14 Minutes of Mind Blowing Space Facts With Astrophysicist Brian Cox

there are 2 trillion galaxies in the observable universe you need to know that the Milky Way galaxy has got 200 billion stars most of those stars now we know have planetary systems we estimate there are something like 20 billion earth-like planets or potentially earth-like planets in the Milky Way galaxy alone. so if you're asking questions about what is my place in the universe you need to know those things first of all. it's framework within which you can think. I've been doing some work on black holes and there's progress being made on that now which think is profound and exciting. so they are stars at the end of their life Bigger Than The Sun more massive than the Sun but they run out of their fuel and they start to collapse because gravity squashes them and if they're sufficiently massive then there's nothing that can stop the collapse and so they collapse as far as we know to point and essentially an infinitely dense point, but they collapse to such an extent that there's region around it where from which light can't escape. so nothing can escape and that that's black hole they they're surrounded this region where if you fall in It's called The Event Horizon and if you go across that Horizon then you are going to the center there's one way of thinking about it which is quite cool which is that the time and space sort of flip is one way to think about it so in the same way that we are going into the future now so we're going to tomorrow there's nothing we can do about it we are going to tomorrow in the same way if you fall in across the Event Horizon of black hole you are going to the middle The Singularity it's called so that's that's your future every line of your future points to the center of the black hole. we have now got photographs of them so we have two photographs which are radio telescope photographs one of the the one in the center of our Galaxy which is little one it's called Sagittarius star so it's about 6 million times the mass of the Sun and they took photo of one in the Galaxy m87. 55 million light years away that thing is around 6 billion times the mass of the Sun so if you took our sun we you can fit million Earths inside and collapsed it down to make black hole it would form black hole when it shrunk. so you squash it down till it's about 2 miles and then that would form black hole. 6 billion times the mass of the Sun means you multiply that by 6 billion so these things that the so called Schwarzschild radius is larger than our solar system. so what what you're seeing there is the emission from the material that's swelling around it it's called the accretion disc so you have material that's orbiting very fast emitting lot of radiation and that's what you see. it's flat disc by the way think Saturn's rings so this material is very flat but what you're seeing in that photograph is the light rays being bent around the black hole from that flat disc so that was prediction from Einstein's theory basically published it in 1915. and you can predict that that's one what one should look like and then just about was at 4 years ago now maybe five years ago, for the first time in history we get an image of one and it looks like the prediction. in science at the moment space science we have this debate lot actually because of course space probes like curiosity that's on Mars at the moment that's really cheap compared to sending people to Mars and so quite often the scientists who want to find out about the worlds will say well we should spend it on robots we shouldn't spend it on people think crude space exploration is in in some ways mean it's clearly true at the moment that humans can do more than robots so we can explore the place better it's about living and working off the planet which think is quite persuasive argument actually we we've already industrialized near Earth orbit so it's already multi-billion dollar industry you know communication satellites and weather satellites GPS whatever you we're already up there and so learning to live and work in space is think natural extension of our of our civilization plus the fact if you talk to Elon or Jeff Bezos they point out that the amount of resources available just slightly above our heads is vest and so remember talked to Jeff Bas actually once and he he thinks really simply and he said know for example in the asteroid belt there's enough metal think to build skyscraper what is it something like 800 stories tall and cover the Earth in it right if you want. now we don't want to do that but his point was that that the energy from the Sun is all up there the resources are up there so you could almost imagine trying to Zone the Earth residential at some point in the future to protect the planet and do your heavy industry off the planet for example and these sound it sounds like science fiction except that now SpaceX and Blue Origin those people have got reusable Rockets so suddenly the economics become sensible. think expansion is good and think we will expand and think we will expand outwards because there's not much room left on this planet to expand that's whole different idea it's not about Gathering scientific information it's about frontier and all the benefits that come from operating as civilization on frontier which we have lost on the earth because there is no Frontier left and so like that idea so there there is no other planet we can go to other than Mars you can't go to Jupiter or Saturn you can't go to Mercury or Venus so if we want to go go somewhere and expand our civilization it has to be Mars and everything's there that you need it's interesting actually because we know something about the history of Mars now quite lot about the history of Mars and it's certainly clear that there was water almost certainly oceans rivers so and that water is almost certainly still there so there's certainly ice there may even be pockets of liquid water below the surface somewhere so couple that with all the the minerals and the resources that we know are there and you have everything you need so that's the thing about Mars it's quite nice relative to everywhere else other than the earth you can't go to Venus you'd just melt it's what is it 400 and something degrees and 90 atmospheric pressure so Mars is quite nice think there must be even in the solar system would not be surprised if we find microbes on mars or on some of the moons of Jupiter or Saturn where there's liquid water and the reason is if you think about the reason think that and it's guess is because if you look at the history of life on Earth so Earth formed there was no life it was ball of rock and almost as soon as it cooled down we see evidence of life so certainly 3.8 billion years ago possibly even further back than that we see evidence of life on Earth. so somewhere along the line geochemistry active geochemistry became biochemistry on Earth. and we have some idea you know that that if you get gradients of temperature and acid and alkaline and the conditions that are naturally present on the surface of oceans, then complex carbon chemistry spontaneously happens. so we have we know that life almost certainly we know that life began on Earth mean the other option is it came from space or something like that but it probably didn't right probably began on Earth so that means that at least here that happened and that we know that the conditions that led to the origin of life on Earth were present on Mars 3.8 4 billion years ago and we know that they're present on Europa today so don't see that there's anything special life is just chemistry the idea that geochemistry becomes biochemistry is not fanciful because it happened here so think that given the same conditions it would be surprising to me if the same thing didn't happen in that life begins to test that is one of the great frontiers of science now it's one of the great challenges which is why another reason we're interested in Mars because we know those conditions were there we know there were what's called hydrothermal vent systems on the floors of oceans on Mars 3.8 or 4 billion years ago so it would be good to know what I've said is right and the way we find out is to find life or evidence of past life. you know that there's thing there's theory called the Grand Tack Theory so it's very hard to explain the evolution of our solar system when you do computer models of solar systems you don't tend to get four Rock planets to close to the Sun and four big gas giants further out and one of the current best theories and this say this because it shows you how looky we might be is that Jupiter they tend to form these big gas giants and migrate inwards towards the star so in almost all the computer simulations just because you got this big gas giant orbiting in all the dust around the star they tend to drop inwards and it looks like Jupiter did that so it looks like it formed and came in and came in almost to where Mars orbits today and and cleared out the region around Mars actually which is maybe the reason Mars is so small compared to the other to Venus and Earth but then Saturn was coming in as well and in the computer models the interaction between Jupiter and Saturn stops Jupiter coming in before it gets to the Earth and they both get dragged out again and so to where they are today wow and so that and that that seems to be it's one of the best theories for the evolution of our solar system. so what are the chances you know the the chances of that are so minuscule tiny so that's the thing think about these rocky planets you in order to get civilization on them think you need guess you need quite unusual solar systems and that would be guess and you need quite unusual stability on the planet for for billions of years and that's why think we might be quite lucky. an answer would be we are small finite beings right which are just clusters of atoms as we said before they're very rare but we understand roughly how they how they came to be and we have limited amount of time not actually unfortunately but because of the laws of nature the laws of nature forbid us to be Immortal immortality is ruled out by the laws of physics but also what's interesting about if you look at the basic physics of the universe going from The Big Bang to where we are today then the physics is driven by the fact that the Universe began in an extremely ordered state so it was very highly ordered system and it is tending towards more disordered system at the moment and that's called the second law of thermodynamics. what we strongly suspect and and would say no is that in that process of going from order to disorder complexity emerges naturally for brief period of time so it's natural part of the evolution of the universe that you get period in time when there's complexity in the universe so stars and planets and galaxies and life and civilizations but they are they exist because the universe is decaying not in spite of the fact the universe is decaying so our existence in that sort of picture is necessarily finite and necessarily time limited and it is remarkable thing that that complexity has got so far that there are things in the universe that can think and feel and explore it. and think that is the answer if you want an answer to the meaning of it all is that that you are part of the universe because of the way the laws of nature work you are allowed to exist but you're allowed to exist for temporary for small amount of time in possibly infinite Universe what more do you want you know when when see people who go want want more than that want more you know must there must be more to it what do you mean the ingredients in our bodies were assembled in the hearts of long dead stars over billions of years and have assembled themselves spontaneously into temporary structures that can think can feel and explore and then those structures will Decay away again at some point and in the very far future there'll be no structures left so so there we are we exist in this little window when we can observe This Magnificent Universe why do you want any more