This Week in Astronomy: Dark Matter, Biggest Black Hole Merger and Hidden Galaxies

<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
<v Speaker 1>with our soothing Bedtime Astronomy podcast. Each episode offers a
<v Speaker 1>gentle journey through the stars, planets, and beyond, perfect for
<v Speaker 1>unwinding after a long day. Let's travel through the mysteries
<v Speaker 1>of the universe as you drift off into a peaceful
<v Speaker 1>slumber under the night sky. This week in Astronomy, dark matter,
<v Speaker 1>biggest black hole merger, and Hidden Galaxies dark dwarfs. A
<v Speaker 1>new clue to what dark matter is. Dark matter is
<v Speaker 1>something scientists know is real, but they still don't know
<v Speaker 1>exactly what it is. It doesn't glow, reflect light, or
<v Speaker 1>interact with normal matter in any obvious way, but they
<v Speaker 1>know it's there because it holds galaxies together with its gravity,
<v Speaker 1>otherwise galaxies would fall apart. Scientists think dark matter might
<v Speaker 1>only interact with itself, not with regular matter like us.
<v Speaker 1>If that's true, dark matter particles could crash into each
<v Speaker 1>other and destroy themselves. This destruction would release energy, but
<v Speaker 1>for that to happen, dark matter has to be packed
<v Speaker 1>tightly in one place. A new idea from researchers suggests
<v Speaker 1>that this might happen inside a special kind of object
<v Speaker 1>called the brown dwarf. Brown dwarfs are bigger than planets,
<v Speaker 1>but not big enough to shine like stars. When they form,
<v Speaker 1>they start like stars, but they don't get enough gas
<v Speaker 1>to begin the nuclear reactions that power real stars, so
<v Speaker 1>they stay dim and cool for the rest of their lives.
<v Speaker 1>Because brown dwarfs are so faint and small, they are
<v Speaker 1>hard to find. But if dark matter is inside them
<v Speaker 1>and starts to destroy itself, that process could release energy
<v Speaker 1>and heat the brown dwarf up. That extra heat could
<v Speaker 1>make them easier to detect, so instead of just brown
<v Speaker 1>dwarf dwarfs, we might be able to find dark dwarfs,
<v Speaker 1>brown dwarfs powered by dark matter. This idea was explored
<v Speaker 1>by a group of scientists led by Jenna Krohne, who
<v Speaker 1>works at Durham University. Her teen believes these dark dwarfs
<v Speaker 1>might exist near the center of our galaxy. That's because
<v Speaker 1>there's more dark matter in that area, making it more
<v Speaker 1>likely that brown dwarfs there could gather enough dark matter
<v Speaker 1>to start the self destruction process. The key to spotting
<v Speaker 1>these dark dwarfs might be a form of lithium called
<v Speaker 1>lithium seven. Normal brown dwarfs use up their lithium seven
<v Speaker 1>early in life, but dark dwarfs wouldn't burn theirs because
<v Speaker 1>the energy would be coming from dark matter, not fusion.
<v Speaker 1>So if astronomers find a star like object with lots
<v Speaker 1>of lithium but more mass than a normal brown dwarf,
<v Speaker 1>it could be a sign that it's a dark dwarf.
<v Speaker 1>These dark dwarfs would be a little heavier than brown
<v Speaker 1>dwarfs and would stay the same brightness in temperature over time.
<v Speaker 1>They would also keep their lithium while regular brown dwarfs
<v Speaker 1>would lose it. That makes lithium a kind of marker
<v Speaker 1>scientists can use to tell the difference. Detecting dark dwarfs
<v Speaker 1>would be a big deal. It would help scientists figure
<v Speaker 1>out what dark matter is made of. One strong possibility
<v Speaker 1>is something called whimps, short for weekly interacting massive particles.
<v Speaker 1>This theory only works if dark matter is made of
<v Speaker 1>these whimps or something very similar that can destroy itself
<v Speaker 1>and release energy. Finding dark dwarfs wouldn't prove dark matter
<v Speaker 1>as whimps for sure, but it would be a strong clue,
<v Speaker 1>and even if whimps aren't the answer, discovering dark dwarfs
<v Speaker 1>would show that dark matter is made of something heavy
<v Speaker 1>that interacts with itself in a special way, something we
<v Speaker 1>haven't seen before. Even though these dark dwarfs are very
<v Speaker 1>cold and hard to find, scientists think telescopes like the
<v Speaker 1>James Webb Space Telescope might be able to see them,
<v Speaker 1>or they could study lots of starlike objects and look
<v Speaker 1>for patterns that suggest a group of them might be
<v Speaker 1>dark dwarfs. If even one dark dwarf is found, it
<v Speaker 1>would bring us much closer to understanding dark matter. One
<v Speaker 1>of the biggest mysteries in science today biggest black hole
<v Speaker 1>merger ever detected. Scientists working with the LIGO, Virgo and
<v Speaker 1>Kagra observatories recently made a major discovery. They found the
<v Speaker 1>biggest black hole merger ever seen through gravitational waves. This
<v Speaker 1>happened on November twenty third, twenty twenty three, and the
<v Speaker 1>new black hole that formed from the event is about
<v Speaker 1>two hundred and twenty five times heavier than our sun.
<v Speaker 1>The signal from this event was given the name GW
<v Speaker 1>two three one one two three LIGO, which stands for
<v Speaker 1>Laser Interferometer Gravitational Wave Observatory. First made headlines in twenty
<v Speaker 1>fifteen when it detected gravitational waves for the very very
<v Speaker 1>first time. Gravitational waves are tiny ripples in the fabric
<v Speaker 1>of space and time caused by powerful cosmic events like
<v Speaker 1>two black holes crashing into each other. That first detection
<v Speaker 1>came from a merger that created a black hole about
<v Speaker 1>sixty two times the Sun's mass. Since then, LIGO joined
<v Speaker 1>forces with two other detectors, Virgo and Italy and Cagar
<v Speaker 1>and Japan. Together they form a global team known as
<v Speaker 1>the LVK Collaboration. Over the years, they've detected around three
<v Speaker 1>hundred black hole mergers, including more than two hundred just
<v Speaker 1>in their latest round of observations. Before this latest event,
<v Speaker 1>the biggest black hole formed through a merger was seen
<v Speaker 1>in twenty twenty one and was about one hundred and
<v Speaker 1>forty times the mass of the Sun. But this new
<v Speaker 1>discovery is even more massive. It was created when two
<v Speaker 1>very large black holes, one around one hundred times the
<v Speaker 1>Sun's mass and the other about one hundred and forty times,
<v Speaker 1>merged into one. Besides being extremely heavy, these black holes
<v Speaker 1>are also spinning very fast. In fact, they might be
<v Speaker 1>spinning as fast as the laws of physics allow. Based
<v Speaker 1>on Einstein's theory of general relativity. That makes this event
<v Speaker 1>especially hard to study, because the faster the black holes spin,
<v Speaker 1>the more complex their behavior becomes. Scientists had to use
<v Speaker 1>advanced computer models to try to understand what happened. This
<v Speaker 1>discovery is important because, according to current theories, black holes
<v Speaker 1>this large shouldn't be able to form in the usual
<v Speaker 1>way from dying stars. Some scientists think these two black
<v Speaker 1>holes might have already formed from earlier black hole mergers.
<v Speaker 1>That means we might be seeing black holes made from
<v Speaker 1>a chain of mergers over time. This kind of observation
<v Speaker 1>is helping researchers learn more about how black holes form
<v Speaker 1>and behave. It's also pushing the limits of what current
<v Speaker 1>technology and scientific models can handle. Experts believe it will
<v Speaker 1>take years to fully understand all the details of this
<v Speaker 1>particular event. It's possible that the data from this detection
<v Speaker 1>could even reveal new ideas about black holes that scientists
<v Speaker 1>haven't considered yet. The Ligo, Virgo and Caagri detectors are
<v Speaker 1>tools that measure incredibly tiny changes in space caused by
<v Speaker 1>events like this. They started their fourth round of observations
<v Speaker 1>in May twenty twenty three and are still gathering more data.
<v Speaker 1>Results from the first part of this observation period are
<v Speaker 1>expected to be shared later in the year. The new
<v Speaker 1>black hole merger GW two three one one two three
<v Speaker 1>will be discussed at a major science conference happening in
<v Speaker 1>July twenty twenty five in Glasgow, Scotland. The data from
<v Speaker 1>this event will also be made public so other scientists
<v Speaker 1>around the world can study it too. This discovery is
<v Speaker 1>not just about one big black hole. It's about opening
<v Speaker 1>a window into the hidden parts of the universe and
<v Speaker 1>learning how much more is out there waiting to be understood.
<v Speaker 1>Hidden galaxies may be orbiting the Milky Way. Scientists at
<v Speaker 1>Durham University believe there are many more tiny galaxies orbiting
<v Speaker 1>the Milky Way than we've seen so far. They use
<v Speaker 1>supercomputers in advanced math to look deeper into this mystery.
<v Speaker 1>Their research suggests there could be eighty to one hundred
<v Speaker 1>extra satellite galaxies around our own, much more than the
<v Speaker 1>sixty we already know about. These galaxies are incredibly faint
<v Speaker 1>and difficult to see. Some of them are so stripped
<v Speaker 1>of their material, especially the dark matter that usually surrounds galaxies,
<v Speaker 1>that they've become almost invisible. Because of that, they don't
<v Speaker 1>show up in most computer simulations. That's why the researchers
<v Speaker 1>call them morphin galaxies. They've lost the big dark matter
<v Speaker 1>halos they were born in, possibly pulled apart by the
<v Speaker 1>Milky Way's own gravity over billions of years, but the
<v Speaker 1>scientists think these orphans are still out there in real life,
<v Speaker 1>just hidden from our view. Their work supports a major
<v Speaker 1>theory about how the universe works, called the Land of
<v Speaker 1>Cold dark Matter model, or LCEDM. This model says most
<v Speaker 1>of the universe is made up of things we can't see.
<v Speaker 1>Only about five percent is made of atoms, like the
<v Speaker 1>ones that make up people, planets, and stars. About twenty
<v Speaker 1>five percent is dark matter, which we can't see but
<v Speaker 1>know is there because of how it pulls on things,
<v Speaker 1>and the rest about seventy percent is something even more
<v Speaker 1>mysterious called dark energy. According to this theory, galaxies like
<v Speaker 1>ours form inside huge clumps of dark matter, and most
<v Speaker 1>galaxies are small and orbit around bigger ones like the
<v Speaker 1>Milky Way. For a long time, scientists have noticed something odd.
<v Speaker 1>According to LCDM, there should be way more of these
<v Speaker 1>small satellite galaxies than we've actually seen. That mismatch has
<v Speaker 1>been a problem for the theory, but the new study
<v Speaker 1>shows that we may have been missing the faintest and
<v Speaker 1>smallest ones simply because they're hard to detect with today's technology.
<v Speaker 1>They've been around for billions of years, but are so
<v Speaker 1>dim they've slipped past our instruments. The Durham researchers used
<v Speaker 1>some of the best tools available to study this. One
<v Speaker 1>is a powerful computer simulation called Aquarius, which shows what
<v Speaker 1>dark matter around the Milky Way might look like in
<v Speaker 1>high detail. The other is a tool called Galform developed
<v Speaker 1>at Durham, which follows how galaxies form and change over time.
<v Speaker 1>By combining the two, they could better understand where these
<v Speaker 1>faint galaxies might be hiding. Their work shows that many
<v Speaker 1>small galaxies likely got pulled close to the Milky Way
<v Speaker 1>long ago. Over time, gravity stripped away their dark matter
<v Speaker 1>and stars, leaving behind these ghostlike galaxies. But they're still there,
<v Speaker 1>and if we build better telescopes or use smarter methods
<v Speaker 1>to look, we might finally spot them. Some of these
<v Speaker 1>predicted galaxies may already have been seen. In recent years,
<v Speaker 1>astronomers have found about thirty tiny objects that might be
<v Speaker 1>satellite galaxies, but it's not clear what they are They
<v Speaker 1>could be dwarf galaxies with some dark matter left, or
<v Speaker 1>just dense star clusters. The researchers think these new objects
<v Speaker 1>might be part of the missing group they predicted. This
<v Speaker 1>study is exciting because it might help solve a long
<v Speaker 1>standing puzzle in our understanding of the universe. If telescopes
<v Speaker 1>like the Reuben Observatory, which recently started operating, find these
<v Speaker 1>hidden galaxies, it would be a big win for the
<v Speaker 1>LCDM theory. It would show that with the right combination
<v Speaker 1>of physics, math, and computing power, we can make bold
<v Speaker 1>predictions about things we can't even see yet and then
<v Speaker 1>go out and find them. M bad a