My apologies. Interesting topic and I just came across it this morning. Of course, to really speak to a topic like this you would want to look at the actual research and review the data that they collected. I don’t have time for that right now. But while making breakfast I gave it some cursory thought and, in my mind, there are multiple potentially plausible explanations in addition to some unseen dark matter or dark forces to which the celestial bodies respond.
First let’s get to the gravity of the situation or at least how it was best described to me by a friend who is a physics professor. He explains the gravitational force as merely the shortest distance between masses or energy densities in the curvature that they create in the space-time continuum. Within this explanation of gravity is a couple of potentially plausible explanations for the phenomena of celestial bodies moving together as if there were some unseen mass or forces guiding their motion despite the distances between them seeming to be too great with an inverse square drop off in the effect from the force of gravity.
- Perhaps what influences these galaxies is not dark matter but rather a large system of masses too small for each to individually be detected by current methods but collectively, extremely massive and spread over enough distance that the system of masses has a large gravitational pull that is also extended over greater distances as a result of the masses having a greater spread throughout the space. Think of this explanation as if the galaxies that the researchers were following were shells that catch our eye on a beach, spread pretty far apart, but connected through the many times more prevalent and collectively greater mass, but individually much smaller, granules of sand underlying the shells.
- Another potentially plausible explanation is that an energy density or a system of energy densities distributed throughout the space are influencing the galaxies. E=mc^2 so mass is really a form of potential energy which can be released in ridiculously small amounts during chemical reactions, in still relatively small amounts during nuclear reactions, but in totality during particle-antiparticle annihilation. So perhaps there is a great enough rate of particle/anti-particle annihilations spread throughout the space between these galaxies to collectively bind their movements.
- Another potentially plausible explanation is that there is a memory to or lag in the space-time continuum response to mass and energy densities. Galaxies that once were closer together created curvature of space-time and some residual curvature remains over the now greater separation distance between the galaxies.
- Perhaps the curvature of space-time due to mass and energy densities has a damped wave-like behavior to it that is like ripples on a pond when you toss a stone. The amplitude of the space-time continuum curvature wave is greatest near the mass or energy density and falls at the inverse square of the separation distance rate but the maximum disturbance of the space-time continuum at the mass or energy density creates a minimum disturbance at half of the wavelength and then repeats with successively smaller maxima of the damped wave one wavelength apart thereby allowing the galaxies to interact with one another over a greater distance.
- The methods and results of the researchers require scrutiny. They can present findings but perhaps their methods completely overlook critical (such as collections of smaller but individually undetectable mass or energy density systems spread over vast distances) or are limited or even subject to systematic error (which can be many times larger than the actual measurements in this particular field).
- Lastly, I will say that there is so much that we truly don’t know about our world. This is why it always amazes me how certain humans can often be in thinking that we know all of or can control our world. The history of follies associated with our certainty of things particularly in science would be comical if it weren't also often tragic. This is why I tend to be pretty skeptical with regard to any certainty pushed by laymen (politicians, news reporters, etc.). Half of them don't even understand the basics of the science that they claim is so certain. Real scientists always continue to question. That is nearly the definition of science. It is not a poll. It is not a current belief. It is continuing to question using rigorous methods to test our hypotheses and that extends to science which might be considered to be settled. We often learn through greater scrutiny that what we believed was true is either not or only true for specific conditions.
bigthink.com
