The Royal Institution: The Other End of a Black Hole (James Beacham)
On a different yet still recent enough thread, I wrote...
Quote:
Originally posted by
Aragorn
Well, the thing with the Big Bang is that 99.9% of the people misunderstand what it really was. It was not the universe suddenly exploding out of a single point, because if that were the case, then there would be a discernible "center of the universe", and there isn't. The universe keeps on expanding (and at an accelerating rate) in all directions.
So rather than a "bang", the Big Bang was simply the moment that the universe whisked into existence. And while it did know an accelerated expansion during the first phases of its life, it then slowed down a great deal in its expansion, but it still keeps on expanding, and the farthest-away-from us part of the universe is expanding faster than the regions closer to us. Also, those far-away regions are expanding much faster than the speed of light, albeit that this is not a violation of Einstein's relativity theory, because it is spacetime itself that's moving faster than the speed of light, not the objects within spacetime.
Therefore, all things considered, one could posit that the whole universe is in fact behaving like an inside-out black hole. The escape velocity of a black hole is greater than the speed of light, and thus, no light can ever escape from within a black hole — hence why it is termed "black". And as the universe keeps on expanding and the velocity of this expansion is higher than the speed of light, the light emanated from those remnants of the Big Bang can never reach us, just as the light emanated by a black hole can also never reach us. As such, both a black hole and the circumference of the observable universe have a for our human senses impenetrable event horizon — our eyes will never be able to see what's beyond that event horizon.
This presentation below addresses the fact that the math does indeed suggest that our observable universe would be the inside of a black hole. The presenter is also very witty and addresses some aspects of society.
The lecture itself is 58 minutes in length, and the Q&A video below is 28 minutes in length. Enjoy!;)