Tuesday, July 28, 2009

1) Dark Matter

Dark Matter is a special form of matter that is hypothesized to explain certain anomalies in the formation and behavior of galaxies, which has been the subject of a great deal of attention and debate in the areas of physics and astronomy over recent years. Over the next few weeks I plan to publish a series of posts on the subject, and along the way, propose a possible alternative to current, and prevailing thinking on the matter.

The concept of Dark Matter was first put forward as a possible explanation for some of the odd characteristics of galaxies that cannot be fully explained based on current notions of gravitation. In a nutshell, it is presumed that gravity is the only binding agent that holds galaxies together. Based on this simple and reasonable assumption, it seems obvious that there must then be enough matter in any given galaxy to account for the fact that it is able to hold its shape.

The problem is that given the rotation of most galaxies (maybe all), there does not seem to be enough matter within them to account for the fact that they do not simply fly apart. If we imagine rotating galaxies as enormous carousels, there is simply not enough detectable matter to create the amount of gravity required to hold them together. This simple fact is intriguing enough, but even more remarkable when we realize that this discrepancy is anything but small. Estimates vary, but overall it seems that a typical galaxy contains only 30% or less of the matter required to hold its shape.

Enter Dark Matter. Dark Matter is a type of matter that has been hypothesized to explain this discrepancy. Dark Matter particles are thought to be virtually undetectable in all respects except for the obvious effects of their gravitational influence on normal matter, yet constitute 70% or more of a typical galaxy's total mass.

Astronomers and physicists have been trying to detect, and otherwise prove or disprove the existence of Dark Matter particles for years. Certainly, no one can say for sure that they don’t exist, especially since their existence would conveniently explain what seems, in all other ways, to be inexplicable. But, drawing for a moment upon the sensibilities of Occam’s Razor, this explanation seems a little too tidy somehow.

Indeed, this is a common pitfall in all research-related disciplines; that the solution to a given problem is often envisioned as a mere reflection of that problem. In this case, the need for something in the Universe to account for the apparent lack of visible matter gives rise to speculation about exotic particles that precisely fit the needed description: invisible matter that produces gravitational effects.

There may be a more reasonable and feasible explanation; one that does not require the existence of hopelessly exotic Dark Matter particles. I have written a full article describing this alternative (actually, several years ago), but would like to publish a series of introductory blogs (which I am calling the Dark Matter Series) to help explain a few simple concepts before publishing a link to it here.

And by the way, thanks for reading!