Dark New Ideas About Cosmological 'Dark Matter.'

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Many years on, and many, many, many dollars spent, scientists still don't know what the mysterious 'dark matter' is. They claim that it is there and claim to have indirectly detected it, but its assumed properties and behaviors continue to get increasingly 'weird.' Are astronomers on the wrong path?

To briefly recap the reasoning behind the addition of 'dark matter' to the astronomer's toolkit (despite it never having been directly detected):

The simple fact that this all boils down to a failed prediction and a mathematical 'fudge factor' introduced to balance equations that did not correspond to actual observations.

If we consider only the gravitational force to play any formative or regulatory role in the universe, there is simply insufficient detectable matter to account for celestial motions. Gravity alone would need about 5 times more matter than what we can observe to be present in order to 'fix' the predicted rotation curves of galaxies so that they match observations. 'Dark matter' paints that 'missing' matter into the picture.

Some new suggestions have recently been made with respect to 'dark matter.' Both are a bit perplexing and thus far unsupported by direct observations (much the same way that 'dark matter' began its theoretical life).

First, theorists Leonid Chuzhoy and Rocky Kolb of the University of Chicago have suggested that dark matter may have an electric charge.

Now, Lotty Ackerman and colleagues at Caltech in Pasadena have tentatively proposed that dark matter emits its own variety of 'dark light' or 'dark radiation,' with the assumption that 'dark matter' interacts in a fashion similar to or the same as the electromagnetic force.

Both propositions seem to be at odds with the typical definition of dark matter:

In other words, dark matter is supposed to emplace additional matter / mass into the gravitational model (fudging the numbers so there's more mass than what is actually observed), but not interact in other ways, such as electromagnetically.

One should probably avoid conflating the two proposals, however they bring up an interesting point to make about regular electromagnetism and the electromagnetic spectrum.

In standard physics, light, electricity and magnetism are all intertwined. The basic particles are electrically charged (except the neutron which is considered electrically neutral; anecdotally, however, neutron-neutron repulsion may indicate otherwise). When like charges flow in the same direction and are not accompanied by an equal number of opposite charges, it is considered an electric current. A magnetic field is formed around an electric current. Atoms are composed of charged particles in certain mostly-stable configurations. Under some circumstances, atoms can absorb or emit electromagnetic radiation (light).

The recent articles about 'dark matter' make it seem as though scientists are trying to get 'dark matter' to do the things that charged particles do, but without abandoning their current conceptual scaffolding.

If 'dark matter' is now being tentatively theorized to consist of charged particles (massive or otherwise) and to emit 'dark light,' one is tempted to wonder aloud whether other aspects of the electromagnetic spectrum and electromagnetic fields will have to manifest themselves in this 'dark' new universe?

Would these 'dark' charged particles have the typical positive and negative electrical signs of protons and electrons? If so, could the 'dark' charged particles take part in 'dark' electric currents? If so, what would that look like? Would 'dark' electric currents function in the same way as standard electromagnetism and/or adhere to the various formulae derived by Maxwell, Ampère, Faraday, Lorentz and Gauss (among others)? Would 'dark' electric currents produce magnetic fields? If so, would they appear as normal magnetic fields or 'dark' [invisible] magnetic fields? Would either interact with normal 'visible' / 'detectable' charged particles? Could 'dark' charged particles form 'dark' atoms, which might emit 'dark radiation'? Could 'dark' charged particles themselves produce 'dark' radiation when spiraling through magnetic fields ('dark' or otherwise), as 'visible' charged particles do when emitting synchrotron radiation? Might there be an entire 'dark' electromagnetic spectrum out there that we've yet to discover? (In fact, just such speculations have already been tentatively made by Caltech team member Sean Carroll!)

Perhaps, however, scientists have simply made some incorrect assumptions about the workings of the universe. As Rocky Kolb said, "we have to keep our minds open," and as Avi Loeb echoed "it's always healthy and important to explore unconventional possibilities."

'Dark matter' may be unnecessary in its entirety, if accurate results can be obtained through other means without resort to inventing new entities or 'new physics.' After all, falsification is a cornerstone of science. Astronomers predicted galaxy rotation curves on the basis of the amount of gravitating matter visible at the wavelengths we are capable of observing. The predictions failed spectacularly. 5 times more matter would have to be present in order to correct the predicted curve to fit observations.

The choice was to either increase the mass estimate by a whopping 400% [more than that which it's possible to observe] and simply assume [postulate] that something is there to justify that increase (that's where 'dark matter' comes in) or falsify the model that predicted the spectacularly wrong rotation curve and try to find a better fit elsewhere.

Astronomers opted for the former. They postulated a new entity and 'new physics' to go with it. But what lies down the road not taken?

One possibility that has been largely ignored is Plasma Cosmology.

Rather than assuming that gravity is the only player on the largest scales of the universe and rather than assuming that space is electrically neutral up to the largest scales of the universe, it assumes that there are dynamic electric and plasma processes occurring that may give rise to stars, galaxies and the gross structure of the universe.

What's more, as early as 1986 it has shown that particle-in-cell computer simulations using electric interactions rather than gravitational interactions (the naked electric force is 39 orders of magnitude stronger than the gravitational force) as the underlying assumptions appear to give better accord with galaxy rotation curves without introducing any additional hypothetical entities. (See: Evolution of the Plasma Universe: I. Double Radio Galaxies, Quasars, and Extragalactic Jets, A. L. Peratt, IEEE Trans. Plasma Sci. Vol. PS-14, N.6, pp.639-660, December 1986 and Evolution of the Plasma Universe: II. The Formation of Systems of Galaxies, A. L. Peratt, IEEE Trans. Plasma Sci. Vol. PS-14, N.6, pp.763-778, December 1986.)

Furthermore, the model allows for the sorting and clumping of more-or-less electrically neutral matter (such as that in the solar system which has been so well described by simple gravitational equations for so long), by way of Marklund convection, into regions where gravitational interactions dominate.

While it's currently not well or widely received, Plasma Cosmology may offer a way out of this increasingly 'dark' age of astronomy and astrophysics. Should we really allow physics to be dominated by what we can't see and to largely exclude from discussion that which we can (ubiquitous magnetic fields through out the universe that strongly imply electric currents must be flowing)?