Recent content by Deuterium2H

The hallowed principle of Conservation of Energy, which seems so inviolable in all other aspects of Physics, simply has no traction when it comes to modern Cosmology, and the measured fact of an expanding Universe. As I have stated in other threads, the simplest answer is to simply do away with...

Perhaps I misunderstood the question of the OP. The term Comoving Hubble radius only makes sense when measured at a particular instant of cosmological time, and it is dependent upon the coordinate (proper) distance at the time of measuement. And I agree, I have probably needlessly confused...

I didn't say that "all quantities measured in comoving coordinates are constant". I specifically said that comoving distances are constant. And any equation involving the Hubble paramater (which involves the scale factor) is time-dependent, because it is based upon proper distance at a given...

Ummm...no one has answered the question correctly so far. Comoving Coordinates (and Comoving distances) do NOT increase with the expansion of the Universe, and do not increase in time. That is the whole point of the Comoving coordinate system. Proper distances increase in time. The...

Jose, I encourage you to read the FAQ section of this forum (listed at the very top of this section). Many of your questions are answered in descriptive, non-rigourous and very accesible explanations. As has already been explained (e.g. Chalnoth), the known physics of our Universe does not...

Huh?? I don't even understand what you are trying to say. But as a possible correction, do not confuse a doppler red-shift (which IS a measure of relative velocity between two objects in space), and Cosmological Red-Shift, which is NOT a measure of relative velocity, but is a result of the...

The link Chalnoth provided is excellent, and it shows that the question of "energy" and "energy conservation" is both complicated and subtle in GR. Depending on the conventions or model one chooses may yield a different answer to the question of "energy conservation", especially in a global...

There is an equation (FLRW metric), and when it includes a cosmological constant term, which fits within observational parameters, yields a homogeous, isotropic Universe that is accelerating in it's expansion. As to your final question...the Universe isn't expanding into anything. Expansion...

Radrook, the link/source you cited appears to have a rather naive (incorrect) view of the mathematical concept of infinity. Infinity is not a "number" in the sense that it is not a member of the Natural Numbers, or the Reals, for that matter. However, both Analysis and Set theory deal with...

Chalnoth is correct. Energy is NOT conserved in an expanding Universe. Space can be both infinite and expanding.

Hello Tenelorn: Not sure exactly what you mean by "flat in amplitude". Did you mean uniform in distribution? In terms of the electromagnetic spectrum, the current 2.73K CMB radiation is the lowest temp / frequency we will be able to observe, as it is from the surface of last scattering at...

Wow...slow down there, Chronos, are you replying to me? Penzias and Wilson made the discovery, got the credit for it, and the Nobel. I agree with you that they initially didn't know what they had discovered, nor where they involved in Cosmological research, but the fact remains that they...

I might use the expression "later COBE and WMAP" put much greater precision into the measurements. The original Penzias and Wilson discovery was corroborated by hundreds, if not thousands of individual, separate ground based radio-telescope observations made after the initial discovery. COBE...

Fuzzles, a bit of a clarification... Inflation does not "validate" the Big Bang Theory, it is an adjunct to the theory which explains the issues you noted in your post. The "validation" of the Big Bang theory comes from multiple, independent observations. Typically, these are known as the...

Careful. You may be confusing the question of a Universe that is infinite in time, with a Universe that is infinite in space. We are 99.99999999% certain that our Universe is FINITE in time, i.e there was a beginning (Big Bang) approx. 13.7 billion years ago. In spatial extent, our Universe...