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Our future, our universe, and other weighty topics

Thursday, February 12, 2015

The Euphemism Known as Dark Matter

A new scientific study claims to have found evidence for dark matter in the inner parts of our galaxy. In a nutshell the authors reasoning seems to be something like this:
  1. Effects that we see in our galaxy must be either the result of ordinary matter or some unknown type of matter (dark matter).
  2. There is some stuff going on in our galaxy that is hard to explain by assuming it is just the effects of ordinary matter.
  3. Therefore, dark matter must exist in our galaxy.
I don't find this reasoning to be convincing. One reason is that there are several other possibilities other than dark matter to explain such observations. One possibility is a dark force.

We understand four fundamental forces that act on matter, but there is no reason to assume that we have discovered all of the forces that may exist between material forces. There may be undiscovered physical forces acting between known types of material particles. We may call such unknown, mysterious forces dark forces. This idea has nothing to do with “the dark side of the Force” discussed in the Star Wars movies.

Scientists have considered the possibility of such dark forces, but don't seem to like the idea. When I use this link to search for physics papers with “dark force” in the title, I get only 62 papers. But when I use the same site to search for papers with “dark matter” in the title, I am told that I have reached the search limit of 1000 papers.

Clearly scientists are much, more comfortable with the idea of dark matter than the idea of dark forces. Why might that be? I think it is related to the fact that scientists like to pretend that they understand all the basic forces at work in the universe (even though such confidence is unjustified). If scientists start talking about a dark force, it will be an admission that they don't really understand the mysterious influences at play in our baffling universe.

There is one reason why we should not assume that some unexplained behavior of matter is caused by the influence of dark matter. Besides the possibility of dark forces, there is also the possibility of various undiscovered types of dark energy. When scientists think of dark energy, they think of something that is the same throughout the universe. But that's just one type of dark energy. For all we know, there could be 10 different types of dark energy at play in the universe. Some of those types could appear in greater concentrations in particular parts of the universe.

So almost any observation that can be explained as being the result of dark matter can also be the result of an undiscovered dark force or some undiscovered type of dark energy. Is there any real substance behind this idea of dark matter? Apparently not. The very successful Standard Model of Physics says not one single thing about dark matter.

It seems that dark matter is basically a kind of euphemism, a fancy way of saying, “Some sort of something,” a verbal way of dressing up a vaporous question mark. Every time that a scientist refers to dark matter, he could just as accurately use the term “Unknown Influence, Possibly Material (UIPM).” That would be a more candid phrase. But the term “dark matter” sounds better. It makes it sound as if scientists have latched on to something substantial, even when they have nothing more substantial in their hands than a person trying to catch moonbeams.

I will illustrate this point by showing some hypothetical newspaper headlines that show how well the term “dark matter” works at helping cosmologists feel better. The first headline is a candid headline that could have been produced after the recent survey trying to account for our galaxy based on known material particles.

The second headline discusses the same scientific result. But now it all sounds different. The slick term “dark matter” is used to make it appear that something concrete has been discovered. Thus is a ghostly vapor of a bafflement dressed up in a dark dress, to make it appear substantial.