Our Universe Might Be in a Bubble | Brian Cox and Joe Rogan

When you get to those numbers when you're talking about trillions and billions and all those zeros My brain just goes numb. There's this Lack of comprehension that I'm well aware of like those numbers get thrown about I go. Oh 200 billion hmm I think everybody does I think every scientist that No scientist can picture that number. I mean he even the small number 200 billion The number of stars in one galaxy and then when you say two trillion galaxies You know that's I challenge anyone to be able to picture that but it is the reality that we've observed We've you know, we haven't counted all two trillion by the way We have we have a thing called the Sloan Digital Sky Survey which maps the positions of galaxies So you can you know how much of the sky you surveyed and you know How many galaxies you counted and then you can spread that across the wider universe and you get this picture of a vast and possibly Infinite universe we we know that the universe are very strongly suspect that the universe is much bigger than the piece we can see So we have good reason to think that's the case whether it's infinite or not is another question And then that goes to your you know that can you picture infinity? Well, no one can picture infinity There's a weird thing as well that you know, we say the universe began 13.8 billion years ago. So that's a measurement Because we can measure the speed that all the galaxies are flying away from us essentially And then you can run time backwards if you like to find out when they were all on top of each other And so it's a quite simple measurement and we've done that So we say the universe began 13.8 billion years ago But actually all we know really was the universe was very hot and very dense at that time And we have some theories that the universe was in existence before that and perhaps some sort of circumstantial evidence And that means that actually the universe could could have always been there eternal And then when I talk to people sometimes they get a bit Some people get upset about that. Some people would rather it had a beginning The idea that it might have been around forever is more frightening somehow than the fact that it began And it's it's interesting the way that people's minds Work what what terrifies you the most an eternal universe or a finite universe? Yeah, they're both incomprehensible the eternal universe If there was an eternal universe, is that negate the theory of the Big Bang or does it mean that there's a constant cycle of Big bangs and then Expansion and then recompression or it could do so those theories are back in Vogue some of those theories are back in vogue again. So yes, some of them say that there's a cycling universe so the Big Bang is an event when space gets very hot and very dense and filled with particles and That may happen again or some of the other theories There's a theory called eternal inflation, which is a theory that and it's actually the most popular theory I think at the moment, but what happened but why the Big Bang is the way that it is It's got some very special features of Big Bang which we could talk about but inflation is the idea that space Spacetime was around before the Big Bang and it was expanding extremely fast And there was doubling in size in the most popular of these theories every 10 to the minus 37 seconds Which is point not not not not not with 37 knots one of a second So it's an unimaginably fast expansion and then the idea is that draws to a close So quite naturally sort of dies away and the expansion slows down and all the energy that was taken It was causing that expansion sort of gets dumped into space and heats it up and makes particles And that's what we call the Big Bang and those theories that slight extension to those Say that that's slowing down just happens in little patches So most of the universe the overwhelming majority of the universe is still inflating at that insane Some speed and the just little patches stop and they're big bangs. So you get multiple Universe is a multiverse. It's called the inflationary multiverse and we are in one of those bubbles and that's one of the more popular theories