According to the most commonly accepted modern theories, (as far as I am aware), the observed red-shift in light from distant galaxies is blamed on the expansion of the universe, and the resulting movement of those galaxies away from us.
Has anyone explored the possibility that photons are not as completely stable as we think they are? Could the red-shift actually be due to photons losing energy when traveling such vast distances?
Are there other indicators of the movement of galaxies away from us other than just red-shift? For instance, as they move farther away, are they becoming dimmer?
2007-08-13 03:22:58 · 8 answers · asked by Azure Z 6 in Science & Mathematics ➔ Astronomy & Space
There doesn't appear to be any way for a photon to lose energy in space if it isn't absorbed or reflected. That's conservation of energy for you.
Yes, galaxies are definitely becoming dimmer the further away we measure them to be. Also, we can use Cephied variable stars to measure distances, as well as supernova. Oh, and look up the cosmic background radiation, which is another measure of the age of the universe due to temperature changes.
2007-08-13 03:29:01 · answer #1 · answered by eri 7 · 1⤊ 0⤋
The red shift is actually better thought of as due to the expansion of the universe: the wavelengths of the light get stretched. Since longer wavelengths correspond to lower energy, your view has some merit. For very close galaxies, the red shift can be thought of as due to a velocity red shift, but this is an approximation and really isn't a good way to think of things for more distant galaxies. But the overall conclusion that the universe is expanding is solid.
2007-08-13 06:12:15 · answer #2 · answered by mathematician 7 · 1⤊ 0⤋
The universe expands initially but is has a maximum size so it must eventually stop.
Aged photons could lose a bit of energy and shift towards the red.
The big question is the Hubble red shift.
It the universe is finite it can't be in a state of accelerated expansion,which the Hubble constant predicts.
Galaxies could appear to be moving away at an accelerated rate is they were collapsing to a central point,and accelerating toward the galactic center.
Some thing has to happen to galaxies as they move toward the end of their lives,and an accelerated expansion is not the answer.
2007-08-13 04:16:21 · answer #3 · answered by Billy Butthead 7 · 0⤊ 1⤋
Redshift is the only evidence so far that supports the expansion of the universe. Hubble, who first discovered the red-shift on distant galaxies to be increasing the farther the galaxies were, did not agree with the expansion hypothesis.
He felt, as do a growing number of people, that there could very well be a more plausible reason for the observed redshift.
2007-08-13 03:30:12 · answer #4 · answered by most important person you know 3 · 0⤊ 0⤋
That idea has been considered often. But nobody has been able to devise any experiment to show such an effect. If photons get red shifted because they are old or because they are traveling so far, how do you make an experiment to measure that? It is a really good idea, but how do you prove or disprove it? And if the universe is not expanding, then what keeps gravity from making it collapse?
2007-08-13 03:51:07 · answer #5 · answered by campbelp2002 7 · 1⤊ 0⤋
Well, you are thinking like a skeptic, like a good scientist. :) Yeh, the red shift is the only strong evidence, as far as I know. If you can poke a hole in the red shift evidence and suggest another reason for the red shift, the expanding universe theory facing serious issues.
2007-08-13 03:39:10 · answer #6 · answered by Anonymous · 1⤊ 0⤋
We are not sure, it is a theory. It will become a fact, when it is proven, which will never happen.
2007-08-13 06:03:09 · answer #7 · answered by John B 4 · 0⤊ 0⤋
Simple, We're not!
There isn't much thats "Sure" in scince.
2007-08-13 03:36:58 · answer #8 · answered by Anonymous · 1⤊ 0⤋