Big Bang, the start of the universe, and CMBR
Discussion
Forgive my non-physicist questions on this, but we keep hearing that before the BB the universe was compressed into a tiny area. Where was that area? If we can observe galaxy GNZ11 13.8 billion light years away, and that galaxy was formed relatively shortly after BB, and the light from that galaxy is red-shifted, so it is travelling away from us, and presumably also away from the site of the BB, does that mean that the BB happened in between us, and that galaxy?
If we look at galaxies diametrically opposite the GNZ11 from our perspective, are they moving less quickly away from us because we and they are moving away from the BB site in the same direction?
And, and, this Cosmic Microwave Background Radiation, said to be an echo of the BB, why hadn’t it overtaken us and vanished by now? Radiation must travel faster than galaxies. If I am a duck on a pond and someone throws a pebble in, the ripples radiate out and go past me. They don’t hang around to be measured years later.
Thanks.
louiechevy said:
There is no spot nowhere existed until the big bang happened and expanded into the universe, so everywhere you look is where the big bang happened thats also why we can still detect the background radiation as its all around us.
Cheers. On delving it seems most believe it was a big stretch rather than a Big Bang in the sense of an explosion. There does seem to be uncertainty as to whether the universe is finite, or infinite. If it is finite, you would expect it to have a centre of mass, which you might consider the centre of the universe and so the very small dense thing that expanded might have ‘been’ there; on the other hand, the universe may be infinite, with no centre of mass, but in that case why does the night sky look mostly black (infinite number of stars = light universe).....eharding said:
Excellent! She must have read my mind. louiechevy said:
With the light most of the stars even in this galaxy are so far away that the light can't get to our eyes because its blocked by all the gas and other things in its way, imagine standing in a wood you could see someone stood next to you but as they walked away all the trees would hide them from your view.
If the inverse is infinite, how can it have been made only 13.8 billion years ago? That is not enough time, even at light speed, to expand to infinity. If it is not infinite, it must have a centre of mass, no ?
Great, cheers.
A follow-up. We hear that prior to Big Bang the entire universe existed in a dense body smaller than an atom.
Why does it have to be so small? Why cannot it have been say apple-sized, basketball sized or planet-sized, which would also make it unbelievably dense, but more analogous to a super black hole.
A follow-up. We hear that prior to Big Bang the entire universe existed in a dense body smaller than an atom.
Why does it have to be so small? Why cannot it have been say apple-sized, basketball sized or planet-sized, which would also make it unbelievably dense, but more analogous to a super black hole.
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