


We don't know what's responsible for it, but we call that mystery source dark matter, and there are several theoretical candidates that scientists are investigating.īroadly, these candidates can be divided into two categories: single particles, and composites, including macroscopic blobs of dark matter, or Macros, that could have planet-scale masses. Once you've accounted for every galaxy, every star, and every cloud of dust drifting silent and dark between the stars, there's still way more gravity than there should be.
