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Astronomers have uncovered compelling evidence of advanced civilizations in distant star systems, and NASA has found a "super-Earth" planet close to us—raising new questions about extraterrestrial life.
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00:01NASA is on the hunt for Dyson Spheres.
00:04Turns out there are 60 stars that give off weird light patterns.
00:08This means there might be some extraterrestrial technology nearby.
00:15A team of scientists has developed a new way to search for advanced civilizations by looking for Dyson Spheres.
00:21All forms of life, from microbes to us, need energy in order to survive.
00:26As living creatures keep evolving, their energy needs grow.
00:31We started with small fires, then moved on to coal, oil, and eventually solar panels.
00:38Now imagine a super advanced civilization that has used up all the energy sources on its planet.
00:44What's next?
00:46Their host star, an almost limitless power source.
00:50This is where the idea of Dyson Spheres comes in.
00:53It was made up by the physicist Freeman Dyson in the 1960s.
00:58This idea says that, hypothetically, we could build an incredibly big structure around a star to capture its energy, like
01:06some sort of gigantic solar panel.
01:08Advanced civilizations could use it to power their planet and even interstellar travel.
01:13Right now, something like this would be impossible for us to build.
01:17But maybe someone else in the universe has managed to pull that off.
01:23Scientists gathered lots of data from surveys of stars.
01:27They analyzed over 5 million objects and found some candidates.
01:32Of course, extraterrestrial civilizations might have completely different technology.
01:37So, astronomers aren't looking for actual giant shells around stars.
01:42Instead, they're looking for technosignatures.
01:46These are weird things that might indicate the presence of something technological and can't be explained by known natural sources
01:53like galaxies or nebulae.
01:57For example, a structure like a Dyson Sphere could give off unusual infrared radiation.
02:03This is because, while absorbing a star's energy, this structure would give off crazy amounts of heat.
02:10Out of millions, they identified 368 potential candidates.
02:16Further filtering left them with only 7 objects that could be Dyson spheres.
02:23Now, usually, weird infrared flickering happens from giant crashes in space, like planetary collisions.
02:31Warmed-up dust and rocks get scattered around and give off strange lighting patterns.
02:37These are called extreme debris disks.
02:40The researchers think these 7 objects could be M-type stars, also called red dwarfs.
02:46These are stars that are very small on the space scale and a bit fainter than our sun, a yellow
02:52dwarf.
02:54Stars like that don't usually have warm dust and rocks around them.
02:57But scientists need to do more tests, like looking at the light in detail, to be sure about their discovery.
03:04There was another study that found 53 star candidates with similar excess infrared radiation.
03:10But these also need to be checked.
03:13Scientists plan to use advanced tools, like the James Webb Space Telescope, to take a closer look at all these
03:19candidates.
03:21One famous candidate is Tabby's star.
03:24Scientists even made a joking name for it, because the paper about this star had the subtitle,
03:29where's the flux?
03:31Think of an acronym yourself.
03:33Now, it's a bit hotter and more massive than our sun.
03:36It's caught NASA's attention because of its unusual, irregular light dimming.
03:41For some reason, it doesn't glow like a normal star, but blinks, as if someone turns on and off a
03:47flashlight.
03:48At first, you might think this is just because some big planet is passing in front of it, or a
03:54comet.
03:54But we're talking up to a 22% drop in light.
03:58No planet could manage to eclipse a quarter of a star.
04:01And that's where the name comes in.
04:04So, another explanation is a Dyson sphere or some similar megastructure.
04:08Someone also suggested that the dips might be caused by fragments from a broken exomoon orbiting the star.
04:17There are other stars that show similar traits, but there's no solid evidence to support this.
04:22So, for now, scientists just don't know.
04:26So, astronomers are on the hunt for any giant structures.
04:29There are many variations of what a Dyson sphere could look like.
04:33Rings, bubbles, a swarm of satellites, a giant shell, and so on.
04:40A Dyson shell would be a solid, rigid shell, completely enclosing the star.
04:46This is the most extreme option, the hardest one to build.
04:50Also, if other civilizations built that thing, it would fully cover the star's light, and we simply wouldn't see it.
04:57The inner surface of this shell could be lined with habitats, and we could simulate gravity by rotating the structure
05:04around the Sun.
05:06A Dyson swarm is the simplest option.
05:09A bunch of solar-collecting satellites and habitats orbiting the star.
05:13It would be a lovely place, with people living in many space stations or many space houses within the swarm.
05:20Each little habitat would have its own air, life support systems, and artificial gravity.
05:25We could also grow our little farms there.
05:28And imagine the view.
05:30We would see a constant bright sky with other habitats visible across the expanse.
05:36A near unlimited energy of a star would mean we could advance our technology very fast, manufacture tons of materials,
05:44and terraform planets within the star system.
05:47But building and maintaining a Dyson sphere would require advanced robotics, AI, and tons of money.
05:55It would take us centuries or millennia to get there.
05:59Giant megastructures aren't the only things that scientists are looking for in order to find extraterrestrial life.
06:05They also look at the planets.
06:08Now, planets must have certain characteristics to be potential homes.
06:13There should be liquid water and an energy source.
06:16Something to drive these reactions, creating the building blocks of life.
06:22Turns out, such conditions aren't rare at all.
06:25Our search showed that there might be more than 60 billion potential habitable planets in the Milky Way alone.
06:32Unfortunately, we can't look at them directly or land there.
06:37So, we have to use tricks, like detecting water and good gases in their atmosphere.
06:43Recently, the James Webb Space Telescope found possible signs of life on a planet called K218b, which is pretty close,
06:52about 120 light-years from Earth.
06:54This planet is nine times the size of Earth.
06:58It has clouds of liquid water but a different atmosphere, full of gases like methane, carbon dioxide, and dimethyl sulfide.
07:07Regular oxygen-breathing life wouldn't do well at all there.
07:10But on Earth, dimethyl sulfide is produced by life forms like photoclankton.
07:17They also discovered that weird, wiggly planets could be signs of advanced extraterrestrial civilizations.
07:23In our solar system, each planet has its own orbit.
07:27But the universe likes to surprise us.
07:30Surprise!
07:30Models show that there might be planets that share the same orbit.
07:34For example, it's possible if the planets are evenly spaced around the star, minimizing their gravitational impact on each other.
07:42Or the so-called horseshoe configuration, when planets speed up and slow down in relation to each other, moving in
07:49funny, wiggly ways.
07:50These horseshoe systems can hold up to 24 planets.
07:55This is one of those things that are possible, but very unlikely, without some help.
08:00Normally, gravity would immediately destabilize such systems.
08:05This means that if we ever find a star system with 24 planets sharing orbits,
08:10it might indicate that some advanced civilization decided to lend a hand.
08:16They also might contact us themselves.
08:19The search for extraterrestrial intelligence began in the 1960s, when astronomer Frank Drake started listening for radio signals from space.
08:29Today, they persist.
08:31Astronomers listen for leakage radiation from other civilizations, which are radio waves unintentionally sent into space from everyday activities.
08:40Recently, they detected radio waves from YZ-SETI-B, a planet super close to us, just 12 light-years away.
08:49This means it might have a magnetic field, invisible shields that are very important for protecting life from the solar
08:56radiation.
08:57But YZ-SETI-B is probably too close to its star to be habitable.
09:02But there are a lot of places for such a signal to come from.
09:06It turns out, there are a thousand star systems in our galaxy where they can see us in the sky.
09:12All these stars have a perfect view of Earth passing in front of the Sun,
09:16making it easy for potential extraterrestrial astronomers to spot us.
09:21So, there are over a thousand star systems that could be watching us right now.
09:25And if we study them, we might one day find evidence of intelligent life looking back at us.
09:32Hello!
09:34A new super-Earth has been spotted by astronomers, and it's quite intriguing.
09:40This planet, called TOI-715 b, is about one and a half the size of Earth, which is why it's
09:47called the super-Earth.
09:48It's also relatively close to us in space terms, only 137 light-years away.
09:54For comparison, most exoplanets are hundreds of light-years away.
09:58And all the interesting stuff, like black holes and nebulas, are usually more than thousands of light-years away from
10:05us.
10:05So, could it be habitable?
10:09The habitable zone is an estimate of where a planet might have the right conditions for liquid water.
10:15This is what we call some distance from the star, where the temperatures on the planet should be okay-ish,
10:21and water should stay liquid on its surface.
10:24It's not super precise, because it depends on a bunch of factors, like the type of star, how reflective the
10:31planet is, its size, and so on.
10:33Also, just being in this zone isn't enough for water to actually be there.
10:38The planet also needs the right kind of atmosphere and a few other things.
10:43So, we invented a stricter definition in 2014, the conservative habitable zone.
10:49It's a more precise term defining the best candidates that have liquid water.
10:53Otherwise, we get too many potentially habitable planets that are not actually habitable at all.
10:59The CHZ is based on how much energy a planet gets from its star compared to Earth.
11:05If a rocky planet gets between 40 to 85%, it's considered to be in the CHZ, no matter how far
11:14away it is from its star.
11:15These planets have a higher chance of being habitable.
11:19And yes, TOI 715 b is located there.
11:26This super-Earth orbits the M-type star, also called red dwarf.
11:31It's a star that's much smaller and cooler than our sun, about a quarter of the sun's size and mass.
11:37But if the planet is located in the habitable zone, it's actually a better option for life.
11:42Red dwarfs live much longer than our sun, a yellow dwarf.
11:46This also means that they have more time to form little creatures on their planets.
11:50And this red dwarf really is older than our star.
11:54Our sun is 4.6 billion years old.
11:57And this star is 6.6 billion years old.
12:00Give or take a few hundred million.
12:02It doesn't have much magnetic activity, so it's not dangerous.
12:07It doesn't flare up like younger red dwarfs.
12:09These flares can be super strong and might even hurt planets by taking away their atmospheres.
12:14Although some planets around it do have thinner atmospheres, it seems like this red dwarf has already gone all out.
12:23These red dwarfs are where we're looking for planets that could support life right now.
12:28Our super-Earth is really close to its star, zooming around it in just 19 days.
12:33Since the star is small and the planet is so close, the planet passing in front of its star happens
12:40a lot and looks really clear.
12:41This makes it easy for telescopes like the James Webb to study its atmosphere without needing too much time.
12:49Now, speaking of the James Webb Space Telescope, it's bringing us into a new era of understanding distant planets beyond
12:56our solar system.
12:58Imagine being able to see what gases make up the air on a planet millions of light-years away.
13:04James Webb will help us to find worlds that could support life.
13:08Right now, it's trying to figure out whether TOI 715b has an atmosphere.
13:14If it does, its atmosphere might be easier to spot compared to a planet that's drier and denser.
13:20And then, we might get even more height because it would look like a good place for life.
13:25On top of all that, there might be another planet in this system, also in the habitable zone.
13:31We're not sure whether it's really there, it's just a candidate with a crazy name.
13:36But if it turns out to be real, it would be about the size of Earth.
13:41Also, it would be the smallest planet in the habitable zone ever spotted by the TESS telescope.
13:48Another cool thing about TOI 715b is that it cannot just have water on it, but be an entire water
13:57world.
13:57An ocean planet is a type of planet that has an ocean covering its surface or has subsurface oceans.
14:03They might not have much dry land because the water can cover everything.
14:08Sometimes, the entire planet can be covered in other liquids, like lava or ammonia.
14:13When it comes to planets outside our solar system, we can't see surface water directly with our current technology.
14:20Instead, scientists look for water vapor in the atmosphere as a hint there might be liquid water below.
14:26And, of course, we wonder if these planets can have life, hopefully not in the form of Leviathan-like monsters.
14:34Our models show that planets with oceans might be pretty common in our galaxy.
14:39This means there could be lots of ocean worlds out there waiting to be discovered.
14:46But the most important part about TOI 715b is that it's in the so-called small planet radius gap.
14:54If we give the planets a lineup, there will be those that are bigger and smaller than Earth.
15:00But there's a sudden gap in planets that are about from one and a half to two times bigger than
15:05ours.
15:06Where are they?
15:07This gap is interesting to scientists because it tells us something about how planets form and change over time.
15:14It's not that planets don't form in this size range.
15:17They actually start off larger and then lose some of their mass, like a balloon gradually deflating.
15:23Perhaps it happens because of how they orbit their stars, with stars blowing away some of their mass as they
15:30dance around it, as our Sun does with gas from comet tails.
15:33This gap holds a lot of mystery.
15:36And planets, like our new super-Earth, are clues that could help us unravel it.
15:41We aren't sure whether it exists around red dwarfs.
15:44Maybe it's a gap in how dense these planets are, rather than in their actual size.
15:49So studying our discovered planet is even more interesting.
15:53It'll help us learn more about distant stars and their planets.
15:57Now, I mentioned TESS a while back.
16:00NASA's TESS, Transiting Exoplanet Survey Satellite, has been in space for six years now and has been incredibly successful.
16:09NASA launched TESS because we already found over 5,000 planets orbiting other stars, mainly thanks to the Kepler telescope.
16:18But Kepler mostly found large planets, not necessarily like Earth.
16:22We decided to focus TESS on finding smaller Earth-like planets around nearby bright stars, making them easier to study
16:30with future telescopes.
16:33Here's how it works.
16:35The camera observes stars and looks for changes in their brightness.
16:38If the brightness suddenly drops for a while and then gets back, it could mean there is a planet passing
16:45in front of it.
16:45But stars can dim for other reasons, too.
16:48For example, flaring up or having dark spots on their surface, which is why we need to be careful with
16:55this data.
16:56TESS shows us the size and orbit of these planets.
16:59Then, ground telescopes help determine their mass.
17:02With these three parameters, we can figure out what the planets are made of and if they're rocky like Earth
17:08or gassy like Jupiter.
17:10Yeah, you want to avoid Jupiter after taco night.
17:16One example of TESS's discoveries was the TOI-700 system.
17:21There, it discovered its first-ever Earth-like planet, TOI-700d.
17:26This exoplanet also orbited a red dwarf, and it's even closer to us, about 100 light-years away.
17:33Unfortunately, it's unlikely to be habitable because the temperatures there are crazy.
17:38Another big discovery was made in the AU microscopy system.
17:43TESS discovered a planet about four times the size of Earth and another nearly three times Earth's size.
17:49This system has become a key area for studying how stars and planets form and change over time.
17:55TESS has also spotted a variety of other exciting finds, including supernovae, hot worlds, and so on.
18:03And as it enters its sixth year, we can only expect more exciting findings to come.
18:08It's an intriguing point.
18:09Yet it's a difficult point.
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