Machos (MAssive Compact Halo Objects) include all bodies in space made up of baryonic matter (normal atoms) which are massive and relatively dense. The Halo in the name comes from the fact that most dark matter should exist in rings around galaxies. The Machos which could account for Dark Matter include stars which don't have enough mass to burn, small stars which have used up their fuel and collapsed to brown dwarfs, or large stars which have used up their fuel and collapsed to form black holes. There may be other anomalies taking the form of Machos which could account for dark matter, but we haven't been able to predict them with current theory.

It is much harder to prove the existence of Machos than WIMPs, because they are all far away and can't be seen. Wimps can't be seen either, but they are present nearly everywhere in the universe. Astronomers have proved the existence of black holes to a small degree of certainty, and even less for brown dwarfs. However, we are confident they exist and can prove it using Einstein's theory of relativity, but we also know that they could not make up for all the missing mass in the universe. By looking at the number of stars still burning and the age of the universe, physicists know approximately how many black holes and brown dwarfs there are, and their combined mass doesn't come close to the amount of dark matter which must exist.

• Black Holes
• Brown Dwarfs