- Dark matter only interacts with ordinary matter via gravity.
- Dark matter has up to 4 times more mass than stars, dust, and gas that is visible in galaxies observed and measured.
- Dark matter was postulated by Swiss astrophysicist Fritz Zwicky in 1934 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters.
- This conclusion has been made because there is just not enough Baryronic matter (observable matter) visible that would account for the gravity needed to hold a galaxy together.
- Dark matter, which does not interact with electromagnetic radiation, is not only "dark" but also, by definition, utterly transparent.
- Dark matter makes up an estimated 23% of our universe based on current indirect observations.
- The vast majority of the dark matter in the universe is believed to be nonbaryonic, and thus not formed out of atoms.
- Dark matter is believed to be present within and around the Milky Way (and other galaxies), in the form of a halo.
- Baryronic matter makes up 4% of the universe. This means that 96% of the matter is currently not visible.
Dark matter - some facts
