Forget Dark Matter - beware of Dark Comets! Ever since the Mariner 4 Mars fly-by craft was battered by a severe meteor storm in 1967, it was a mystery where the meteors came from.
Now NASA thinks they have found the culprit - a "dark comet" (a broken up normal comet). Read more in this NASA link.
These things pose hazards to NASA's planned Mars exploration by astronauts.