it's a triple no quadruple system so aliens so we're looking for aliens on the surface of Mars now there's a robot called perseverance which is on an ancient river Delta in what we know is an ancient Lake and it's drilling down to take samples to try and find evidence that life existed there because there was water and all the things that we think are necessary for life so I wouldn't be surprised if there are aliens on Mars right martial microbes we've got one called Europa Clipper they're going to launch to Jupiter's moon Europa that's a
frozen Moon about the same size as our moon but it's ice the whole surface is ice and below the surface there's more there's water salt water sodium chloride in the water and there's more water in there than all the oceans of the earth combined about three times as much and so that's a candidate for life and so we're sending a spacecraft to look for life so it's not Bonkers to suggest that life may have begun somewhere else other than earth right that we're looking for in the solar system but what is really worrying observation to
me actually is that we've looked to be it for radio signals and we look out for signs of anything out there in our galaxy intelligence and we don't see anything at all and astronomers call it the great silence it's kind of an ominous name because it seems there's so many planets 20 billion potentially earth-like planets in the Milky Way you think there's loads of room and there's loads of time so there should be things out there but we don't see anything and the explanation probably if indeed that's true is biology it's just if you look
at the history of life on Earth it took nearly 4 billion years from the first cell to a civilization four billion years nearly that's the third of the age of the Universe I think the guess the best guess is that we're so incredibly fortunate to be here because it's just that ask that you say I want a planet to support an unbroken chain of life through all this violence in the universe an unbroken chain of life for four billion years in order to get to something like you and me Collections of atoms that can think
I think it's just really unlikely it's terrifying and also kind of uplifting in a way isn't it because it means that we're unbelievably valuable as a species and a planet it could be we're the only island of meaning in an ocean of 400 billion Suns foreign the search for extraterrestrial life has captivated human imagination for centuries from ancient mythology to modern science we've always looked up at the stars and wondered are we alone with technological advancements our ability to explore the universe has increased and the possibility of finding alien life seems closer than ever before
but despite years of searching we have yet to discover a definitive proof of life beyond Earth however recent discoveries of exoplanets some of which are potentially habitable offer tantalizing hints that we may not be alone after all you go back you know 15 years or so 20 years we only knew with our solar system so it's possible to believe but all those stars in the sky were just Stars we didn't know but now we've discovered over a thousand planets out there around Stars the remarkable thing the Kepler has been looking just a little piece of
Sky to do a kind of a survey a tiny piece of sky and it found six earth-like planets these are rocky planets in the right Zone around the star so the temperature is right so there could be oceans and rivers and if you just then extend that over the entire Sky the number now people are talking about is 20 billion earth-like planets that could have a life in the Milky Way twenty thousand million other Earths despite the discovery of many Earth-like planets in the Milky Way we have yet to find any definitive evidence of alien
life some theories suggest that we may not be looking in the right places or that the conditions for life are more complex than we originally thought others speculate that intelligent civilizations may be intentionally avoiding contact with us when the realization sets in that there are close to infinite alien worlds with conditions similar to Earth it's hard to Fathom but not even one other civilization's signature has been detected this Enigma remains one of the greatest Mysteries of the cosmos leaving us Yearning For answers this has got a name called the Fermi Paradox after the physicist Enrico
Fermi because now you know 20 billion Earths the galaxy has been around for almost the entire age of the universe 13 billion years why we haven't seen evidence of another civilization the Fermi Paradox questions the absence of extraterrestrial life despite the vastness of the universe and the septillions of stars in it the great filter hypothesis suggests that there is a barrier that prevents civilizations from advancing past a certain point causing them to become extinct but what if the barrier is ahead of us this brings us to the Dark Forest hypothesis which persists that intelligent civilizations
remain silent and hidden much like animals in a dark forest for fear of being discovered and eliminated by other more powerful and advanced civilizations this chilling possibility forces us to consider the perhaps the universe is not the welcoming place we may have thought it was the Dark Forest hypothesis proposes that intelligent civilizations are engaged in a cosmic game of hide and seek where every civilization is both the seeker and the Haider in this game revealing oneself could lead to the destruction of the civilization by other more advanced civilizations therefore staying silent and hidden is the
most logical and safe option this hypothesis suggests that the universe is not a friendly place but rather a place where every civilization is competing for resources and survival it implies that the reason we have not yet discovered any extraterrestrial life is that every civilization is hiding in a cosmic Dark Forest but maybe we are getting ahead of ourselves and life is far more ubiquitous and less mysterious than we think at least as far as simple forms of life goes such as microbes I wouldn't be surprised find that life had existed on Mars perhaps even still
May subsurface but I would be very surprised there were anything other than single-celled at best but the question is about aliens about civilizations we don't know we've looked a bit we have the seti program we've heard nothing astronomers have a term for it they call it the great silence but it is possible the biologists I talk to to tend to say you look at the history of life on Earth then it seems clear that for around let's say three billion years or so after the origin of life around 3.8 billion years ago up to less
than a billion years ago it was single cell and complex multicellular life is a relatively recent development so on Earth we had about four billion years to go from the origin of life to a civilization and if that is in any way typical and we don't know then the astronomers will tell you that perhaps there aren't so many worlds that have stayed stable enough for long enough for that process to continue we don't know there's a key Point here that it is at least conceivable that worlds like this are very rare in the sense that
there's complex a very complex ecosystem of civilizations and intelligence you can make an argument that there could be on average one per Galaxy but what if there is more than just one civilization per Galaxy the possibility of multiple intelligent civilizations existing in our galaxy opens up a whole new realm of possibilities what if they are trying to contact us but we're not listening one solution to the Fermi Paradox suggests that the lack of evidence of extraterrestrial life is due to the vast distances between civilizations but what if we're just not paying attention the wow signal
is a prime example of a potential contact from another civilization that we may have missed a radio telescope called the big ear detected a radio signal from somewhere in the vicinity of the constellation Sagittarius and this is the printout from that night it was a pulse the peak brightness was over 30 times the brightness of the background radio emission from the Galaxy that's the wavelength of light of radio waves emitted from hydrogen atoms so the whole Sky glows at that wavelength and back in the 1950s radio astronomers speculated that if an alien civilization wanted to
communicate with us and they might well choose that very special natural wavelength to send their message so surprising was this that when it was spotted a few days later by an astronomer called Jerry Ayman he circled the pulse a 72 second flash of radio waves and wrote wow next to it so this has become known as the wow signal blink and you might miss it but the universe is constantly sending signals our way from the hum of stars to the crackle of black holes we're surrounded by electromagnetic activity but what if some of those signals
weren't just random Cosmic noise what if they were messages from intelligent civilizations far beyond our own that's the question at the heart of the Breakthrough listen initiative a team of scientists using AI to search for techno signatures from other planets in our galaxy it's not an easy task the universe is a chaotic noisy place and separating out potential alien signals from all the other background noise is like finding a needle in a cosmic Haystack but that's where AI comes in by training machines to recognize patterns we can sift through vast amounts of data in search
of that elusive extraterrestrial message and it's working in fact the latest breakthrough comes from a student at the University of Toronto who developed a machine learning algorithm that can filter out the most promising techno signature candidates just recently the algorithm detected eight very suspicious radio signals opening up a whole new realm of possibilities in the search for alien life as we continue to search the skies listen for the faintest whisper of alien technology one thing becomes clear the universe is vast mysterious and full of surprises who knows what other secrets are waiting to be uncovered
so keep your ears open and your mind even more so because the next message we receive might just change everything we think we know about the cosmos [Music] foreign
