The gist of things is that, although there has been much indirect evidence for dark matter, there have also been many skeptics, both among astrophysicists and in the general public.
Uncomfortable with the idea of dark matter as a postulated solution to a number of astrophysical puzzles, the skeptics have devised a number of alternative explanations for the various anomalies -- often by attempting to modify long-accepted principles of Newtonian gravity and general relativity.
But heedless of the skeptics, evidence for dark matter just keeps piling up. Here is the latest, just released today, and it is a lot less indirect than previous evidence:
NASA Finds Direct Proof of Dark Matter
Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter.
"This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it is stronger on intergalactic scales than predicted by Newton and Einstein, removing the need for dark matter. However, such theories cannot explain the observed effects of this collision.
For more commentary, see this at particle physicist Clifford Johnson's Asymptotia.
Tags: dark matter, astrophysics
Links to this post: