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In billions of years, our Sun will expand to 300 times its current size, potentially engulfing Earth—what happens when a star becomes a red giant? And what about black holes? Scientists speculate on what lies beyond the event horizon. Explore these mind-bending cosmic phenomena and their future impacts on our universe!
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00:00A recent study has involved almost 200 huge stars that are reaching the end of their lives.
00:06It has given scientists more precise information about how the Sun will one day end.
00:12It turns out that the Sun will be about 200 to 300 times bigger than it is now by the
00:18time its game is over.
00:21For starters, let's begin with some basic information about star sizes.
00:26Giant ones reach this stage because they've run out of nuclear fuel and are no longer burning hydrogen in their
00:32core.
00:33Eventually, the core gets hot enough to trigger the next stage of fusion, which is helium burning.
00:39All the stars that were surveyed in this new study were either in this hydrogen shell burning or helium core
00:46burning phase.
00:48Even though giant and supergiant stars only make up less than 5% of all stars,
00:54or at least that we know of, they're actually really visible from a distance because they're so bright.
01:01In fact, according to scientists, about a third of all the stars you can see outside on a dark moonless
01:07night are giant or supergiant stars.
01:11This study will eventually give astronomers really useful info about massive stars.
01:17They'll be able to figure out their size and temperature no matter where they are or their evolutionary stage.
01:24This means they can see a star's true color and use that to find out its radius.
01:29Pretty cool, right?
01:31It does raise the question, what will our sun be like when it gets old and grumpy?
01:37To put it simply, it will expand when it starts burning its hydrogen shell,
01:41but then shrink a bit during its helium core burning phase.
01:45After a few hundred million years, it'll end up as a giant star, about 200 to 300 times its current
01:53size.
01:54Eventually, the sun will expand so much that it will simply evaporate.
01:59So, what will happen after the sun fades away?
02:03Scientists actually have some predictions about what will go down, even though we won't be around to see it.
02:09They're pretty sure the sun will turn into a planetary nebulae.
02:14These planetary nebulae are chunks of gas and dust in space that come from a star that is fading away.
02:21They got their name because they looked like planets to people using telescopes back in the 18th century,
02:28even though we now know they have nothing to do with actual planets.
02:32And here's the crazy thing.
02:35Astronomers have found out they can use the level of brightness of these planetary nebulae to calculate their distance from
02:41us.
02:42In 2018, scientists also found out that the sun is the smallest a star can be to still be able
02:49to produce a visible nebula.
02:51Any smaller, and it would not be visible.
02:54Stars that are up to three times more massive than the sun will produce brighter nebulae.
03:00The sun is currently 4.6 billion years old, but it's estimated to have another 10 billion years until its
03:08end.
03:09The sun is also getting brighter with each year.
03:13It doesn't seem like a lot now, but it's actually going to cause some big problems for Earth.
03:19In about a billion years, the sun will be too bright for life on Earth to survive.
03:24Our oceans will evaporate, and it will be too hot for water to form again.
03:30So unless we find a way to escape from this planet, humanity only has about a billion years left.
03:37Will Earth still be around by the time the sun turns to dust?
03:42It's hard to know for sure the exact timeline.
03:45But even before that happens, Earth will most likely be scorched and lifeless, with no atmosphere or oceans left.
03:52It's not clear how close the sun's outer layers will get to Earth.
03:57But if they get too close, it could cause Earth to spiral into the sun and disappear altogether.
04:05Even if our planet does somehow manage to survive the sun's giant phase, it will be orbiting a hot white
04:12dwarf, or a star that has run out of its fuel.
04:15In that distant future, the sun will be barely larger than our planet.
04:21Eventually, the sun will cool and dim completely.
04:24It'll move to another stage called a black dwarf.
04:27It will cause Earth's orbit to loosen up, and our planet will spiral into the faded sun.
04:33But interestingly, the sun doesn't get the final say in what happens to Earth.
04:39Gravity keeps planets in orbit, but it also attracts them to each other, which can cause their orbits to flex
04:45and drift.
04:46This could lead to the solar system destabilizing and ejecting planets, including Earth.
04:52Basically, a lot might happen in the next 5 billion years before the sun becomes a red giant.
04:59There's also another scenario.
05:02While most stars stay far away from our solar system, there's a chance that one could come closer in the
05:09next billion years.
05:10Even a small star or black hole could mess up the orbit of our planet if it gets too close.
05:17But don't worry too much.
05:18The odds of that happening are low because of the amount of space between stars.
05:24Our sun is a solitary star, so there's little to no chance we'll be able to catch a ride with
05:30another one nearby.
05:31However, many stars in our universe have companions.
05:35Among these stars is Castor, a stunning system that comprises six stars and is one of the brightest objects in
05:43the night sky.
05:45Although humans have been admiring Castor for ages, they were not aware of its true nature until the invention of
05:52telescopes and spectroscopes.
05:54Even with the help of a small telescope, it's evident that Castor is composed of two primary stars, Castor A
06:01and B A, that revolve around each other.
06:04These stars are larger than the sun and need 467 years to complete one orbit.
06:11In total, Castor is composed of six different stars.
06:15The biggest one, called Castor A A, is roughly two times larger than the sun, while the smallest has about
06:230.5 of the sun's mass.
06:26If humans want to survive the next billions of years, we might need to set up camp somewhere else in
06:32the universe.
06:33It may seem like something out of a sci-fi movie, but it could be our reality one day.
06:38Thankfully, NASA is already looking at some options.
06:42They've discovered two new planets, TOI-700E and TOI-700D.
06:49That might be new hotspots for us humans.
06:53TOI-700E is the optimistic zone, which means it could have water and even an atmosphere.
07:01TOI-700D is in the conservative habitable zone.
07:04So, scientists aren't too sure about it yet, but hey, we'll take what we can get.
07:10But hold on, before you start packing your bags, there's a little problem.
07:15How do we get there?
07:16It took John Glenn months of preparation just to circle Earth three times.
07:22So, we might need to start working on our astronaut training.
07:25Well, at least we have some options for our future intergalactic vacation plans.
07:31Wouldn't it be nice if we could time travel so we could see what our solar system will look like
07:36in billions of years?
07:37An American physicist named Ron Mallet has proposed one interesting theory for time travel.
07:43It uses light, a resource that is abundant in the universe.
07:48His idea involves using a rotating cylinder of light, which could transport an object in both space and time,
07:55similar to how a bubble moves in a swirling liquid.
07:59Mallet suggests that a cylinder of the right shape could allow for travel to the past and the future.
08:05To test his theory, he has been trying to secure funding for an experiment.
08:09However, some scientists consider Mallet's theory to be impossible and unnecessary to test.
08:16We might also be able to travel through time if we move fast enough.
08:21According to Einstein, the way we experience time can change depending on how fast we're moving.
08:26If we go really fast, time slows down.
08:29For example, astronauts in space age a tiny bit more slowly than people on Earth.
08:36This is important for things like GPS, which would be incorrect without special adjustments because of how time is affected.
08:43Black holes.
08:45An enigma that has puzzled scientists and captivated our imagination for decades.
08:50But what's hiding inside of a black hole?
08:53Is it a void?
08:54A bottomless pit?
08:56A parallel universe?
08:57We don't know for sure yet.
08:59But scientists might have some ideas.
09:02So let's hear them out.
09:05Picture this.
09:06In the vastness of space, there's a supermassive star shining bright like a diamond.
09:12But like all good things, this star's party can't last forever.
09:16Eventually, it runs out of fuel and goes out with a bang.
09:21Quite literally.
09:21The star collapses under its own gravity, creating an implosion.
09:28Now, this collapse is so intense that it creates a bottomless pit in space, like a sinkhole.
09:35This is what we call a black hole.
09:38The ultimate no-escape zone.
09:40Sucking up everything in its vicinity, including light.
09:46Imagine yourself approaching a black hole.
09:49The black hole itself doesn't emit any light.
09:51But you can notice a dazzling display of cosmic fireworks surrounding it.
09:56The accretion disk.
09:58It's like a celestial carousel of gas and dust, swirling in a mesmerizing dance around the black hole.
10:05The incredible gravitational forces pull all this material from their surroundings, creating this celestial furnace.
10:14Of course, it's very unlikely that you would have survived in this place.
10:19Temperatures here soar to millions of degrees.
10:23Also, it's constantly dazzling x-rays and high-energy radiation that can be detected from telescopes on Earth.
10:32But let's imagine that you did survive, somehow.
10:36As you get closer, you notice a mysterious boundary looming ahead.
10:40The event horizon.
10:42It's a point of no return, beyond which the laws of physics seem to go haywire.
10:47Now you're stuck in a space traffic jam.
10:50And no matter how hard you hit the gas, you're going nowhere.
10:54Once you cross this threshold, not even light can escape.
11:00And now, you inevitably fall into a black hole.
11:04What do you see around you?
11:08According to the genius physicist Albert Einstein, space and time aren't separate entities, but rather intertwined in a fabric called
11:17space-time.
11:18It's like a cosmic trampoline that can stretch and bend if you place something heavy on it.
11:23And black holes are super heavy, which is why they distort this trampoline in the most extreme way possible.
11:33So, when you venture close to a black hole, you're in for a roller coaster ride.
11:38The curvature of space-time becomes so intense that it's like a whirlpool pulling everything in, even light itself.
11:46Everything around you looks like a space funhouse with distorted colors and rays of light that keep shifting.
11:52All this makes you feel like you're doing the moonwalk on a treadmill.
11:58Also, the curvature of space-time around a black hole is so extreme that it creates a phenomenon called time
12:06dilation.
12:07Time near a black hole moves at a different pace than in the rest of the universe.
12:12The closer you are to the black hole, the slower time ticks, like a slow-motion effect.
12:20And the deeper you fall, the weirder things get.
12:24The laws of physics seem to break down before your very eyes.
12:27But suppose you somehow manage to survive all this madness.
12:31Where exactly are you falling?
12:34What awaits you on the other side?
12:36Is there even an other side?
12:40As you venture deeper into the celestial maelstrom, you reach an elusive and mysterious point called the singularity.
12:49It's the heart of a black hole, a place where all matter and energy are crushed into a single, unimaginably
12:57dense point.
12:58Imagine cramming masses of entire stars to something that is essentially a pinprick.
13:05And now that you're here, forget about the usual rules of physics.
13:10Welcome to a new realm, where the known breaks down and the unknown takes over.
13:18So, what does this unknown look like?
13:21Well, there are a couple of theories.
13:25First off, it could be a gateway to other dimensions.
13:29What if there are multiple universes hiding within black holes, like nesting dolls?
13:34According to this theory, the interior of a black hole could be a portal to a parallel universe,
13:40with its own set of physical laws and possibilities.
13:44This parallel universe could be drastically different from our own world.
13:48What a mind-bending idea!
13:52Or what about wormholes?
13:54Imagine black holes forming a space subway system,
13:59connecting different regions of space and time with each other.
14:03These theories suggest that the extreme gravitational pull of a black hole could create a wormhole,
14:09a tunnel that could transport you to another galaxy,
14:13or even to the past or future.
14:16It's like finding a secret passage in a video game.
14:21That's not all.
14:23Some scientists propose that inside a black hole, we might find some exotic matter.
14:28Some strange matter with weird properties or negative energy density.
14:33If that's the case, this would defy our understanding of the universe.
14:39And finally, one of the most mind-bending theories is that a black hole could actually lead to a white
14:46hole.
14:49Imagine, as you fall further, you suddenly find yourself in a blindingly bright space show.
14:55You're in a white hole.
14:57This is a fountain that's spewing out matter, energy, and information into the universe with reckless abandon.
15:08You see, while black holes are known for their event horizon, white holes have an anti-event horizon.
15:16With black holes, everything can enter and nothing can come out.
15:20With white holes, it's the other way around.
15:23They repel everything.
15:27White holes are hypothetical objects.
15:29Their existence hasn't yet been proven.
15:32But if it turns out that they exist, they could be connected to black holes.
15:36It makes sense.
15:38Black holes suck everything in.
15:40And white holes should take their matter from somewhere.
15:44And all this matter and energy coming out of the white hole could potentially form new universes.
15:50Together with black holes, they could form a universal cycle of creation.
15:55The end of one universe leads to the birth of another.
16:01All these theories are beautiful and fascinating.
16:04But here's the catch.
16:06There's still no concrete evidence of any of them.
16:12Black holes still remain one of the biggest mysteries of our world.
16:16Unfortunately, studying these mysterious beasts isn't easy.
16:21They're super elusive.
16:23And this is one of the biggest challenges for scientists.
16:26Black holes don't emit light.
16:28So they can't be seen directly.
16:31They're essentially invisible to telescopes that rely on light.
16:34Making them incredibly difficult to observe.
16:37That's why scientists have to rely on things like X-ray emissions.
16:40The effects of a black hole's gravity on nearby objects.
16:45And other clues.
16:47They're also very unpredictable.
16:50For black holes, physics is like a fun playground.
16:54They warp space and time around them.
16:57Which makes it difficult to predict and understand their behavior.
17:02But don't worry, space enthusiasts.
17:05The future of research in this field is as promising as ever.
17:08We've already made incredible discoveries.
17:11For example, in 2019, we captured the first ever direct image of a black hole.
17:17This is a central black hole of the galaxy Messier 87.
17:21A few years later, we also took a photo of a black hole in the center of our own galaxy,
17:27the Milky Way.
17:28This one is called Sagittarius A-star.
17:31All this has opened up new avenues for research.
17:36And these aren't the only cool things we've discovered in recent years.
17:40Let's take gravitational waves, for example.
17:43You know how rocks leave ripples after falling into water?
17:47Well, gravitational waves are ripples in a fabric of space-time.
17:52They carry clues about the most cataclysmic events in the universe.
17:56They've allowed us to listen to the universe, unveiling previously hidden phenomena and events.
18:02And all these observations provide us with a new way to study black holes.
18:09We constantly make new advancements in technology.
18:13The James Webb Space Telescope will provide us with even more detailed observations and insights into the mysteries of black
18:21holes.
18:23There's still so much we don't know.
18:26But that's the beauty of science, the thrill of the unknown, and the curiosity that drives us to explore the
18:32mysteries of the universe.
18:35So, let's keep peering into the cosmic abyss on the thrilling quest to unlock the secrets of our world.
18:41See you all later.
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