[sjastro]

Hello Dana,

Originally Posted by Weltevreden SA

Hi again, Breammaster. By the phrase "atoms increasing mass as they age" I think you are referring to one of the explanations used in trying to understand how MOND works without doing the homework, namely “fat atoms”. MOND (Modified Newtonian Dynamics) was proposed in 1983 by Mordehai Milgrom as an explanation for the expanding universe long before the theory of Dark Matter originated and evolved into its present form. Milgrom's original point was that the properties of a De Sitter universe (basically Euclidian, or linear geometry) could be modified to reflect Einstein’s space-time explanation by multiplying the Gravitational Constant by the minute amount of a0 ≈ 1.2 x 10^−10 m/second, where a0 is the amount of acceleration that must be applied to Gravitational constant in order to account for things like the flat rotation curves in spiral galaxies and the expansion of the universe at the non-linear rate which has been observed. The number 1.2 x 10^−10 m s^−2 is a number so minuscule it would take a mosquito 2 years to get up to flight speed by using it.

The "fat atoms" probably relates to Arp-Narlikar's theory of variable mass.
This is one of the various offshoots of Hoyle's Steady State theory.
Like the Big Bang theory, steady state theories require the Universe to metrically expand, the difference being the density of a Big Bang Universe decreases with time where as density is constant in a steady state Universe. This requires mass to be "created" to compensate for expansion to keep the density constant.

Milgrom's theory (MOND) only deals with the dark matter problem, not dark energy which accounts for the accelerated metric expansion of the Universe.
The De Sitter universe model incidentally is a static model. There is no expansion of space. The model assumes that matter is evenly distributed through out space. The problem with this model is that the mathematics predicts the mass will exert a negative pressure and collapse onto itself.
To prevent this Einstein introduced his famous cosmological constant as a counterbalancing force to prevent collapse.
With the advent of expansion based cosmological models such as the Big Bang and Hoyle's Steady State theory, the cosmological constant was no longer needed until the Universe was found to undergo an accelerated expansion.
In this case Einstein's cosmological constant was reintroduced but took on a different context for an expanding Universe.

A lot of dither has been blathered over this eensy little number. Milgrom's paper is dense and densely argued. He was no crackpot—good friends with some of the leading lights of astronomy in the 1980s‚ Maarten Schmidt and Scott Tremaine being along them. The all-too ignored heroine of this era, Vera Rubin, quantified the flat rotation curves of galaxies first noticed by Fritz Zwicky in 1939. She leaned in favour of Milgrom's theory.

Fritz Zwicky's work did not cover the rotation curves of galaxies.
His coinage of the term dark matter related to the studies of the radial velocities of individual galaxies in clusters. He found the theoretical prediction for the radial velocities of galaxies in the Coma cluster did not match up with the measured values. This required more mass than was observed hence the term dark matter.

The Lerner paper you cited is a mangled edit of paper in the May 2014 issue of International Journal of Modern Physics D, May 2014, Vol. 23, No. 06 by Eric Lerner, Renato Falomo, and Riccardo Scarpa in May, 2014, “UV surface brightness of galaxies from the local universe to z ~ 5” That paper is unquestionably the worst astronomy paper I have ever come across, and believe me, there are more than a few real stinkers out there. I was so pissed off by the bad astronomy the Lerner paper represents that I got seven pages into a point-by-point refutation before I said, "Whoa" and threw the whole thing into the rubbish tip. Along with the Lerner paper, where it belongs.

Agreed.
Lerner's paper is rubbish.
One of the flaws in Lerner's paper (at least in the edition I have read) is his failure to address the time dilation of type IA supernova light curves.
A tired light theory cannot explain this.
In an expanding Universe on the other hand the Tolman surface brightness test and time dilation of the light curves are self consistent.

Beware glib phrases lie "tired light" and "fat atoms". They are products of uninformed minds which are also too lazy to look things up.

If the term fat atom is attributed to Narlikar, I wouldn't exactly refer him as having an uninformed mind. He is a foremost expert on General Relativity as has written several books on the subject.

His doctoral advisor was Fred Hoyle which probably explains his preference for a Steady State model.

Regards

Steven