This isn't a new idea. It's been kicking around for some time (at least two decades), rather hard to prove/disprove since there's no currently known mechanism, even theoretical, for observing what might have happened befoee the big bang.
Roger Penrose claims our Universe has been through multiple Big Bangs
171–180 of 248 posts
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#172The concept of infinity seems impossible to me in physical world. It's a great mathematical concept to model our understanding. Just like imaginary numbers. I cannot imagine anything being infinite in the physical world. I find the simulation hypothesis more probable than Universe being infinite. Space and Time is not infinite. It may be Gazillions of centuries old, but not infinity. It can't be.
But it can’t NOT be infinite! If space were three dimensionally finite, then there must be a boundary. But if there were a boundary, then there must be something beyond that boundary. And now we have a paradox that infinitely regresses. Same goes for time. Same goes for distance. How can there be both a finite distance, as well as an infinite number of points between two distinct points? To me, infinity seems to be e…
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Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#173The concept of infinity seems impossible to me in physical world. It's a great mathematical concept to model our understanding. Just like imaginary numbers. I cannot imagine anything being infinite in the physical world. I find the simulation hypothesis more probable than Universe being infinite. Space and Time is not infinite. It may be Gazillions of centuries old, but not infinity. It can't be.
But it can’t NOT be infinite! If space were three dimensionally finite, then there must be a boundary. But if there were a boundary, then there must be something beyond that boundary. And now we have a paradox that infinitely regresses. Same goes for time. Same goes for distance. How can there be both a finite distance, as well as an infinite number of points between two distinct points? To me, infinity seems to be e…
> If space were three dimensionally finite, then there must be a boundary.
Not true, space might just repeat in all directions - a finite volume but with no boundaries. Maybe if you go far enough you always end up back where you came from.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#174Earlier quoted context omitted.
Yea, that is my understanding. He does call it a crazy theory, but its a whole different kind of crazy that most people think of. I've listened to him talk about it and yea, when you actually listen to him you get the vibe of, "its an interesting idea that the math can't really prove or disprove, it may not be right, but it is an interesting thought experiment." I would say it is a step below Fred Hoyle. For those wh…
Should we entertain unfalsifiable theories?
If you don't peddle it as the real solution with zero evidence or as anything other than an interesting thought experiment, why not? He's not starting a cult based on multiple big bangs. I think it's fine.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#175The concept of infinity seems impossible to me in physical world. It's a great mathematical concept to model our understanding. Just like imaginary numbers. I cannot imagine anything being infinite in the physical world. I find the simulation hypothesis more probable than Universe being infinite. Space and Time is not infinite. It may be Gazillions of centuries old, but not infinity. It can't be.
That seems to be a personal problem. There's nothing inconsistent about either space or time being infinite.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#176I've always liked the theory that every black hole has a white hole on the other "side" that spews out a universe from the information it collects. And the original black/white hole? Well, something something quantum fluctuation something out of nothing.
That’s almost the basis of the concept of Cosmological Natural Selection, which was taken seriously by many credible physicists. It’s fallen out of favor due to the consensus on the Black Hole Information Paradox veering towards information preservation. But it’s still an interesting idea.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#177This isn't a new idea. It's been kicking around for some time (at least two decades), rather hard to prove/disprove since there's no currently known mechanism, even theoretical, for observing what might have happened befoee the big bang.
That isn't entirely true. As the article discusses, under the proposed conformal cyclic cosmology, gravitational waves would leave a lasting effect visible between aeons. This effect would be visible in the CMB, and some researchers (including Penrose) claim to have found such a signature in their analysis of the CMB. The validity of their analysis is still in dispute (because detecting such a signal from the noise of the CMB is a very hard problem), but in principle the signal would be there if CCC is correct.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#178Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#179No offence, but Sir Penrose has been claiming a lot of very unlikely things the last couple of years without any evidence. Which is fine, philosophy is important, but let’s not put his statements in the realm of actual science.
Re: Roger Penrose claims our Universe has been through multiple Big Bangs
#180Interesting to note that the idea of the "Big Bounce" has been around a long time. Penrose's claim seems to be that there may be evidence of it in cosmic background radiation hotspots. This was Nietzsche in 1885, musing on how developments in thermodynamics had complicated the mechanistic picture of the universe: > And do you know what "the world" is to me? Shall I show it to you in my mirror? This world: a monster o…
Penrose's theory of conformal cyclic cosmology is distinct from the big bounce theory. In the big bounce theory, the universe reaches a point where expansion slows down and eventually reverses into contraction. Then, eventually the universe reaches a high enough density where something happens and it begins expanding again in a new big bang.
In conformal cyclic cosmology, the expansion never reverses. Instead, there is a bit of a mathematical trick. If you assume that all massive particles eventually decay, then at some point the universe will contain only massless particles which travel at the speed of light. In such a universe, scale becomes meaningless. That is to say, if you take a region of space that is 1 light year across and watch it evolve for 1 year; that is indistinguishable from a region that is 1 light second across evolving for 1 second. Taking this to the extreme, such a universe that is infinitely sparse is indistinguishable from one that is infinitely dense. In other words the state of our universe after infinite time is mathematically indistinguishable from the universe at the big bang. Of course, after applying that transformation, you would again see a universe with an infinite future that is also equivalent to the big bang, so you can apply the same transformation again.