How have astronomers searched for evidence of MACHOs in the halo of the Milky Way?
A) They search for stars that are binary companions of MACHOs.
B) They search for rapidly moving, massive gas clouds.
C) They search for disturbances in the background of gravitational waves.
D) They search for stars whose light is briefly amplified by gravitational lensing.
E) They search for close binary stars undergoing mass transfer.

Question

Quizplus · Accepted Answer

Astronomers search for evidence of MACHOs in the halo of the Milky Way by looking for stars whose light is briefly amplified by gravitational lensing. This is caused by the gravitational field of a MACHO bending and focusing the light of a more distant star. By observing the changes in brightness and duration of this amplification, astronomers can infer the presence and properties of the MACHO.

How Have Astronomers Searched for Evidence of MACHOs in the Halo