expanding universe
rallain | May 20, 2010I am going to try to answer another Ask a ScienceBlogger question. This one is from George P. Burdell. He asks:
"If the universe is expanding from the big bang, has anyone tried to reverse plot the galaxies to figure out the exact point where the big bang occurred?"
Actually, he asked two questions, but I am just answering the first. Second, let me note that I am not really a cosmologist - so I am just making up answer.
In short, the answer is that everywhere is the center of the universe. Think of it this way. Imagine that there are only two dimensions and these two dimension are the…
esiegel | April 11, 2008So, what's the deal with this one? startswithabang.com reader Scott Stuart asks the following question:
I was reading "The First Three Minutes" last night and came across an
interesting section about blackbody radiation and energy density. The
author states that as the universe expands, the number of photons
running around (in the CMB, for example) is unchanged, but their
wavelengths get stretched. The energy in a photon is, of course,
inversely proportional to its wavelength, so the energy content of a
photon decreases as its wavelength increases. That seems to mean that
the total energy…