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