Dark Matter Revisited, Real or Memorex?
Fritz Zwicky, unsung genius.
As a break from the ongoing blood and puppet shows in the Middle East, dark matter! What the heck is dark matter? Nobody knows. See, this was an easy blog. Well, it’s not quite that simple. Dark matter is a scientific mystery, and both an example and a warning about inferring the existence of the unknown from the known.
First, dark matter. (There is also dark energy, but I don’t even want to go there.) Scientists infer that something called dark matter exists, even though they can’t detect it directly. Scientists theorize that dark matter exists because of puzzling discrepancies in what they observe of the universe. They are literally seeing the unseen by the effect it has on the visible universe. More on this below.
A good example of how the unseen is inferred from the seen is the historical discovery of the outer planets. After Newton’s discoveries about gravity and physics, astronomers were able to precisely predict the path of the planets through the sky. Problems eventually arose, there were irregularities in the orbits of the outer planets, Jupiter and Saturn. Uranus, Neptune, and Pluto cannot be seen with the naked eye and were not discovered until the scientific era. (Not quite true, under optimal conditions Uranus is visible to a person with good vision, but it’s so faint and rarely visible that it’s no wonder the ancients didn’t notice it.) By studying the irregularities in the orbits of Saturn and Jupiter, scientists predicted there were other planets. Using their knowledge of physics, they predicted and then discovered Uranus, Neptune, and Pluto.
In the very same fashion, looking at the universe at large, scientists see irregularities that defy the laws of physics. The galaxies for example don’t have enough visible mass to stop from flying apart as they spin, among other irregularities. Scientists conclude that some sort of invisible matter must exist to account for these discrepancies. And thus dark matter was born. Long story short, maybe dark matter is some sort of ordinary matter that is hidden somehow, burned out suns, non reflective gas, who knows. The other possibility is that dark matter is some sort of invisible subatomic particle or particles that are invisible but still exert gravitational attraction.
All current theory and observation is that dark matter is the later, it’s sort of the invisible lattice or framework that the rest of the universe is built upon. Science has even mapped out the distribution of dark matter, and there have been exciting discoveries recently. Um, exciting if a person gets excited about physical cosmology. And that in a nutshell, is that. Dark matter is a blank spot in our understanding of the universe, Terra Incognito if you will, but it will be discovered eventually.
Except of course, maybe dark matter doesn’t exist at all. Going back to our planets example, there were irregularities in the orbit of Mercury that also couldn’t be explained. Astronomers spent a lot of time and effort looking for the hypothetical planet they named Vulcan, that just had to be orbiting somewhere near the Sun and Mercury. There was and is no planet Vulcan, it turned out science didn’t know as much about physics as they thought they did. A fellow named Einstein came along and upset the applecart with his theory of relativity. When relativity was plugged into the equation, the irregularities in Mercury’s orbit were very neatly explained. So neatly in fact that it is considered one of the proofs that Einstein’s crazy sounding theory is actually correct.
So I have no opinion on dark matter, to even talk about physical cosmology one has to know math that would make an amputation seem pleasant in comparison. I like the idea of an invisible matrix holding the universe together, that certainly doesn’t contract any spiritual beliefs I am aware of. Maybe even the opposite. There’s also hints that there may be something beyond Einstein, the so called Pioneer Anomaly has made scientists scratch their heads for a few decades now. For some as yet unknown reason these two early space probes are moving slower than by all rights they should be. Some invisible force appears to be holding them back slightly. Maybe some future or current genius will come up with a theory that explains the observed problems in cosmology without invoking invisible mass. I’m glad scientists are working on the problem, and I will report new developments in this field as I become aware of them.
Speaking of awareness, it has been brought to my attention that one of the people who originated the concept of dark matter did not get the credit he deserves. Fritz Zwicky, a brilliant astrophysicist, has been neglected in the history books. He was a brilliant scientist who contributed a great deal to our understanding of the cosmos, and by all accounts a fine human being. Rest in peace Fritz, you and your contributions shall not be forgotten.
(The above image is claimed as Fair Use under US copyright law. It is not being used for profit, it is central to illustrating the post, and it is an historically important image.)