MACHO

Definition

MACHO stands for Massive Compact Halo Object, a type of astronomical body hypothesized to make up dark matter in the galactic halo. MACHOs can include objects like black holes, neutron stars, brown dwarfs, and unassociated planets.

5 Must Know Facts For Your Next Test

1. MACHOs are considered as one potential explanation for the missing mass in galaxies attributed to dark matter.
2. They are difficult to detect because they do not emit significant light or radiation.
3. Gravitational lensing is a key method used to identify MACHOs by observing their effect on light from background stars.
4. The presence of MACHOs was first suggested in the 1980s as an alternative to WIMPs (Weakly Interacting Massive Particles) for explaining dark matter.
5. Surveys such as the MACHO Project and EROS have provided evidence that MACHOs may only account for a small fraction of the dark matter.

Related terms

WIMP: Weakly Interacting Massive Particle, another candidate proposed to explain dark matter.

Gravitational Lensing:

The bending of light caused by massive objects between the observer and a distant source.

Dark Matter:

A form of matter that does not emit light or energy, inferred from its gravitational effects on visible matter.