How can one detect a Massive Compact Halo Object?

Massive Compact Halo Objects (MACHOs) can be detected primarily through gravitational lensing, where their gravitational field bends the light from background stars or galaxies. If a MACHO passes in front of a distant light source, it can cause a temporary brightening or magnification of that source, which can be measured. Additionally, observational methods such as monitoring the motion of stars in a galaxy can help infer the presence of MACHOs by revealing gravitational effects that can't be accounted for by visible matter alone.