Split Thread Michael Mozina's thread on Dark Matter, Inflation and Cosmology

[W.D.Clinger]

I hate to give Michael Mozina any hints on his math homework, but this was too funny to let pass without comment.

In equation (33), how can v*V be v^2 yet v-V be not zero?

I think Giggywig is referring to equation (35), not equation (33).

Equation (35) contains mistakes I hadn't noticed before Giggywig's post. The author probably intended for the difference between v*V and v^2 to be absorbed into the error term, but he screwed up both the magnitude and the units of the error term. The magnitude of the error term is way too small, but more obviously: The error term should be in units of velocity, but it's in units of area instead.

 

[W.D.Clinger]

With regard to:
http://arxiv.org/abs/astro-ph/0601171

On the other hand, it's possible that equations (36), (37), (38), (39), (5), and (3) can be established without relying on equation (33). I'll offer you a deal: If you can show me a correct derivation of equations (36), (37), (38), and (39) without relying on equation (33), then I'll read the paper.

That offer (to Michael Mozina) still stands, but I'll give him a freebie by reporting on the first two sections of the paper and quoting an amusing bit from section 4.

Equations (1) through (10) look okay. Equations (2) through (10) are in section 2, which derives the special relativistic kinematics of the Doppler effect. This derivation is essentially the same as the one I saw in (an honors section of) physics 101.

Appendix A appears to be the author's attempt to derive equation (5) using more sophisticated mathematics, which the author screwed up. The only apparent purpose of this more difficult derivation is to prove a claim quoted from John Peacock's book on cosmology. When skimming the rest of the paper, I didn't see any technical content that depends upon the Peacock quotation or Appendix A.

I did find several statements such as the following, however, which lead me to wonder why Michael Mozina believes this paper supports his beliefs, and why he is so eager for us to read the paper.

In almost all Friedman models, objects with sufficiently large redshifts recede from the central observer with superluminal velocities (greater than c)....Does it imply violation of special relativity in cosmology? Of course not.

The paper also accepts current estimates for dark energy.

 

[W.D.Clinger]

Just got around to looking at this...

There are more recent papers by the way:

http://arxiv.org/abs/0911.3536

Once again, you have directed us to a paper that negates your argument.

From its abstract:

In particular, in a universe with Omega_m = 0.24 and Omega_Lambda = 0.76,

For your information, Michael, those parameters approximate currently accepted values for (mostly dark) matter and for dark energy.

Last but not least, we show that the so-called proper recession velocities of galaxies, commonly used in cosmology, are in fact radial components of the galaxies' four-velocity vectors. As such, they can indeed attain superluminal values, but should not be regarded as real velocities.

For your information, Michael, that highlighted bit is exactly what various people here have been telling you for some time.

So why should we read yet another random paper that (quite obviously) does not support your beliefs?