WEBVTT

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<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos

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<v Speaker 1>with our soothing Bedtime Astronomy podcast. Each episode offers a

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<v Speaker 1>gentle journey through the stars, planets, and beyond, perfect for

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<v Speaker 1>unwinding after a long day. Let's travel through the mysteries

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<v Speaker 1>of the universe as you drift off into a peaceful

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<v Speaker 1>slumber under the night sky. This week in Astronomy, dark matter,

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<v Speaker 1>biggest black hole merger, and Hidden Galaxies dark dwarfs. A

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<v Speaker 1>new clue to what dark matter is. Dark matter is

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<v Speaker 1>something scientists know is real, but they still don't know

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<v Speaker 1>exactly what it is. It doesn't glow, reflect light, or

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<v Speaker 1>interact with normal matter in any obvious way, but they

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<v Speaker 1>know it's there because it holds galaxies together with its gravity,

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<v Speaker 1>otherwise galaxies would fall apart. Scientists think dark matter might

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<v Speaker 1>only interact with itself, not with regular matter like us.

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<v Speaker 1>If that's true, dark matter particles could crash into each

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<v Speaker 1>other and destroy themselves. This destruction would release energy, but

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<v Speaker 1>for that to happen, dark matter has to be packed

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<v Speaker 1>tightly in one place. A new idea from researchers suggests

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<v Speaker 1>that this might happen inside a special kind of object

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<v Speaker 1>called the brown dwarf. Brown dwarfs are bigger than planets,

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<v Speaker 1>but not big enough to shine like stars. When they form,

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<v Speaker 1>they start like stars, but they don't get enough gas

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<v Speaker 1>to begin the nuclear reactions that power real stars, so

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<v Speaker 1>they stay dim and cool for the rest of their lives.

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<v Speaker 1>Because brown dwarfs are so faint and small, they are

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<v Speaker 1>hard to find. But if dark matter is inside them

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<v Speaker 1>and starts to destroy itself, that process could release energy

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<v Speaker 1>and heat the brown dwarf up. That extra heat could

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<v Speaker 1>make them easier to detect, so instead of just brown

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<v Speaker 1>dwarf dwarfs, we might be able to find dark dwarfs,

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<v Speaker 1>brown dwarfs powered by dark matter. This idea was explored

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<v Speaker 1>by a group of scientists led by Jenna Krohne, who

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<v Speaker 1>works at Durham University. Her teen believes these dark dwarfs

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<v Speaker 1>might exist near the center of our galaxy. That's because

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<v Speaker 1>there's more dark matter in that area, making it more

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<v Speaker 1>likely that brown dwarfs there could gather enough dark matter

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<v Speaker 1>to start the self destruction process. The key to spotting

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<v Speaker 1>these dark dwarfs might be a form of lithium called

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<v Speaker 1>lithium seven. Normal brown dwarfs use up their lithium seven

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<v Speaker 1>early in life, but dark dwarfs wouldn't burn theirs because

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<v Speaker 1>the energy would be coming from dark matter, not fusion.

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<v Speaker 1>So if astronomers find a star like object with lots

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<v Speaker 1>of lithium but more mass than a normal brown dwarf,

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<v Speaker 1>it could be a sign that it's a dark dwarf.

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<v Speaker 1>These dark dwarfs would be a little heavier than brown

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<v Speaker 1>dwarfs and would stay the same brightness in temperature over time.

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<v Speaker 1>They would also keep their lithium while regular brown dwarfs

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<v Speaker 1>would lose it. That makes lithium a kind of marker

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<v Speaker 1>scientists can use to tell the difference. Detecting dark dwarfs

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<v Speaker 1>would be a big deal. It would help scientists figure

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<v Speaker 1>out what dark matter is made of. One strong possibility

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<v Speaker 1>is something called whimps, short for weekly interacting massive particles.

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<v Speaker 1>This theory only works if dark matter is made of

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<v Speaker 1>these whimps or something very similar that can destroy itself

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<v Speaker 1>and release energy. Finding dark dwarfs wouldn't prove dark matter

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<v Speaker 1>as whimps for sure, but it would be a strong clue,

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<v Speaker 1>and even if whimps aren't the answer, discovering dark dwarfs

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<v Speaker 1>would show that dark matter is made of something heavy

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<v Speaker 1>that interacts with itself in a special way, something we

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<v Speaker 1>haven't seen before. Even though these dark dwarfs are very

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<v Speaker 1>cold and hard to find, scientists think telescopes like the

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<v Speaker 1>James Webb Space Telescope might be able to see them,

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<v Speaker 1>or they could study lots of starlike objects and look

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<v Speaker 1>for patterns that suggest a group of them might be

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<v Speaker 1>dark dwarfs. If even one dark dwarf is found, it

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<v Speaker 1>would bring us much closer to understanding dark matter. One

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<v Speaker 1>of the biggest mysteries in science today biggest black hole

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<v Speaker 1>merger ever detected. Scientists working with the LIGO, Virgo and

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<v Speaker 1>Kagra observatories recently made a major discovery. They found the

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<v Speaker 1>biggest black hole merger ever seen through gravitational waves. This

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<v Speaker 1>happened on November twenty third, twenty twenty three, and the

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<v Speaker 1>new black hole that formed from the event is about

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<v Speaker 1>two hundred and twenty five times heavier than our sun.

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<v Speaker 1>The signal from this event was given the name GW

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<v Speaker 1>two three one one two three LIGO, which stands for

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<v Speaker 1>Laser Interferometer Gravitational Wave Observatory. First made headlines in twenty

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<v Speaker 1>fifteen when it detected gravitational waves for the very very

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<v Speaker 1>first time. Gravitational waves are tiny ripples in the fabric

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<v Speaker 1>of space and time caused by powerful cosmic events like

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<v Speaker 1>two black holes crashing into each other. That first detection

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<v Speaker 1>came from a merger that created a black hole about

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<v Speaker 1>sixty two times the Sun's mass. Since then, LIGO joined

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<v Speaker 1>forces with two other detectors, Virgo and Italy and Cagar

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<v Speaker 1>and Japan. Together they form a global team known as

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<v Speaker 1>the LVK Collaboration. Over the years, they've detected around three

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<v Speaker 1>hundred black hole mergers, including more than two hundred just

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<v Speaker 1>in their latest round of observations. Before this latest event,

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<v Speaker 1>the biggest black hole formed through a merger was seen

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<v Speaker 1>in twenty twenty one and was about one hundred and

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<v Speaker 1>forty times the mass of the Sun. But this new

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<v Speaker 1>discovery is even more massive. It was created when two

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<v Speaker 1>very large black holes, one around one hundred times the

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<v Speaker 1>Sun's mass and the other about one hundred and forty times,

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<v Speaker 1>merged into one. Besides being extremely heavy, these black holes

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<v Speaker 1>are also spinning very fast. In fact, they might be

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<v Speaker 1>spinning as fast as the laws of physics allow. Based

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<v Speaker 1>on Einstein's theory of general relativity. That makes this event

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<v Speaker 1>especially hard to study, because the faster the black holes spin,

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<v Speaker 1>the more complex their behavior becomes. Scientists had to use

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<v Speaker 1>advanced computer models to try to understand what happened. This

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<v Speaker 1>discovery is important because, according to current theories, black holes

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<v Speaker 1>this large shouldn't be able to form in the usual

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<v Speaker 1>way from dying stars. Some scientists think these two black

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<v Speaker 1>holes might have already formed from earlier black hole mergers.

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<v Speaker 1>That means we might be seeing black holes made from

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<v Speaker 1>a chain of mergers over time. This kind of observation

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<v Speaker 1>is helping researchers learn more about how black holes form

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<v Speaker 1>and behave. It's also pushing the limits of what current

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<v Speaker 1>technology and scientific models can handle. Experts believe it will

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<v Speaker 1>take years to fully understand all the details of this

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<v Speaker 1>particular event. It's possible that the data from this detection

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<v Speaker 1>could even reveal new ideas about black holes that scientists

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<v Speaker 1>haven't considered yet. The Ligo, Virgo and Caagri detectors are

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<v Speaker 1>tools that measure incredibly tiny changes in space caused by

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<v Speaker 1>events like this. They started their fourth round of observations

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<v Speaker 1>in May twenty twenty three and are still gathering more data.

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<v Speaker 1>Results from the first part of this observation period are

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<v Speaker 1>expected to be shared later in the year. The new

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<v Speaker 1>black hole merger GW two three one one two three

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<v Speaker 1>will be discussed at a major science conference happening in

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<v Speaker 1>July twenty twenty five in Glasgow, Scotland. The data from

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<v Speaker 1>this event will also be made public so other scientists

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<v Speaker 1>around the world can study it too. This discovery is

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<v Speaker 1>not just about one big black hole. It's about opening

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<v Speaker 1>a window into the hidden parts of the universe and

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<v Speaker 1>learning how much more is out there waiting to be understood.

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<v Speaker 1>Hidden galaxies may be orbiting the Milky Way. Scientists at

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<v Speaker 1>Durham University believe there are many more tiny galaxies orbiting

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<v Speaker 1>the Milky Way than we've seen so far. They use

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<v Speaker 1>supercomputers in advanced math to look deeper into this mystery.

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<v Speaker 1>Their research suggests there could be eighty to one hundred

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<v Speaker 1>extra satellite galaxies around our own, much more than the

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<v Speaker 1>sixty we already know about. These galaxies are incredibly faint

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<v Speaker 1>and difficult to see. Some of them are so stripped

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<v Speaker 1>of their material, especially the dark matter that usually surrounds galaxies,

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<v Speaker 1>that they've become almost invisible. Because of that, they don't

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<v Speaker 1>show up in most computer simulations. That's why the researchers

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<v Speaker 1>call them morphin galaxies. They've lost the big dark matter

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<v Speaker 1>halos they were born in, possibly pulled apart by the

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<v Speaker 1>Milky Way's own gravity over billions of years, but the

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<v Speaker 1>scientists think these orphans are still out there in real life,

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<v Speaker 1>just hidden from our view. Their work supports a major

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<v Speaker 1>theory about how the universe works, called the Land of

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<v Speaker 1>Cold dark Matter model, or LCEDM. This model says most

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<v Speaker 1>of the universe is made up of things we can't see.

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<v Speaker 1>Only about five percent is made of atoms, like the

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<v Speaker 1>ones that make up people, planets, and stars. About twenty

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<v Speaker 1>five percent is dark matter, which we can't see but

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<v Speaker 1>know is there because of how it pulls on things,

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<v Speaker 1>and the rest about seventy percent is something even more

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<v Speaker 1>mysterious called dark energy. According to this theory, galaxies like

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<v Speaker 1>ours form inside huge clumps of dark matter, and most

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<v Speaker 1>galaxies are small and orbit around bigger ones like the

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<v Speaker 1>Milky Way. For a long time, scientists have noticed something odd.

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<v Speaker 1>According to LCDM, there should be way more of these

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<v Speaker 1>small satellite galaxies than we've actually seen. That mismatch has

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<v Speaker 1>been a problem for the theory, but the new study

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<v Speaker 1>shows that we may have been missing the faintest and

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<v Speaker 1>smallest ones simply because they're hard to detect with today's technology.

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<v Speaker 1>They've been around for billions of years, but are so

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<v Speaker 1>dim they've slipped past our instruments. The Durham researchers used

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<v Speaker 1>some of the best tools available to study this. One

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<v Speaker 1>is a powerful computer simulation called Aquarius, which shows what

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<v Speaker 1>dark matter around the Milky Way might look like in

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<v Speaker 1>high detail. The other is a tool called Galform developed

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<v Speaker 1>at Durham, which follows how galaxies form and change over time.

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<v Speaker 1>By combining the two, they could better understand where these

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<v Speaker 1>faint galaxies might be hiding. Their work shows that many

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<v Speaker 1>small galaxies likely got pulled close to the Milky Way

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<v Speaker 1>long ago. Over time, gravity stripped away their dark matter

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<v Speaker 1>and stars, leaving behind these ghostlike galaxies. But they're still there,

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<v Speaker 1>and if we build better telescopes or use smarter methods

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<v Speaker 1>to look, we might finally spot them. Some of these

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<v Speaker 1>predicted galaxies may already have been seen. In recent years,

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<v Speaker 1>astronomers have found about thirty tiny objects that might be

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<v Speaker 1>satellite galaxies, but it's not clear what they are They

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<v Speaker 1>could be dwarf galaxies with some dark matter left, or

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<v Speaker 1>just dense star clusters. The researchers think these new objects

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<v Speaker 1>might be part of the missing group they predicted. This

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<v Speaker 1>study is exciting because it might help solve a long

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<v Speaker 1>standing puzzle in our understanding of the universe. If telescopes

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<v Speaker 1>like the Reuben Observatory, which recently started operating, find these

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<v Speaker 1>hidden galaxies, it would be a big win for the

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<v Speaker 1>LCDM theory. It would show that with the right combination

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<v Speaker 1>of physics, math, and computing power, we can make bold

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<v Speaker 1>predictions about things we can't even see yet and then

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<v Speaker 1>go out and find them. M bad a