MACHOs (Massive Compact Halo Objects)

MACHOs, or Massive Compact Halo Objects, are a proposed type of dark matter candidate consisting of invisible or faint objects like black holes, neutron stars, or brown dwarfs that exist in the outer regions (halo) of galaxies. They are difficult to detect because they emit little to no light, but their gravitational effects can influence the motion of stars and gas. Scientists study MACHOs to understand the composition of dark matter—mysterious matter making up about 85% of the universe's mass—by searching for their gravitational lensing effects on distant light sources.