From Wikipedia:
"The most precise estimate of the universe's age is 13.7±0.2 billion years old..."
and,
"...space itself appears to have expanded. This expansion accounts for how Earth-bound scientists can observe the light from a galaxy 40 billion light years away, even if that light has traveled for only 13.7 billion years; the very space between them has expanded. This expansion is consistent with the observation that the light from distant galaxies has been redshifted; the photons emitted have been stretched to longer wavelengths and lower frequency during their journey."
I always thought light was red-shifted because the source was moving away from us. If space itself is expanding, causing light waves to expand, then wouldn't our observational tool also expand, negating any observable difference? How do they know that space is expanding, rather than the object moving away? This is the first time I've seen this, can anyone clarify?
2007-12-26
21:44:19
·
7 answers
·
asked by
Anonymous