Do Aliens Exist? If they do, would we know? - sciencenerds

One of the most important questions is, could there be another life besides us in the universe? And I think that almost all the scientists I know feel that there should be. I mean, simply the numbers: in our galaxy alone, there are half a billion stars. And now we are beginning to realize that almost all stars have their own solar system. At least, our unique galaxy has hundreds of billions of planets. And some of the stars are even older than our sun. There may be an opportunity for a civilization to begin billions of years before life began on earth.

And if that is true, could there be extraterrestrial civilizations that are much more technologically advanced than us? The unfortunate thing, of course, is that we have no evidence of this. They are not making it very obvious. So, is there any way we can see some of at least the artefacts of one of these super civilizations around a distant star? And one of the people who thought about this in a really wonderful way was a man named Freeman Dyson. And his name lent itself to something called the Dyson sphere. And what is a Dyson sphere: the idea is that a very advanced civilization would probably need a lot of energy. And one of the best sources of energy is solar energy, the energy of its star that orbits around. But instead of waiting for the starlight to reach a planet and be placed in small detectors and solar cells, what would happen if civilization were a bit more assertive about it, and actually went to the star and built collectors giants around? that star? The idea of ​​a Dyson sphere is probably a bit extreme because some people wondered if a civilization could build a full shell around a star. And that shell would collect all available radiation from that star that they could use for any alien purpose in their super-advanced civilization.

Many people have suggested that perhaps Shell would not be stable. It would be very difficult to keep that really working and orbiting around a star. Then, maybe I could make a giant grid of huge collectors that would orbit the star and capture as much radiation as possible. So, a Dyson sphere, or a kind of the equivalent of that, having many, many detectors in orbit around a star, is a wonderful idea in science fiction. The question is, is there any way to detect one of these? And for some time, in reality, people have wondered, what would happen if you saw a lot of infrared radiation, heat radiation, coming from an object similar to a star, but you didn't see any visible light? Is it possible that there was a layer of material around that star used to collect all its energy, and that layer was heating up because it is around the star, but it did not let the light pass? There are very serious scientists who proposed to look for objects similar to stars that only have heat, but that does not have associated light. Unfortunately, we never found any of those either. A couple of years ago, however, something very dramatic happened. which happened during the Kepler mission. This was a mission that looked for planets around other stars. And the way Kepler looked for planets is basically looking at a part of the sky where you could see a couple of hundreds of thousands of stars at a time, and only looked at it for years. The telescope never moved. I looked at the same part of the sky for a long, long time. And then, over time, scientists watched if the starlight varied. In general of these stars, could each star vary as a planet rotates and makes a small eclipse so that the planet has to be perfectly aligned along our line of sight, but that can happen, there are many planets in many Different orientations around the stars in the sky?

So, if what is perfectly aligned, you would see a small eclipse. The planet would pass in front of a star. You would not see the planet itself, but you would notice the fall of the starlight. The star would dim slightly. So what happens if you notice that a single star in that field darkens every three days? Every three days, there is the same small attenuation that returns again and again. You realize that you have a planet there, a planet, in this case, that orbits every three days and blocks the light. We have even found planets in Earth-like orbits that revolve around once a year. 

Then Kepler found thousands of planets just by looking at this part of the sky. Now, normally, when a planet is placed in front of a star, the brightness decrease is very small, less than 1%. If you have a large planet, a planet the size of Jupiter, and maybe that planet is even very close to the star, a couple per cent may fall. The real effect is relatively small. The stars are much larger and brighter than any planet around them. So, the dive is just a small dive. And so, imagine the surprise of people a couple of years ago when one of the stars seemed to be experiencing very dramatic brightness drops, up to 25%. Now, the only thing that could block 25% of a star's light is something as big as another star, and then we would see another star spinning, and that wasn't there. We had never seen anything like this before.

And interestingly, this was done by what we call a citizen scientist. There are people in the public who are not trained scientists who really help NASA. They review our data. And they have no training. It is almost like a video game format. In fact, they help us review the data, and then point out things that are interesting. Obviously, we have computer programs that look for these variations in the starlight. And computer programs find 99% of everything we are looking for. But sometimes there is a strange result, something that does not match the computer algorithm, and the computer discards it. And that is what happened with this star. It was such a dramatic fall that it could not have been real. And not only that, the fall was not symmetrical. When you have a small ball, a small planet goes in front of a star, the fall is nice and symmetrical. It is a beautiful, even, circular shape that goes in front of the star. It had a very strange shape, almost as if giant triangles moved across the surface of the star.

So, scientists did not immediately conclude that, hey, maybe these are giant extraterrestrial solar collectors. But in the article that was published, the first author was Tabetha Boyajian, they noticed that if there was something like Dyson's sphere, it could look like this. And, of course, the press grabbed it and people wondered that if we could really have found evidence for the existence of a super civilization around the star. And actually, even myself, this star is about 60 light-years away and is visible through a small telescope. It is not a particularly bright star, but you can see it through a small telescope. And I was wondering if we could prove that this was artificial. You could go out to your backyard at night, put a telescope in the sky and see this little point of light, and know that there was something wonderful, amazing, a super civilization around that star. It gave me the chills. Of course, we wanted to follow up and find out what it really was. Could they really be giant solar collectors orbiting a star? Well, the unfortunate thing is that, after many follow-ups and looking at it in different wavelengths of light, there was a relatively simple discovery that everything is made of dust. In reality, it duplicates different wavelengths of light, different colours, differently, in the same way, that sunlight blushes in a water droplet.

As it descends through the air, the blue light disperses, the red light is left and you have a beautiful orange or red sunset. And whatever is made of dust. Unless aliens are particularly good at making giant solar particle collectors that are less than a millionth of a meter wide, it is not an alien civilization. Instead, we have a new mystery: what is this? There is a giant cloud of dust, opaque and thick around this star, and it is very uneven. And people wonder if maybe two planets have collided recently. Maybe two planets collided and threw this giant cloud of dust that is still settling. Maybe that is what we are seeing. We are not really sure. But One of the things I think he really says about this is that they often ask me, would you hide evidence of a civilization? Let's say we had extraterrestrial bodies or a UFO, or that we had found signs of space, would scientists hide that? from the public? And instead, I think what you saw were scientists jumping up and down, saying, oh my God, what if this is really something very interesting? We even called our SETI colleagues, the search for Extraterrestrial Intelligence, which is an organization that really looks for radio signals around the sky that could be produced artificially, we asked them to take a look at the star, where they didn't see anything, so although this didn't turn out to be an alien civilization, and in fact, we still don't have evidence of aliens, we love the idea that there could be life out there. 

As scientists, this excites us. It inspires us. And immediately, even before knowing if it was true or not, we wondered if it could be a possibility. There is no way we can do it. Never hide it And not only that, but the sky is open to all. There isn't a single country that can really-- you're the only people who can point a telescope at the sky. There is no way that people can be organized enough to hide something like this. And as soon as we think When something unusual happened, we followed up. We wanted to know more about it. 

So that's fine, there are still no super civilizations, but maybe, someday, we will really receive a signal or see something there that has to be artificial. And then I'll be in my backyard with that telescope, looking with goosebumps.

~sciencefreak