Dark Matter
Hypothetical matter that does not emit light but exerts gravitational effects on visible matter.
Definition
Dark matter is a hypothetical form of matter that does not interact with the electromagnetic force (so it does not absorb, emit, or reflect light) but is inferred to exist from its gravitational effects on visible matter, radiation, and the large-scale structure of the universe. It is estimated to constitute about 27% of the universe's total energy content. Multiple independent lines of evidence support its existence, though its fundamental nature remains unknown.
Example
“Stars at the outer edges of the Milky Way orbit the galactic center faster than they should based on the visible matter present; dark matter distributed in a halo around the galaxy provides the additional gravitational mass needed to explain these high orbital speeds.”
Synonyms
- invisible matter
- non-baryonic matter
- gravitational dark matter
Antonyms / Opposites
- dark energy
- baryonic matter
- luminous matter