00:00NASA 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 some sort of gigantic solar panel.
01:09Advanced civilizations could use it to power their planet and even interstellar travel.
01:14Right now, something like this would be impossible for us to build.
01:18But maybe someone else in the universe has managed to pull that off.
01:21Scientists 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 techno-signatures.
01:46These are weird things that might indicate the presence of something technological and can't be explained by known natural sources, like galaxies or nebula.
01:57For example, a structure like a Dyson Sphere could give off unusual infrared radiation.
02:02This is because, while absorbing a star's energy, this structure would give off crazy amounts of heat.
02:11Out of millions, they identified 368 potential candidates.
02:16Further filtering left them with only 7 objects that could be Dyson spheres.
02:20Now, 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.
02:39The 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 dwarf.
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.
03:03There was another study that found 53 star candidates with similar excess infrared radiation.
03:11But 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 of these candidates.
03:21One famous candidate is Tabby's star.
03:25Scientists 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 flashlight.
03:48At first, you might think this is just because some big planet is passing in front of it, or a comet.
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.
04:09Someone also suggested that the dips might be caused by fragments from a broken exomoon orbiting the star.
04:16There 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.
04:30There are many variations of what a Dyson sphere could look like.
04:34Rings.
04:35Bubbles.
04:35A swarm of satellites.
04:38A giant shell.
04:39And so on.
04:41A 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 around the sun.
05:06A Dyson swarm is the simplest option.
05:09A bunch of solar-collecting satellites and habitats orbiting the star.
05:14It 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, and terraform planets within the star system.
05:46But 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.
06:06They also look at the planets.
06:07Now, planets must have certain characteristics to be potential homes.
06:13There should be liquid water and an energy source, something 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.
06:31Unfortunately, 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 K-218b, which is pretty close, about 120 light-years from Earth.
06:55This planet is nine times the size of Earth.
06:57It 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!
07:31Models 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 funny, wiggly ways.
07:51These horseshoe systems can hold up to 24 planets.
07:54This 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, it might indicate that some advanced civilization decided to lend a hand.
08:14The search for extraterrestrial intelligence began in the 1960s, when astronomer Frank Drake started listening for radio signals from space.
08:28Today, 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 radiation.
08:57But YZ-SETI-B is probably too close to its star to be habitable.
09:01But 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, making 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?
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