Is Dark Matter A Scientific Theory In Crisis?

There’s a very good scholar at USC Annenberg who works on the constraints that scientific institutions put on knowledge production, and who is absolutely convinced that dark matter is an explanatory non-starter. I’m not doing justice to his arguments, but he more or less thinks that it’s god-in-the-gaps reasoning and that some kind of modified theory of gravity will eventually be found to account for the anomalies. I tend to think that the evidence supports a theory of cold dark matter. Gravitational lensing and galaxy rotation and signatures in the cosmic microwave background and collision observations seem like diverse kinds of observations all converging on the same underlying dynamic.

But there’s definitely something strange going on. The role that dark matter plays theoretically is getting awfully specific, appearing in scientific explanations when anomalies exist but not in areas where the physics is well-understood.

Dark matter permeates the galaxy but can’t be detected in our own solar system because of instrument limitations? It exerts normal gravity when it’s holding galaxies together but not when galaxies are forming so a new force of nature has to be invoked? Its distribution matches models for the early universe but not for the modern universe so those models must have something wrong with them? It forms a galactic halo but doesn’t interact with the black holes in galactic cores and scientists simply can’t know why?

The research has all the feel – and, more importantly, exactly the rationalizations – that we’d expect of a scientific theory in crisis. Particularly stark is the proliferation of as-yet-undiscovered laws and mechanisms to explain away anomalies in as-yet-undiscovered laws and mechanisms, which were themselves invented to account for anomalies. Straightforward Peircean and Popperian theory predicts that non-crank scientists will eventually begin looking for alternative explanations that avoid creating a bunch of new things.

And wouldn’t you know it:

As one of many scientists who have become somewhat skeptical of dark matter, CERN physicist Dragan Slavkov Hajdukovic has proposed that the illusion of dark matter may be caused by the gravitational polarization of the quantum vacuum. “The key message of my paper is that dark matter may not exist and that phenomena attributed to dark matter may be explained by the gravitational polarization of the quantum vacuum,” Hajdukovic told PhysOrg.com… Hajdukovic’s paper on a dark matter alternative is also an attempt to understand cosmological phenomena without assuming the existence of unknown forms of matter and energy, or of unknown mechanisms for inflation and matter-antimatter asymmetry.

In the case of the fast rotational curves of galaxies, he explains that there are currently two schools of understanding the phenomenon. “The first school invokes the existence of dark matter, while the second school invokes modification of our law of gravity,” he said. “I suggest a third way, without introducing dark matter and without modification of the law of gravity.”

Hajdukovic’s account doesn’t explain away all the evidence for dark matter, but it does eliminate the original historical impetus for dark matter theories. It could be that dark matter theorists have been building epicycles on top of epicycles, except in this case insight into existing dynamics – rather than a radical new theory – will account for all the anomalies.

Photo:
* NASA / WMAP Science Team [Wiki Commons]

References:
* Modified Newtonian dynamics [Wiki]
* Bullet Cluster [Wiki]
* First observational evidence of dark matter [Darkmatterphysics]
* Dark Matter And Dark Energy Make Up 95 Percent Of Universe, Detailed Measurements Reveal [Science Daily]
* Colossal Cosmic Collision Reveals Mysterious Dark Matter [Space.com]
* Astronomers Create 3D Map of Dark Matter [Space.com]
* Galaxy study hints at cracks in dark matter theories [New Scientist]
* The core-cusp problem in cold dark matter halos and supernova feedback: Effects of Mass Loss [arXiv]
* Black Holes Not Affected by Dark Matter, Say Astrophysicists [arXiv blog]
* Dark matter may be an illusion caused by the quantum vacuum [Physorg.com]