How have astronomers searched for evidence of MACHOs in the halo of the Milky Way?

Question

Quizplus · Accepted Answer

Astronomers have searched for evidence of MACHOs (Massive Compact Halo Objects) by looking for stars whose light is briefly amplified by gravitational lensing. MACHOs can cause gravitational lensing by passing in front of a background star, bending and magnifying the light from the star, and creating a brief (few days to a few weeks) brightening of the star's light. By monitoring large numbers of stars in the halo of the Milky Way, astronomers can search for such gravitational lensing events and infer the presence of MACHOs in the halo.

How Have Astronomers Searched for Evidence of MACHOs in the Halo