Railton2 Posted February 24, 2011 Posted February 24, 2011 I am not sure where to post this thread. Sorry if it is the wrong place. If it is, please move it to the correct forum, thanks in advance Hey How come our universe still exists? According to what I know our universe was created from a singularity, the big bang, a so called explosion. If everything, including all matter and energy, was created at the time of the big bang, then all matter must have been squeezed together in the first nanoseconds of our universe. How come that there wasn't a black hole, when all the matter from our universe was squeezed into that small place in the first second? If there was a black hole, how come our universe still exists? According to what I know, the definition of a black hole is an object so dense, that the gravity is so powerful, that not even light can escape. That means in order for matter to escape from the event horizon created by a black hole, then the matter MUST exceed the speed of light. According to Einstein's theory of relativity; In order for matter to travel faster than the speed of light, then you must need more than an infinity amount of energy. Then how come that the matter escaped from the event horizon at the beginning? All matter in our universe MUST have travelled faster than the speed of light in order to escape it. Does that mean that all the matter in our universe had more than an infinity amount of energy in the beginning, in order to escape? Why didn't the universe collapse by its own gravity, without using an infinitive amount of energy for the matter to escape? If there wasn't an infinity amount of energy at that time, then our universe must have collapsed by its own gravity or what? How come our universe still exists? Did our universe collapse by it's own gravity? Could our universe be a black hole? Thanks for reading, I really hope you understand and will answer my questions Sincerely, Mark Have a great day!
IM Egdall Posted February 24, 2011 Posted February 24, 2011 (edited) A black hole and the big bang are not the same. I read somewhere that a black hole is a singularity in space extending through time. And the big bang was a singularity in time extending through all space. Think about that mind-twister! So the big bang is not just a single location in space; it is space itself which is contacted. And then space expanded, taking the particles (matter and energy fields) with it. And per special relativity, nothing can travel faster than the speed of light through space. But per general relativty, space itself can (and does) expand faster than the speed of light. And remember, the so-called singularity is really a problem. Here all known physics breaks down. So no one knows whether there really was a singularity of infinite density and infinite temperature at the big bang. I think most physicists doubt this description. So what was it really like at exactly time zero of the big bang.? Again, nobody knows. And no one knows what it is really like at the very center of a black hole. Physicists hope that by somehow combining quantum mechanics and general relativity into some new "quantum gravity" theory, it might tell us what is really going on in these instances. Let's hope so. I found a link that might help: http://www.phys.ncku...s/universe.html Edited February 24, 2011 by I ME
Airbrush Posted February 28, 2011 Posted February 28, 2011 (edited) Nice explanation I ME. I had also wondered about that. From your excellent link: "The short answer [why the universe did not become a black hole at the start] is that the Big Bang gets away with it because it is expanding rapidly near the beginning and the rate of expansion is slowing down. Space can be flat even when spacetime is not." http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/BlackHoles/universe.html In other words, the universe was never static at the beginning. It was always expanding faster than light. Now that is hard to figure. The big bang never existed UNTIL it was expanding faster than light. Edited February 28, 2011 by Airbrush
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