Where Are All The Aliens? | Tim O'Brien | TEDxOldham

I think I also saw an interesting question:

where

were all the

aliens

? Could it be that I am a scientist? I'm not crazy, but I actually think maybe there are

aliens

available. I want to convince you that this is worth it. It's a scientific question to ask, but I think first of all we need to appreciate how big space is. I think the best answer I heard in Douglas Adams' Hitchhiker's Guide to the Galaxy was that space was big, very big, extremely big. We really don't know. I don't know, I don't know how big it is, but let's have guts, we might have a small chance of understanding that this is the Sun, even occasionally seen from here in Manchester, but the Sun is about 150 million kilometers away, which It's a little hard to imagine.

The Earth is about twelve thousand kilometers in diameter, so 150 million kilometers is a large distance. One of the things we tend to do is think about how long it would take us to get some

where

if we were traveling at a certain speed, so in this case it's as fast as we can. The trip is the speed of light, so it's about 300,000 kilometers per second and at that speed you would reach the Sun in about eight minutes. In fact, when you look at the Sun, it takes eight minutes for the light to reach you, which is what you know.

Sort of the amount of time you spend here listening to a portion of all this talk or not too much, but space is obviously bigger than that if we go out to our galaxy, the Milky Way, our galaxy, the Milky Way, has many suns, many stars, hundreds of billions of stars, so if we shared all the stars in the Milky Way among all the people on Earth, we would all get about 50 base plates H, that many stars in our galaxy, the Milky Way , and the other closest star. to the Sun that light that took eight minutes to get to us from the Sun is on its way now when I started to talk some lights fired from the Sun and then it will get there about half way it will get here about half way through this talk if that The lights pass through the Earth and we have waited for that light to reach the other closest star.

We'd be sitting here listening to my talk for about four years, so it's probably not the best thing to do at such great distances between Earth. stars and in our entire galaxy, the Milky Way, that it would take that light a hundred thousand years to cross it with those hundreds of millions of stars within it, in reality that image there is a galaxy, it is not our galaxy, it is the great galaxy closest spiral to ours is called the Andromeda galaxy, so it's the closest other large galaxy, like the Milky Way, and the light from those stars that you see in that image, you can actually see this, if you know where to look , you can look, you see the center. of this galaxy with the naked eye you don't even need a telescope, a small blurry spot that the light that you can see from the center of that galaxy takes two and a half million years to reach us, so you can go back in time two and half.

Half a million years ago when you look at a galaxy like this, then space is big and this is just the nearest other galaxy. What if we talk about life and wonder where the aliens were that we probably need to ask? were the planets that we know, so far we only know one example of life, life here on this planet, so we know there are many stars, we can see them shining in the night sky, but it is very difficult to see the planets, so these stars They do this? Hundreds of millions of stars have planets orbiting them, and we are living in a very special time right now.

Actually, about twenty years ago we found the first planet orbiting another star like the Sun. I looked up what the number was yesterday. and the number is now 1642 confirmed planets, all among all the stars, so those are just the ones we found by extrapolating that to all the stars in our Milky Way, where we know there are billions and billions of planets in our Milky Way Milky, where practically all the stars you see. the night sky the night sky will be orbited by planets, of course, you may wonder if those planets have life on them and one of the key things is whether they are too close to their star to be too hot, for example.

Liquid water is something we believe is key to life here on Earth, the only example we have. If you were too close to your child, it would be too hot for water to evaporate if you were too far from your star. your Sun then you would discover that that water would freeze and then you would not have the liquid water that we believe would be essential for all the biochemistry of salt to work that maintains us and that allows us to be alive to allow the lowest life. Outside of life on Earth again, looking at what we found in our Milky Way along with these, you know, 1000 confirmed planets, so far we know that there must be billions of so-called habitable planets in our Milky Way galaxy alone. , not in the Andromeda galaxy they want.

To show you this other galaxy and not in the 100 billion other galaxies that we can see in the observable universe, in ours alone there must be billions of habitable planets, potentially habitable planets, in other words, those that are not too close from the star it's not very hot it's not very far it's not that cold so they have liquid water now aliens have visited the Earth who believes that aliens have visited the Earth or no one dares to raise their hands okay, there are quite a few people around the planet that I think aliens visit Earth and visit it all the time and actually claimed to have met them, but I don't think there's actually a lot of solid evidence for that, but it's an interesting question.

Know? Could they have done it? We've only You know we've only been around for a long time. You know modern humans haven't been around that long in terms of the planet's history, only a few hundred thousand years, so my aliens visited Earth at some point. Well, here's an interesting thing to think about and it's something we could do in the future, which is to send out a fleet of what are called von Neumann probes, your space probes that you send out and they go out and search around other stars to see. what they can find around other stars, we just discussed the fact that these stars are very far away, even light takes four years to reach the nearest other star and we can't make things travel at the speed of light , the fastest spacecraft travels at something like 60,000 kilometers per hour - all that kind of speed, a small fraction of the speed of light, so imagine that sending one of these space probes is traveling at a fraction of the speed of light, that is the speed of salt that we can, we can say. things in the Mormon, it would take, you know, maybe 50,000 or 100,000 years to get to the nearest star, but when it gets there, what it does is it replicates itself, so it gets there and maybe along the way it gathers material from where you collect material. things between the stars maybe when it gets to the planet around one of those stars and gathers more material and builds a copy of itself and then actually those spaceships leave again and head in different directions and go to the next of the stars and when they get there, each one of them self-replicates and sends itself again.

This doesn't sound like science fiction at all, but in fact it's possible to imagine that we could do this in the not-too-distant future again and again. If you calculate how long this process takes, you can calculate how long this process would take. In reality, you could explore the entire galaxy in less than 100 million years. To an astronomer, that sounds pretty fast because the Earth is about five billion years old, four and a half billion years old, because in five hundred million years this was less than 100 million years. You can speed it up by making multiple copies or making them travel a little faster, so this is really short in the lifespan of a planet like Earth or in the lifespan of the stars that are in the galaxy, so if you imagine that there could be life beneath these other planets that could be doing this, an interesting question is whether aliens had there been a civilization before us that could do this.

If we've done this, we may have actually been visited by these fleets of probably self-replicating robotic spaceships spanning across the galaxy. We don't see, we haven't seen any evidence of that, but it's an interesting question that we haven't been here to answer. A long time ago in the history of the Earth it is something we should be looking for. It is called the Fermi Paradox. If aliens exist, where are they? because actually this is not too popular in the galaxy so how are we going to look for life? on other planets, well, one of the ways to look for intelligent life and here I am only going to talk about intelligent life and that is because we know that in the history of life on Earth most of that time life was bacterial , so they are basically microbes. for billions of years before it evolved into something complicated like plants or animals or even intelligent life like us, so it may well be that bacterial life is common, but if we were interested in intelligent life, you'd want to have a conversation with some of these aliens.

One of the ways we could do this is by using a radio telescope. This is the one at the Georgia Bank where I work, the Louisville telescope, and this is just a recording of the solar signal that we captured with that telescope. Obviously, Rebe, a problem arises when searching for the cells there, but maybe you'll get a little bored, it just sounds like a hiss, it's just noise that was actually read your way, in that case it was read your way and it came from a star that exploded in about the year 1670, as it happened, but you know.

You can't really hear much, it just sounds like noise. If you were hoping to pick up a signal from aliens, you're probably expecting something a little more complicated in that signal than just art than just that noise, and here's an example of something that was chosen. It came about not long after we started thinking about using large radio telescopes like the Louisville Telescope there at Jodrell, which was built in 1957, so in the 1960s we started using these telescopes to look for messages, maybe code-type messages. Morse buried it in that noise and just a few years later, in 1967, one of these signals was captured and here again is a recording made with our telescope pointing in a particular direction in the sky.

It's a surprise I'm used to hearing. the noise, the hiss, hearing what was seen, the regular flash of an object in the invisible sky would require surprise, in fact, that first object was discovered by Jocelyn Bell at the University of Cambridge in 1967, the first thing to be called a little green man , an lgm1 they called it because they thought you knew that this is possibly an extraterrestrial signal, actually we now know through the remains of stars that exploded, things called pulsars, very exotic objects that we use to test our understanding of physics and Einstein's theories of gravity, so maybe they aren't aliens. unfortunately but exciting for physics, although what do we do with other telescopes?

Well, we use telescopes like this. This is the Arecibo telescope. This is a huge radio telescope. The largest radio telescope in the world. It is in a valley in Puerto Rico. It is 300 meters in diameter. It makes it four times the size in diameter of the Jodrell Bank Level Telescope, a huge telescope that is used for many different things, but one of the things it does is a project called Serendip, which some of you may know from a SETI at home. , you can download a screen saver for your computer and it will basically process data looking for these types of extraterrestrial signals that are captured with a radio telescope like the one that another radio telescope around the world has done and is doing this type of work is the telescope Green Bank this is in West Virginia this telescope is about 100 meters in diameter these large telescopes pick up a lot of radio waves they say you're them if you want they hear very faint things coming from the distant universe and so these are the kind of things we could be interested in using to capture extraterrestrial signals and this has been used to search for those looks in the direction of those planets that we know from the Parkes telescope here in Australia again this telescope and the dollar telescope we participate in a new project in search of these extraterrestrial signals called innovative listening project our own telescopes you are in the UK we started a project with these telescopes a network of telescopes spread across the country between here and between Jodrell Bank and all the way to Cambridge, seven radio telescopes, all connected by optical fibres, linked together to act like a giant telescope, when again, among all the other things we are doing, we start looking at those signals for possible extraterrestrial signals and what is coming in the future.

The future is a telescopeamazing thing we designed right now, it's called the Square Kilometer Array, it will be built in southern Africa and Australia, it will be made up of hundreds of antennas connected to each other and other types of antennas connected to each other that will form a giant telescope. telescope whose size is equivalent to 220 times the size of the Jodrell Bank level telescope, will see incredibly faint things in the universe, will pick up incredibly weak signals, and in terms of searching for aliens, in just a minute, that telescope will be able to look. to look at each star in the direction it points about 300 light years away from us, so the closest star was four light years away, you will be able to go 300 light years away looking for each star in just one minute to find the There are types of strong signals coming from the radar systems that we use in our large telescopes, so if there are aliens with this type of technology and if there are messages, the signals coming out of this telescope will be an incredible facility for us. to be able to detect those signals, then I'm afraid I can't, what I can't do is give you the answer to my question: start, which is where all the aliens that we don't know, we haven't detected aliens anywhere, we believe that we do know that there are potentially habitable planets, that is a fact, we did not know it, 20 years ago we knew it.

Now that we have the technology, we will have the technology that will allow us to search larger and larger parts of our galaxy, looking for the types of signals from the technology that we produce, the radar systems that we use in airports and saw searching. these signals that could come from extraterrestrials and I hope that at some point in the not too distant future we will be able to answer the question of how we are alone in the universe. Thank you so much.