What is dark matter?
“Dark Matter” generally refers to “exotic” non-baryonic matter that interacts only weakly with ordinary matter. While no such matter has ever been directly observed in the laboratory, its existence has long been suspected. Radio and optical observations of gas and stars in distant galaxies enable astronomers to determine the distribution of mass in these systems. The mass that astronomers infer for galaxies including our own is roughly ten times larger than the mass that can be associated with stars, gas and dust in a Galaxy. This mass discrepancy has been confirmed by observations of gravitational lensing, the bending of light predicted by Einstein’s theory of general relativity.
Dark Matter is weird stuff — “non-baryonic matter,” as Scientific American editor George Musser puts it in this minute and a half take on the nature of the mystery substance that makes up the majority of the mass in our universe. This is episode 1 of our new video podcast, which you can subscribe to via iTunes, or via RSS, or check out at our new site, 60 Second Science.
