Free-Floating Planets May be More Common Than Stars
jpl.nasa.gov
jpl.nasa.gov
From the article:
> A 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand is used to regularly scan the copious stars at the center of our galaxy for gravitational microlensing events. These occur when something, such as a star or planet, passes in front of another, more distant star. The passing body's gravity warps the light of the background star, causing it to magnify and brighten. Heftier passing bodies, like massive stars, will warp the light of the background star to a greater extent, resulting in brightening events that can last weeks. Small planet-size bodies will cause less of a distortion, and brighten a star for only a few days or less.
Basicly, there is not enough baryonic matter (stuff like protons and neutrons) in the universe to explain the observed effects of dark matter without invalidating a lot of other observations.