Dark Fairy Tales

Tom Wilson: Dark Matter Recreations Part One.

There seems to be a growing cadre of theoretical astronomers who are focused on mathematical recreations centered on dark matter without observations or data to interpret.

In June 2008, Universe Today published a report from astronomers Siegel and Xu, predicting about 10^20 kilograms of dark matter in our Solar System that was accreted over the last 4.5 billion years. Quoting Siegel in the original paper:

“Overall, we find that dark matter in our Solar System is far more important than previously thought. Due to gravitational three-body interactions between dark matter particles, the Sun, and the planets, a significant amount of dark matter winds up gravitationally bound to our Solar System, resulting in density enhancements between two and five orders of magnitude, depending on the distance from the Sun.”

The paper begins by asserting dark matter as a reality, without any doubt as to its existence. Siegel begins the paper by citing evidence in three key areas that support the existence of dark matter: First, cosmic microwave background (CMB) evidence; second, galactic power spectrum analyses; and third, galaxy cluster collision evidence.

In part two of this article we will examine this underlying evidence in some detail. However, summarizing the Electric Universe position about the initial dark matter assertion, the underlying “evidence” for dark matter is not so much actual data, but the cosmological interpretations overlaid on actual data. The real observational data is red shifts, galactic distances, and cosmic background temperature gradients. All else is inference.

The approach Siegel and Xu took in computing the amount of dark matter in the solar system was based in the assumption that there is a certain dark matter density in the interstellar space surrounding the Solar System. They used a value of 0.009 solar masses per cubic parsec (one cubic parsec equals 9.78 cubic light-years), which amounts to about 7 x 10^-20 kilograms per cubic meter, or about 10 to 100 times the density assumed for “regular” interstellar matter.

They then used relatively straightforward calculations to compute the volume of space the Solar System encountered in its 4.5 billion year history. With that, they were able to calculate the gravitational capture of the dark matter given the relative velocities of the planets, the sun and the dark matter itself. Without getting into too much detail, they were able to estimate a dark matter density profile with respect to distance from the sun and the different planets.

According to Xu and Siegel, the Solar System has captured about 10^20 kilograms of dark matter over its 4.5 billion year history. Questions that should always be in the forefront when reading any scientific report include: how valid are the underlying assumptions for the work, and how useful is it for understanding the Universe?

Putting 10^20 kilograms of matter into context reveals it to be vanishingly small with respect to the Solar System as a whole. This amount of mass falls somewhere between the third and fourth largest asteroids (Vesta and Hygiea, respectively). The determination does nothing to explain Solar System dynamics or the anomalous behavior of space probes. How this vanishingly small amount of matter translates into “a significant amount of dark matter” is difficult to understand.

The key, according to Siegel, is that the dark matter density near the Earth (3.3 x 10^16 kilograms per cubic astronomical unit) is now shown to be four orders of magnitude greater than the background halo density. This statement is confusing. Translating the dark matter density close to the Earth into kilograms per cubic meter results in 10^-17 kilograms per cubic meter. Remember the interstellar dark matter density was 7 x 10^-20 kilograms per cubic meter, which looks like 2 to 3 orders of magnitude.

Regardless, Siegel claims this “discovery” will help dark matter investigators because they'll "know where to look." However, by definition, dark matter is unobservable so it is unclear how this benefit will be realized.

A different viewpoint demonstrates that these investigators have based a paper on assumptions about dark matter drawn from earlier papers that are themselves based on different types of assumptions about dark matter and the cosmological model. There is assumption layered on assumption to the point where there is no longer any need for actual data or observations.

It seems to be enough at this point to construct a Universe and Solar System that astronomers no longer actually observe in favor of mathematical recreations involving dark matter densities and so on. In the end, this work has led to a conclusion that a vanishingly small (one might say meaningless) amount of dark matter has accumulated in 4.5 billion years. I’m sorry, I do not find this enlightening.

I encourage astronomers like these authors in question to go out on a clear night with a simple optical telescope and take a good look. They will see a Universe that is brightly lit throughout the electromagnetic spectrum, with electrically active plasmas stretching between our Sun and the planets, as well as between the stars and galaxies.

During the day using a solar filter, they will see the electromagnetic activity of our own Sun tossing immensely hot filaments of plasma into space. With bigger telescopes, like Hubble, they can see intricately arrayed Birkeland filaments winding through planetary nebulae. The heart of our galaxy is brightly lit in a sparkling electromagnetic rainbow driven by powerful electrical currents carried on intergalactic transmission lines.

The Universe is not an abstract mathematical construct of dark matter halos, black hole singularities or geometrically perfect neutron stars. It is filled with electric currents flowing through chaotically beautiful Birkeland filaments. These chaotic filaments are notoriously difficult to squeeze into linear differential equations, but they’re there just the same. Just go look.