Move over dark matter, here comes the photon mass

Posted: March 6, 2019 by oldbrew in Astrophysics, Celestial Mechanics, research

Spiral galaxy NGC 5457 aka the Pinwheel Galaxy [image credit: European Space Agency & NASA]

OK, that’s not the original title of the article below – but it sounded a bit more interesting from a layman’s perspective 🙂

The rotation of stars in galaxies such as the Milky Way is puzzling, says

The orbital speeds of stars should decrease with their distance from the center of the galaxy, but in fact, stars in the middle and outer regions of galaxies have the same rotational speed.

This may be due to the gravitational effect of matter that we can’t see. But although researchers have been seeking it for decades, the existence of dark matter has yet to be definitively proven and we still don’t know what it might be made of.

With this in mind, the physicists Dmitri Ryutov, Dmitry Budker and Victor Flambaum have suggested that the rotational dynamics of galaxies might be explained by other factors. They hypothesize that the mass of photons, which are particles of light, might be responsible.

Professor Dmitri Ryutov, who recently retired from the Lawrence Livermore National Laboratory in California, U.S., is an expert in plasma physics. He was awarded the American Physical Society’s (APS) 2017 Maxwell Prize for Plasma Physics for his achievements in the field.

Physicists generally credit Ryutov with establishing the upper limit for the mass of the photon. As this mass is extremely small, even if it is non-zero, it is usually ignored when analyzing atomic and nuclear processes. But even a vanishingly tiny mass could, according to the collaborative proposal, have an effect on large-scale astrophysical phenomena.

While visiting Johannes Gutenberg University Mainz (JGU), Ryutov, his host Professor Dmitry Budker of the Helmholtz Institute Mainz (HIM), and Professor Victor Flambaum, fellow of the Gutenberg Research College of Mainz University, decided to take a closer look at the idea.

They were interested in how the infinitesimally small mass of the photon could have an effect on massive galaxies. The mechanism at the core of the physicists’ assumption is a consequence of what is known as Maxwell-Proca equations. These would allow additional centripetal forces to be generated as a result of the electromagnetic stresses in a galaxy.

Are the effects as strong as those exerted by dark matter?

“The hypothetical effect we are investigating is not the result of increased gravity,” explained Dmitry Budker. This effect may occur concurrently with the assumed influence of dark matter. It may even—under certain circumstances—completely eliminate the need to evoke dark matter as a factor when it comes to explaining rotation curves.

Rotation curves express the relationship between the orbital speeds of stars in a galaxy and their radial distance from the galaxy’s center.

“By assuming a certain photon mass, much smaller than the current upper limit, we can show that this mass would be sufficient to generate additional forces in a galaxy and that these forces would be roughly large enough to explain the rotation curves,” said Budker. “This conclusion is extremely exciting.”

Full report here.


See also: Transfer of atomic mass with a photon solves the momentum paradox of light (2017)

  1. pochas94 says:

    My unlettered guess would be that the entire galactic disk is magnetically coupled. No need for dark matter, which would have to have a funky distribution.

  2. HM says:

    I’ve read peripheral suggestions that photons are dialectric, which I think means: is a kind of insulation by carrying electric charge statically. I couldn’t figure that out, and now I can’t figure out if this Proca stuff is the same thing.

    “Maxwell-Proca electrodynamics corresponding to finite photon mass causes substantial
    change of the Maxwell stress tensor and, under certain circumstances, may cause
    electromagnetic stresses to act effectively as “negative pressure”

    “The effects discussed in this paper … are driven not by the gravity force, but by the peculiar electrodynamic force present in the Proca model and may co-exist with gravity-driven effects … the stresses act predominantly on the interstellar gas and cause an additional force pulling the gas towards the center”

    With the age of the stars guiding this “negative pressure” that “co-exists” with gravity?

  3. stpaulchuck says:

    gee, next thing you’re going to tell me dark energy doesn’t exist, but is an artifact of ‘ordinary’ matter and forces. And here I was just going to put up ads in Popular Mechanics for my “Free Power From Dark Energy” machines. Darn.

  4. JB says:

    pochas94 I’ve been of a similar view on this. The force driving the planets in their orbits and rotation is the same force moving the sun and its rotation in the galactic arm, the rotation of the arms, etc..

    I also believe the explanation has been sitting right under their noses since Spolter published her analysis in 1993. Along with dark matter being dismissed by Rubin & Bosma (, the Peratt-Scott simulation ought to provide some pertinent insight into how the rotation curves have bearing.

    But everybody is too busy publishing to pay attention to what has already been learned.

  5. stpaulchuck says:

    I’d forgotten about those papers (well, it has been over two years). Then diving deeper into MOND and a couple other theories I come down to it being bad or incomplete data. For instance, it is only now that we have such marvelous IR detectors, x-ray detectors (and others) up in space that give us a much better ‘look’ at the universe beyond the limitations of visible light. In particular the new mass data derived from them is making waves as new correlations seem to pop up every day.

    I expect as newer observation tools pop up we’ll get some jaw dropping revelations. Every day brings us a little closer to _begin_ to understand the universe. *grin*

  6. pochas94 says:

    I think the configuration of the spiral arms suggests that they are under magnetic tension, with the outer stars being pulled along with the inner stars, so that the galaxy is effectively a rigid body. Also, note there are an even number of arms, also suggestive of magnetic poles, and that the galaxy pictured is quadrapolar.

  7. oldbrew says:

    Astronomers discover galaxies spin like clockwork
    Posted: March 14, 2018

    Professor Meurer said that by using simple maths, you can show all galaxies of the same size have the same average interior density.
    – – –
    “By assuming a certain photon mass, much smaller than the current upper limit, we can show that this mass would be sufficient to generate additional forces in a galaxy and that these forces would be roughly large enough to explain the rotation curves,” said Budker. “This conclusion is extremely exciting.”

    And leaving dark matter theory in tatters?

    What if It’s Not Dark Matter Making The Universe’s Extra ‘Gravity’, But Light?
    7 MAR 2019

    We’ve been looking for decades for dark matter, yet the mysterious stuff remains undetectable to our instruments. Now, astrophysicists have explored an intriguing possibility: what if it’s not dark matter that’s affecting galactic rotation after all. What if it’s the mass of light instead?

  8. Amit Rana says:
    Photon and heat relationship

  9. oldbrew says:

    Sorry Amit but the experts say photons do have mass – see blog post.

    Photons have energy, and energy is equivalent to mass: E = mc²

  10. gymnosperm says:

    Another quandary is why dark energy only applies to the space between galaxies and not within them. Galaxies become the indivisible “atoms” in the supposed vacuum energy field.

  11. oldbrew says:

    More evidence of sound waves carrying mass
    March 6, 2019 by Bob Yirka,

    A trio of researchers at Columbia University has found more evidence showing that sound waves carry mass. In their paper published in the journal Physical Review Letters, Angelo Esposito, Rafael Krichevsky and Alberto Nicolis describe using effective field theory techniques to confirm the results found by a team last year attempting to measure mass carried by sound waves.

    Read more at:

  12. stpaulchuck says:

    oldbrew says:
    March 7, 2019 at 7:49 pm

    Seriously Rog?? sound ‘waves’ are nothing but displaced mass that already exists. Nothing is added (except energy of course).

    “In space, no one can hear you scream.” – Alien –

  13. stpaulchuck says:

    you know, now that I think about what I posted, I stand corrected by Einstein. Mass increases as velocity increases, rising to infinity at the speed of light (at least according to him and experiment). So guess sound waves, which are moving mass, can gain mass, but such a small amount as to be basically undetectable with ordinary devices.

  14. oldbrew says:

    Miles Mathis weighs in…

    Today, a reader alerted me that ScienceAlert just posted an article with the title What if It’s Not Dark Matter Making The Universe’s Extra ‘Gravity’, But Light? You mean like I have been telling them for a decade? Do they mention me or link to my papers on the subject? Of course not. They simply signal the plan to steal it, as they have been stealing so many other of my ideas.
    . . .
    So if they expect to survive my lawsuit on this—or anything else—I suppose they will have to find some way to wipe not only my hard drive and the hard drives of all my readers, but also the Wayback Machine. And if anyone thinks my work is not copyrighted, they are sadly mistaken.

    Click to access charlight.pdf

    ‘telling them for a decade’ —

  15. pochas94 says:

    Since the higher energy photons at the center of the galaxy would carry higher mass, I can’t see how this theory helps the velocity distribution problem. What am I missing?

  16. Gerry Pease says:

    I like this hypothesis because it is a very simple and understandable possible explanation of galactic dark matter: LIGHT matter. This could explain “dark energy” as well I think. My opinion should have some weight in the scientific community because I was a coauthor of Vera Rubin’s 1962 paper attempting to measure our galaxy’s rotation curve.

    Click to access nph-iarticle_query

    [mod] link

  17. Gerry Pease says:

    Thanks for the modified link, oldbrew. This one hopefully works:

    Click to access nph-iarticle_query

  18. oldbrew says:

    Bad luck Gerry – WordPress gremlins! Always happens with those dots…
    – – –
    At least the photon mass idea is based on something known to exist.