1: one oh five two dash DF two, an ultra diffuse
Speaker 1: galaxy located sixty five million light years away, astronomers have
Speaker 1: found that its stars are moving in exactly the way
Speaker 1: that would be predicted if only the total mass of
Speaker 1: all the visible stuff is considered. In other words, dark
Speaker 1: matter doesn't seem to be exerting its gravity on normal
Speaker 1: matter in that galaxy, and that's weird, Peter Van Dulkum
Speaker 1: of Yale University said in a statement, finding a galaxy
Speaker 1: without dark matter is unexpected because this invisible, mysterious substance
Speaker 1: is the most dominant aspect of any galaxy. For decades,
Speaker 1: we thought the galaxies start their lives as blobs of
Speaker 1: dark matter. After that everything else happens. Gas falls into
Speaker 1: the dark matter halo's the gas turns into stars. They
Speaker 1: slowly build up. Then you end up with galaxies like
Speaker 1: the Milky Way. This galaxy challenges the standard ideas of
Speaker 1: how we think galaxies form. Ultra diffuse galaxies are oddities
Speaker 1: in their own right, having only been discovered in as
Speaker 1: they are very difficult to detect. However, it appears that
Speaker 1: this class of galaxy is common, but none are like
Speaker 1: the one in question. The galaxy was discovered using the
Speaker 1: Dragonfly Telephoto Array, a telescope in New Mexico that's custom
Speaker 1: made to seek out these elusive targets. Then, using a
Speaker 1: set of twin ten meter optical and infrared telescopes in Hawaii,
Speaker 1: the astronomers signaled out ten bright globular clusters, which are large,
Speaker 1: compact groups of stars orbiting the galaxy's core. They then
Speaker 1: use spectral data to measure their motions. These clusters were
Speaker 1: found to be plotting along more slowly than expected, meaning
Speaker 1: there's far less mass in that galaxy then would be predicted.
Speaker 1: In fact, there's so little mass that the researchers have
Speaker 1: come to the astonishing conclusion that there's little, if any
Speaker 1: dark matter there. Follow Up observations were made with the
Speaker 1: Gemini North Telescope, also in Hawaii, so the galaxy structure
Speaker 1: could be studied. With Gemini's help. The researchers ruled out
Speaker 1: interactions with other galaxies as being the cause of its
Speaker 1: weird dark matter deficit, Ben Docom said in the press release,
Speaker 1: if there's any dark matter at all, it's very little.
Speaker 1: The stars in the galaxy can account for all of
Speaker 1: the mass, and there doesn't seem to be any room
Speaker 1: for dark matter. This finding seems to suggest the dark
Speaker 1: matter has quote its own separate existence apart from other
Speaker 1: components of galaxies. He added, and this makes the very
Speaker 1: existence of this galaxy and mystery. If it has no
Speaker 1: dark matter, how did even evolve into a galaxy. In
Speaker 1: their study published in March in the journal Nature, Ben
Speaker 1: Ducom's team speculates that some cataclysmic event in the galaxy
Speaker 1: may have cleared out all the dark matter and blasted
Speaker 1: away all the star forming gases. Alternatively, a nearby massive
Speaker 1: elliptical galaxy may have played a role in the current
Speaker 1: galaxies lack of dark matter billions of years ago when
Speaker 1: it was undergoing its early and violent stages of evolution. Now,
Speaker 1: the researchers are pouring over Hubble space telescopes observations of
Speaker 1: similar galaxies to perhaps find more that lack dark matter.
Speaker 1: If they find more, then altered, diffuse, and faint galaxies
Speaker 1: might be the norm when dark matter isn't press it,
Speaker 1: and that's a fascinating development in our understanding of how
Speaker 1: galaxies evolve. Ben Docom concluded, every galaxy we do about
Speaker 1: before has dark matter, and they all fall in familiar
Speaker 1: categories like spiral or elliptical galaxies. But what would you
Speaker 1: get if there was no dark matter at all? Maybe
Speaker 1: this is what you would get. Today's episode was written
Speaker 1: by dr Ian O'Neill and produced by Tyler Clang. Brain
Speaker 1: Stuff is a production of iHeart Radio's How Stuff Works.
Speaker 1: For more on this and lots of other dark topics,
Speaker 1: visit our home planet, how stuff Works dot com, and
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