22 Jul 09
Originally posted by joe beyserYou mean are distant galaxies are moving away from us but NOT because space is expanding?
Could it be that the astronomers have it wrong? What if there is no expansion of space. Instead of one big bang maybe there were many smaller bangs and they formed the galaxies. I do know that in every direction the distant galaxies are moving away from us, but we are not the center of the universe. That gives expanding space some creedence.
If yes, I wouldn’t totally rule out that possibility although I don’t see how that wouldn’t help explain any of the current astronomical observations and it probably would require a serious rethink on Einstein’s general relativity and whether what it implies about gravity and curvature of space over large distances is in fact wrong!
-I am guessing it is unlikely but I am no expert.
22 Jul 09
Originally posted by KazetNagorraWhat if the background radiation from this one big bang actually overlaps the others?
Well, if there were multiple big bangs it would sure be strange that we can see background radiation consistent with one big bang.
I'm not sure that makes sense, since I don't know much about the topic.
23 Jul 09
Originally posted by Andrew HamiltonI was just thinking of a possibility where space itself isn't expanding except for the fact things at a certain distance move away from each other causing there to be more space between them. Expanding space looks to be the explanation. Close galaxies actually collide when they are close enough, but the far away ones seem to move away. When the universe was formed and galaxies were beggining it seems strange that it took 13 billion light years for the light to get here when the beggining of the universe was only 700 million years prior to galaxie they discovered. Granted, we are moving away from it at a fast pace as indicated by the shift in light frequency, but that shows we are not moving faster than light. If expanding space is the explanation then how come they can use the inverse square law and relative brightness to determine distance.
You mean are distant galaxies are moving away from us but NOT because space is expanding?
If yes, I wouldn’t totally rule out that possibility although I don’t see how that wouldn’t help explain any of the current astronomical observations and it probably would require a serious rethink on Einstein’s general relativity and whether what it implies ab ...[text shortened]... space over large distances is in fact wrong!
-I am guessing it is unlikely but I am no expert.
23 Jul 09
1 edit
Originally posted by joe beyser…If expanding space is the explanation then how come they can use the inverse square law and relative brightness to determine distance.
I was just thinking of a possibility where space itself isn't expanding except for the fact things at a certain distance move away from each other causing there to be more space between them. Expanding space looks to be the explanation. Close galaxies actually collide when they are close enough, but the far away ones seem to move away. When the universe w ...[text shortened]... hen how come they can use the inverse square law and relative brightness to determine distance.
….
They don’t only use these things.
They use the Doppler shift (which they have to take into account anyway if they are to also use the inverse square law) which gives the speed (which gives a clue about distance by extrapolating that to see how it relates to the expansion of the universe) and clues such as the apparent diameter of the galaxies as well as their relative brightness but taking the Doppler shift into account to interpret the relative brightness because objects moving away from us will appear less bright because of the red-shift.