- 1 week ago
For years, scientists have searched for a world with the right combination of size, temperature, and atmosphere to reveal whether Earth is truly unique. Now, the James Webb Space Telescope may have found the planet they have been waiting for—one carrying clues that could transform our understanding of life beyond the Solar System. But what Webb detected in its atmosphere may be even more important than the planet itself.
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00:00An exoplanet is any planet inside our solar system.
00:04Some of them are free-floating.
00:05Those are called rogue planets.
00:07They move around the galactic center.
00:09Others orbit their host star, or two.
00:12For the first time, astronomers discovered exoplanets in the 1990s.
00:17Since then, scientists have found thousands of them.
00:20And now, you can sneak a peek too.
00:22Spoiler alert, some exoplanets are pretty bizarre.
00:26Other resemble our home planet and could probably support life.
00:30The closest to Earth exoplanet is Proxima Centauri b.
00:35It's a mere 4.2 light-years away from Earth.
00:38Recently, astronomers have found out that this world might resemble Earth even more than previously thought.
00:44It's only 17% more massive than our home planet.
00:48It orbits a star that is dimmer and less massive than the Sun.
00:51Proxima Centauri b is in the middle of the star's habitable zone.
00:56This means that chances are, liquid water and life might exist on the planet.
01:02It looks like the exoplanet is tidally locked with its parent star.
01:07This means one of its sides faces the star at all times, and the other is always in the darkness.
01:13Scientists haven't figured out yet whether the planet has an atmosphere.
01:18It's traveling too close to its star and completes one orbit within 11 Earth days.
01:23The radiation from the star might be pulling the planet's air away.
01:27If this is the case, Proxima Centauri b isn't likely to have liquid water on its surface.
01:35Gliese 832 c is 16 light-years away from Earth.
01:39In the cosmic scheme of things, it's a stone's throw away.
01:42This exoplanet is five times as massive as Earth and travels much closer to its parent star.
01:48That's why a year on this planet lasts a mere 36 days.
01:52But since this star is a red dwarf, much cooler and dimmer than the Sun,
01:57Gliese 832 c gets as much light and heat as our planet does.
02:03At the same time, it's still unclear if Gliese 832 c is similar to Earth.
02:08It probably has a much thicker atmosphere that creates a runaway greenhouse effect.
02:13This phenomenon occurs when a planet absorbs more heat from its host star
02:17than it can release back into space.
02:20This means that Gliese 832 c is more likely to resemble scorching hot Venus
02:26rather than relatively cool Earth.
02:29Another Earth-like planet, TOI-700d, is 100 light-years away from us in the constellation Dorado.
02:37It orbits a small and rather cool dwarf star that is about 40% of the mass and size of
02:44the Sun.
02:45Its surface temperature is half as high as that of our star.
02:49The outermost planet, which is the very TOI-700d, is almost the size of Earth.
02:55It also sits in the habitable zone of its parent star.
02:58No flares from TOI-700 reach the planet.
03:02This increases the chances of the exoplanet being habitable.
03:05This means it can potentially develop and maintain life.
03:11Scientists don't know for sure the exact conditions on the surface of the planet.
03:15But one of the computer simulations they've created shows a planet covered with an ocean.
03:20It has a very dense atmosphere dominated by carbon dioxide.
03:25Astronomers think a similar atmosphere surrounded Mars when it was a young planet.
03:29But another 3D model shows TOI-700d as an all-land cloudless world.
03:35That's what our Earth would probably look like if it wasn't covered with oceans.
03:40Winds on TOI-700d move away from the night side of the planet and meet in the area that directly
03:47faces the star.
03:49There is an exoplanet that stands out among the rest because of its awesome magenta color.
03:55You can find this world in the Virgo constellation.
03:59The planet is called Gliese 504b.
04:02The distance between this planet and its parent star is 9 times the distance between the Sun and Jupiter.
04:09The planet formed relatively recently and is still glowing with heat.
04:14That's why its surface looks pinkish.
04:18Just 20 light-years away from the Sun, which isn't such a great distance when we talk about space,
04:23a bizarre rogue planet is roaming our home Milky Way galaxy.
04:27But even though this planet doesn't orbit any star, it still has an incredibly powerful magnetic field.
04:33It's 4 million times stronger than Earth's magnetic field.
04:37The exoplanet also produces amazing auroras.
04:41When it was discovered in 2016, astronomers were almost sure they had detected a brown dwarf,
04:47which is an object too large to be a planet and too small to be a star.
04:54But later, scientists received proof that the space object wasn't big enough to be a brown dwarf.
05:00The planet sure is a mammoth among its peers.
05:03It's 1.2 times as wide as the largest planet of the solar system, Jupiter,
05:08and more than 12 times as heavy.
05:11Astronomers think the exceptional strong magnetic field helps the planet produce the auroras.
05:16But the most curious thing is that they're generated in a different way than auroras on Earth.
05:21It might be because the exoplanet's moon helps the planet create these light shows.
05:29If you travel 20,000 light-years away from Earth,
05:32you'd come close to a red dwarf in the Sagittarius constellation.
05:36Such stars are very cool and small.
05:39Quite far away from this cold star, there's a planet.
05:44The distance between this world and its host star is so great that the planet receives very little heat.
05:51It's one of the coldest planets ever detected.
05:54The average surface temperature on the planet is lower than negative 360 degrees Fahrenheit.
06:02That's why the entire planet is covered with a thick layer of ice.
06:06If you stepped onto its surface, you'd see nothing but glaciers, plains, and mountains of ice.
06:12And still, astronomers claim life might exist deep beneath the frozen surface.
06:18All because the core of the planet is likely to generate enough heat to melt some of its inner ice.
06:23In this case, there would be an enormous subsurface ocean,
06:27maybe even swarming with bizarre life forms on the planet.
06:32One of the oldest exoplanets we know about is PCR B162026b.
06:39It's about 12.7 billion years old.
06:42It's almost three times as old as Earth, which appeared 4.5 billion years ago.
06:48This also means that the Genesis planet formed only about 1 billion years after the Big Bang.
06:54The planet is so old that its two parent stars have had enough time to evolve into a white dwarf
07:01and a pulsar,
07:02making almost 100 revolutions per second.
07:06Sunrises on this planet must look awesome!
07:11I bet the next exoplanet isn't like any other you might have seen before.
07:16It's often called Super Saturn, or Saturn on steroids.
07:20That's because J1407b has a colossal system of rings.
07:26They're 640 times as large as those of Saturn.
07:30The bizarre world is 434 light-years away from Earth.
07:34It's the only planet we know about that has rings similar to Saturn's.
07:39If you moved J1407b to our solar system and replaced Saturn with it,
07:45its rings would look many times larger than a full moon.
07:51Astronomers have noticed a gap halfway through the planet's rings.
07:54The chances are high that an exomoon the size of Mars orbits the planet somewhere within this gap.
08:00If you lived on this moon, you'd have an awesome view every time you looked up into the sky.
08:07This exoplanet, called WASP-12b, munches on the light coming from its star.
08:12It's one of the darkest worlds people know about.
08:15All because its dayside consumes light rather than reflects it back into space.
08:21The planet is giant, twice the size of Jupiter,
08:24and it traps more than 94% of the light that reaches its atmosphere.
08:28This is likely to be the main reason for the insane temperatures on the surface of the planet.
08:33They can rise up to 4,600 degrees Fahrenheit.
08:37It's almost half as hot as the surface of the sun.
08:42WASP-12b travels so close to its host star that it needs just one day to complete one orbit.
08:49Its night side isn't as hot as the day side.
08:52A mere 2,200 degrees Fahrenheit.
08:55Because of this difference in temperature, water vapor and clouds gather above the surface of the planet.
09:01From time to time, swirls of material from the planet's superheated atmosphere spill onto its star.
09:08About 4,000 light-years away from Earth, there's an exoplanet that might be one enormous diamond.
09:15It's 5 times the size of our planet, but needs only 2 hours and 10 minutes to orbit its parent
09:21star.
09:22It's a pulsar rotating at a rate of 10,000 times a minute.
09:28The planet is denser than any other we've discovered so far.
09:32It consists mostly of carbon, which is so dense that astronomers think it might be crystalline.
09:37If it was true, it could mean that at least some part of the planet is diamond.
09:44On WASP-76b, it rains iron on the night side of the planet,
09:48and the temperature on the daytime side rises up to 4,300 degrees Fahrenheit.
09:54That's hot enough to vaporize most metals.
09:58This exoplanet is a bit smaller than Jupiter and located 640 light-years away from Earth.
10:04Such terrifying weather conditions in this world are caused by its unusual orbit.
10:09The distance between WASP-76b and its parent star is 10 times shorter than the distance between Mercury and the
10:17Sun.
10:17That's why the star and the huge planet are tidally locked.
10:21One side of WASP-76b always faces the star, and the other side is always pitch black.
10:30This bright blue exoplanet sits 62 years away from Earth.
10:34A bit larger than Jupiter, it looks calm and peaceful.
10:38Its blue color might remind you of our home planet.
10:41But this familiar appearance conceals the planet's horrifying nature.
10:46The beautiful hue comes from silicate atoms and particles that make up the atmosphere.
10:52But the wind speed on the planet can reach 5,400 miles per hour.
10:57That's seven times the speed of sound.
10:59The temperature there can rise up to 1,600 degrees Fahrenheit.
11:04But this isn't the worst.
11:06In this bizarre world, it rains glass, sideways.
11:10So it's probably not the place where you'd like to spend your vacation.
11:19What if the strangest planets in the universe aren't the ones from science fiction,
11:24but the ones astronomers have already found?
11:27One of the strangest planets ever discovered looks blue from space.
11:32At first glance, it almost resembles Earth.
11:35But temperatures there exceed 1,000 degrees Celsius.
11:39And scientists believe hurricane force winds blast molten glass through the atmosphere
11:45at over 8,000 kilometers per hour.
11:49And somehow, this isn't even the strangest exoplanet we've found.
11:54One of the most famous examples is HD 189733-b,
11:59located about 64 light-years from Earth.
12:03From a distance, the planet appears deep blue,
12:06almost resembling our own world.
12:09But its atmosphere is filled with silicate particles,
12:12essentially tiny fragments of glass.
12:15Combined with temperatures above 1,000 degrees Celsius
12:19and winds reaching more than 8,000 kilometers per hour,
12:23these particles are blasted sideways through the atmosphere.
12:28Scientists believe this creates one of the most violent weather systems
12:32ever observed on a planet.
12:35Another world that seems impossible is WASP-12b.
12:39This gas giant orbits so close to its star
12:42that a year there lasts only about 26 hours.
12:46The planet receives extreme amounts of radiation
12:49and has been stretched into an egg-like shape by gravity.
12:54Observations show that material from the planet
12:57is actively being pulled away by its parent star.
13:01Astronomers are literally watching a planet lose mass
13:04as it slowly gets consumed.
13:07Then there is Trias-2b,
13:09often called the darkest known planet.
13:12This world reflects less than 1% of the light that reaches it.
13:16Fresh asphalt on Earth reflects more light.
13:19Scientists believe unusual chemicals in its atmosphere
13:23absorb almost all incoming visible light,
13:26making the planet appear nearly black
13:29against the surrounding darkness of space.
13:31Despite temperatures exceeding 1,000 degrees Celsius,
13:35it remains one of the least reflective objects ever discovered.
13:40Perhaps the most famous exoplanet on the Internet
13:43is 55 Cancri e.
13:45This super-Earth is roughly twice the size of our planet
13:49and orbits so close to its star
13:51that surface temperatures exceed 2,000 degrees Celsius.
13:56Early studies suggested its interior might contain
13:59enormous amounts of carbon compressed under immense pressure,
14:03leading to headlines calling it the Diamond Planet.
14:07While newer research suggests the picture is more complicated,
14:11scientists still believe the planet's geology may be radically different
14:15from anything found in our solar system.
14:18Some discoveries are strange because scientists still don't understand
14:22how they exist at all.
14:25TOI 849b appears to be the exposed core of a giant planet.
14:30It has roughly 40 times Earth's mass,
14:33but somehow lost nearly all of the thick atmosphere expected around an object of that size.
14:40Researchers believe it may be the naked core of a former gas giant,
14:44exposing layers that are normally hidden deep inside planets like Jupiter.
14:49An even bigger mystery is WASP-193b,
14:54one of the least dense planets ever found.
14:57The planet is larger than Jupiter,
14:59yet its density is so low that astronomers struggle to explain how it remains stable.
15:04Current models suggest its atmosphere is inflated to extraordinary proportions,
15:10creating a world that resembles a giant ball of gas far larger than expected for its mass.
15:17The most extreme temperatures may belong to KELT-9b.
15:21This giant planet reaches more than 4,000 degrees Celsius on its daytime side,
15:27making it hotter than some stars.
15:29At these temperatures, molecules cannot remain stable for long.
15:34Metals such as iron and titanium are believed to exist as vapor in the atmosphere.
15:40Scientists classify KELT-9b as one of the most hostile environments ever observed anywhere in the galaxy.
15:48Not all bizarre planets orbit stars.
15:51Astronomers have also discovered rogue planets wandering through interstellar space
15:56after being ejected from their original systems.
15:59Some estimates suggest there could be billions of these lonely worlds drifting through the Milky Way.
16:06Because they emit almost no light, they are extremely difficult to detect,
16:11which means many more may still be hidden in the darkness between stars.
16:15The most surprising thing about these discoveries
16:18is that they completely changed our understanding of planetary systems.
16:23Before the 1990s, scientists assumed our solar system was probably typical.
16:29Today, the evidence suggests the opposite.
16:32The universe appears to be filled with worlds far stranger
16:35than anything early astronomers imagined.
16:38And considering that we have explored only a tiny fraction of our galaxy,
16:43the strangest planet ever discovered may still be waiting to be found.
16:50So, what is the habitable zone?
16:53Well, in my room, it's the small section which isn't buried in food wrappings and video games.
16:58But astronomically speaking, it's a region around a star where the temperature of H2O matters.
17:06So, just like Goldilocks, the habitable zone is just right to allow liquid water to exist.
17:15And water is essential for life as we know it.
17:18Just ask the three bears.
17:20The size of this zone depends on the temperature of the star.
17:23But the habitable zone isn't necessarily a guaranteed oasis of life.
17:28Other factors, such as a planet's atmosphere and magnetic field, also play a crucial role in this.
17:35Scientists have discovered more than 5,000 planets outside our solar system.
17:40And only 63 of them are potentially habitable for life forms, like on Earth.
17:45Kind of a cosmic lottery.
17:47The good news is, this rule also works for the moons.
17:52If moons of planets are within the habitable zone,
17:55they may also have conditions suitable for life.
17:58That would be a jackpot in our lottery.
18:01Two oases for the price of one.
18:03In our solar system, this zone is within a range of 80 to 111 million miles.
18:09Of all the planets, only we were lucky enough to have life.
18:13But what if we could make all the planets in our solar system habitable?
18:18Well, let's start with Mercury.
18:20First off, we'd need to give Mercury a bit of a makeover
18:23by thickening its atmosphere and providing it with a magnetic field.
18:27So, let's shower it with some asteroids that contain water.
18:31It's terraforming time, baby!
18:34Mercury is the closest planet to the Sun, which means it gets plenty of sunshine.
18:38So, not that it needs any help in that department.
18:42Actually, Mercury needs to chill out a bit.
18:44Right now, it's 800 degrees Fahrenheit.
18:47That's too hot, said Papa Bear.
18:49That's why we should move it to a more habitable orbit,
18:52about twice as far away from the Sun as it is now.
18:56Now, thanks to terraforming and pleasant temperatures,
18:59we'd finally get some water.
19:01And if we want to get really cozy,
19:04we could always build habitats underground, or on the surface.
19:08But then we'd have to shield them from the heat and radiation.
19:11Anyway, with a little creativity, we could make it work.
19:15I mean, people live in Arizona, right?
19:17Yeah, but then we'd need a lot of golf courses.
19:20Let's move on to Venus.
19:22Ah, the famous planet of love.
19:24Where the temperatures are hot enough to melt lead,
19:27and the atmospheric pressure can crush you in seconds.
19:30Isn't it romantic?
19:32Venus is referred to as Earth's sister planet.
19:35But as it often happens with siblings,
19:38we have almost nothing in common.
19:40Well, let's try to solve this problem.
19:42If we add some hydrogen on Venus,
19:45it could react with a carbon dioxide in the atmosphere
19:47to form water and graphite.
19:50Water would help us to create some oxygen.
19:52But for this plan to work,
19:54we'd need to get hydrogen from space,
19:56like it's a Black Friday sale.
19:58After that, we can build our new homes.
20:01We'll just have to make sure the buildings are strong enough
20:04to withstand the winds and acid rain.
20:06Piece of cake, right?
20:08Luckily, with the next planet, things are much easier.
20:11Mars is often considered the most promising candidate
20:14for extraterrestrial life in our solar system.
20:17It's a rocky planet with a thin atmosphere,
20:20but it has signs of water on its surface.
20:23And not only water, but even microbial life.
20:27So the Martians must think of us as extraterrestrials.
20:31Anyway, if we're going to terraform Mars,
20:34adding oceans is a must.
20:36They'd thicken the atmosphere and warm the surface.
20:39Time for another asteroid shower.
20:41Or we could create some giant mirrors
20:43to reflect the sunlight and melt the ice caps.
20:46Easy peasy.
20:47And as soon as oceans appear on Mars,
20:50it'll gradually turn into a lush green planet,
20:53very similar to our Earth.
20:55After that, we'll just need to build
20:57some artificial habitats
20:58and make sure they have all the comforts of home.
21:01Now, making rocky planets habitable isn't that difficult,
21:05compared to the gas giants.
21:07Jupiter has no solid surface at all,
21:10and it's basically impossible to colonize.
21:13So let's get creative.
21:15We could build floating habitats in the clouds of Jupiter,
21:18where temperatures and pressures are more Earth-like.
21:21We just need to protect them from little inconveniences,
21:24like wind speeds of more than 400 miles per hour
21:27and lightning every other minute.
21:29But if we managed to build homes in Jupiter's atmosphere,
21:33we could have some truly unique views.
21:35Just imagine waking up every day
21:38and seeing swirling clouds and colorful bands out your window.
21:42Or taking a stroll through the gas giant's thick atmosphere.
21:45Scary and awesome.
21:47Just watch your step on that balcony.
21:50We could also use some high technologies
21:52to make Jupiter's atmosphere breathable.
21:55Something that would consume its gases and release oxygen.
21:58Now, this is pure sci-fi, but wouldn't that be cool?
22:02Let's move on to Saturn.
22:04It's also a gas giant,
22:05which has no solid surface for life to exist.
22:08But don't lose hope.
22:10Just like with Jupiter,
22:11we could create some floating habitats
22:13in the upper atmosphere of Saturn.
22:15Try living on a luxurious cloud,
22:18although the rent would be sky-high.
22:20We could also cover the planet with a giant shield,
22:24like a cosmic umbrella.
22:25In space, it's raining cosmic rays instead of water.
22:29But this barrier could protect us
22:31from harmful radiation and solar winds.
22:34Thanks to this,
22:35the weather on Saturn would become a bit calmer.
22:38Also, remember how we were talking about moons?
22:41One of Saturn's moons, Titan,
22:43has a dense atmosphere,
22:44and maybe even a subsurface ocean of water.
22:48Enceladus also hides an ocean beneath its crust.
22:51Both of them might be perfect places
22:54for actual colonization.
22:55That would be much easier than colonizing Saturn.
22:58Uranus is another ice giant
23:01made up of dense, fluid, icy materials.
23:04Methane, ammonia, and water.
23:06Considering the surface temperature of
23:08minus 353 degrees Fahrenheit,
23:11you could say it's pretty chilly out there.
23:14So how do we make this work?
23:16Well, we could try to create a greenhouse effect.
23:19It's a natural process that helps keep
23:22the Earth's temperature stable and pleasant,
23:24unless we mess around with it.
23:26When sunlight enters the Earth's atmosphere,
23:29some of it gets trapped by gases called greenhouse gases.
23:33They act like a blanket around the Earth,
23:35keeping the planet warm,
23:37unless we mess around with it.
23:38So, if we want to make this ice giant warmer,
23:42we can try to recreate this effect,
23:44only better.
23:45For example,
23:46we could introduce some of these gases
23:48into Uranus's atmosphere,
23:50or build a network of mirrors
23:52to trap the heat from the Sun.
23:54Although it would require tons of giant mirrors,
23:57and just imagine trying to position them all correctly.
24:01So, instead of all this headache,
24:03we could always set our sights on Uranus's moons.
24:06They're believed to have rocky surfaces,
24:08and maybe even oceans that could support life.
24:12Plus, the views are out of this world.
24:15Moving on to the final planet, Neptune.
24:18The cool, distant cousin of the Solar System.
24:21It's also a nice giant.
24:23Its year lasts 165 Earth years.
24:26Now first, let's create an atmosphere.
24:28Neptune's atmosphere is mostly made up
24:31of hydrogen, helium, and methane.
24:33Pew.
24:34We'd need to transport some plants there,
24:36or simply lots of oxygen,
24:38to make this place a bit more breathable.
24:41And how do we add water to a gas giant?
24:44Maybe by melting ice from the moons,
24:46or by transporting large amounts of water from Earth.
24:50Just imagine a squadron of spaceships
24:52dragging giant containers to Neptune.
24:55And then, once the planet has a breathable atmosphere
24:58and liquid water,
25:00we'd need to build habitats.
25:02Probably another sky city,
25:04because you can never have enough of those.
25:06So, let's say we somehow magically
25:09made all the planets habitable.
25:11Now what?
25:12Well, there would be a boost
25:14in human exploration and colonization.
25:16People would build new homes on different planets.
25:20Imagine immigrating from Mercury to Neptune
25:22because you prefer chilly temperatures more.
25:25With more habitable planets to study and explore,
25:29scientists would learn more about our world.
25:31We'd have so many breakthroughs.
25:33Also, it's time for some interplanetary trade.
25:36We could mine tons of resources
25:38from planets, asteroids, and moons.
25:41A dream come true for Elon Musk.
25:43But of course, it's not all fun and games.
25:47All of this would most likely lead to conflicts
25:49over resources and territory.
25:51Imagine trying to keep peace
25:53between Jupiterians and Martians.
25:56Well, all jokes aside,
25:58the possibility of all planets being habitable
26:01is mind-boggling.
26:02But in reality,
26:04terraforming planets like this is impossible,
26:07at least for now.
26:08But who knows?
26:09Many things were considered impossible before.
26:12But this didn't stop us.
26:14So, let's keep dreaming.
26:16Meanwhile, we can clean up the planet
26:18we're already on.
26:20Spotted, it seems like two giant stars
26:23were caught in the middle of a romantic kiss.
26:25This sounds a little bit like paparazzi fodder at first.
26:29But we're actually talking about a cosmic twist
26:32an international team of astronomers has discovered.
26:37So, the life cycle of a solo star is relatively simple.
26:41They're born in vast, gassy areas of space,
26:44burn through their fuel,
26:45and at some moment, they explode as supernovae.
26:49But when stars are born relatively close to each other,
26:52their gravitational pull can cause them some troubles
26:55and captivate them into what seems like an eternal dance.
27:00In some moments,
27:01they come so close to each other
27:03that they're practically touching.
27:05These stars may spend billions of years
27:08circling each other,
27:09but their kiss lasts for a few million years only,
27:12which is just a blink of an eye in cosmic terms.
27:17The lead author of this study
27:19was on a mission to find these binary stars
27:22caught in such a cosmic kiss.
27:24He focused his search on the Tarantula Nebula,
27:28a beautiful star-forming region
27:30located in the Large Magellanic Cloud,
27:33which is 160,000 light-years away
27:36from our home planet.
27:37And there it was,
27:39the shiny double star system
27:41that stood out from the rest.
27:43The two stars found there were pretty big
27:46and nearly the same size.
27:48Together, they make a mass
27:49of about 57 times larger than that of our Sun.
27:53Before this,
27:55we discovered only three other binary systems
27:57with a large mass.
27:59And since these two stars
28:00were so close to each other,
28:02they created an intense gravitational pull.
28:05This made them orbit each other
28:07at a staggering rate of once a day
28:09with their centers a mere 7.4 miles apart.
28:14With the stars being so close,
28:17they formed a bridge
28:18where their fuel could mingle,
28:20allowing for around 30% of their total volume
28:23to be shared between the two.
28:25Temperatures of this system were crazy too.
28:29At first,
28:30it seems the internal mixing of their energy
28:33might make these stars live longer,
28:35as it allows for more fuel to be burned
28:37and for longer periods of time.
28:39But this is just a temporary benefit.
28:42There are two most likely scenarios
28:44for the star's ultimate fate.
28:46They could merge to form one giant star,
28:50which would eventually explode
28:51into a supernova.
28:53Or,
28:53they could each explode separately
28:55and live out their remaining years
28:57as black holes orbiting each other.
29:01If they merge,
29:02this process would probably take
29:04around 600,000 years,
29:06while if they become binary black holes,
29:09they could continue burning
29:10for another 3 million years.
29:13But both scenarios
29:14would ultimately lead
29:15to their destruction.
29:17Unless the stars could end up
29:19as two separate black holes
29:21drifting away from each other
29:22through the vastness of space,
29:24there's a possibility
29:25for that to happen too.
29:27There's something spectacular
29:29stargazers across the globe
29:31could see recently.
29:33Jupiter and Venus,
29:34the two brightest planets in the sky,
29:37ended up so close
29:38it appeared like
29:39they were about to collide.
29:40Or as if they were kissing too.
29:43At least that's what it looked like
29:45from here on Earth.
29:46In real terms,
29:47they're still 400 million miles
29:49away from each other.
29:51Here's another interesting thing
29:52astronomers like to talk about.
29:54G-objects.
29:55Those are celestial objects
29:57that look like clouds of dust and gas,
30:00but behave like stars.
30:03At the center of our galaxy,
30:05there's a supermassive black hole.
30:08It's 4 million times
30:09the mass of our sun.
30:11And recently,
30:12scientists found out
30:13there are two mysterious G-objects
30:16that hang out pretty close
30:17to that black hole,
30:19so-called G1 and G2.
30:22And the most probable theory
30:24is that G2 are two stars
30:26that were orbiting the black hole
30:28in tandem
30:29and merged into an extremely large star
30:32cloaked in unusually thick gas and dust.
30:36During G2's closest approach
30:38to the black hole,
30:39it showed a strange signature.
30:41It was elongated
30:43and much of its gas
30:44was torn apart.
30:45As it got closer to the black hole,
30:48it lost its outer shell
30:49and now it's getting more compact again.
30:53The thing that has everyone excited
30:56about the G-objects
30:57is the material that gets pulled off of them
30:59by tidal forces
31:00as they sweep by the central black hole.
31:04This material must inevitably fall
31:06into the black hole
31:07and the result
31:08is an impressive fireworks show.
31:11This happens because
31:12the material eaten by the black hole
31:14will heat up
31:15and emit radiation
31:16before it disappears
31:18across the event horizon.
31:20An event horizon
31:21is that scary boundary
31:22around a black hole
31:24from which nothing can escape.
31:27Now, it seems scientists
31:29have discovered
31:29four more G-objects
31:31and they're all located
31:33within 0.13 light-years
31:35of this black hole.
31:36And it could be
31:38that all of the six objects
31:40used to be binary stars
31:41that got together
31:43and merged
31:43because of the powerful gravity
31:45of this giant black hole.
31:48Usually,
31:49it takes over a million years
31:51to finish the merging process
31:52between two stars.
31:54We definitely want
31:55more G-objects
31:57because it's one of the rare opportunities
31:59for us to study
32:00how things behave
32:01near a supermassive black hole
32:03without being swallowed
32:05yet.
32:07Have you heard
32:09of variable stars?
32:10Look up at the sky.
32:12We often think of the stars
32:13as unchanging,
32:14eternal lights.
32:16Yes,
32:17some stars might appear constant,
32:19but others change
32:20in brightness over time,
32:21which is why we call them
32:23variable stars.
32:24Some of them dim
32:26and brighten again
32:27over days,
32:28months,
32:28or even years.
32:29We can't see it
32:31with the naked eye.
32:32We're talking about changes
32:33astronomers can only notice
32:35using equipment
32:36and over longer periods.
32:39And how about vampire stars?
32:42Imagine two stars,
32:44a red giant
32:45and a white dwarf
32:46in a binary system,
32:48swirling around each other
32:49like cosmic ballet dancers.
32:51The red giant,
32:53which used to be a vibrant
32:54and fiery star,
32:56now has aged
32:57and grown tired.
32:58Its outer layers of hydrogen,
33:00which were once held tightly
33:02by its gravity,
33:03have now weakened,
33:04making it vulnerable
33:05to the smaller,
33:06denser white dwarf.
33:07The white dwarf,
33:09known as the vampire star,
33:11thirsts for the hydrogen fuel
33:13that its larger sibling holds,
33:15and it sees a great chance there.
33:18As they spin together,
33:20the vampire star
33:21uses its powerful
33:22gravitational force
33:24to steal the hydrogen
33:25from the red giant's
33:26outer layers.
33:27The vampire star
33:28glows with a blue hue,
33:30looking full of energy
33:32and more youthful
33:33and vibrant
33:34than its aged dancing partner.
33:36Not only vampire stars,
33:39the horror continues
33:40with zombie stars too.
33:42Sometimes,
33:43when the red giant explodes,
33:45it doesn't completely
33:46break up
33:46into smaller pieces.
33:48Instead,
33:49a white dwarf remnant
33:50is left behind.
33:52It's basically
33:53a zombie star
33:54that was gone
33:54at the moment,
33:55but has risen
33:56back to life.
33:58But this isn't
33:59your average zombie,
34:01hungry for brains.
34:02No,
34:02this star hungers
34:04for the very substance
34:05that its vampire sibling
34:06had been taking
34:07from it all along.
34:08Hydrogen.
34:09And if the zombie star
34:11is close enough
34:12to its victim,
34:12it will start
34:13sucking material back in
34:15to start its core again.
34:17It will become
34:18a hydrogen explosive,
34:20ready to go boom
34:21in a spectacular show
34:22of cosmic revenge.
34:24It's a fascinating phenomenon.
34:26We usually won't even
34:28manage to detect it,
34:29because these explosions
34:31are much fainter
34:32than the usual supernovas.
34:33But when it does happen,
34:35the resulting blast
34:36is truly epic.
34:38And it destroys
34:40both the vampire star
34:41and its zombie sibling.
34:43It seems vampires
34:44and zombies
34:45may not be
34:46a work of fiction
34:47after all.
34:49Not only are we
34:50made of stardust,
34:51but we're also
34:52more similar to stars
34:53than we thought too.
34:55For example,
34:56stars also like
34:57to hang out
34:58with their close
34:58group of friends.
34:59Most stars prefer
35:01to travel through
35:01the universe
35:02in clusters.
35:03It's a group of stars
35:04that end up bound together
35:06by gravitational force.
35:08The stars in the cluster
35:09are mostly made
35:10of the same age
35:11and type,
35:12hobbies,
35:13and interests.
35:14I guess even they
35:16have better social lives
35:17than I do.
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