Question

what is dark matter?

Answer 1

Dark matter is an unidentified type of mattercomprising approximately 27% of the mass and energy in the observable universethat is not accounted for by dark energy, baryonic matter (ordinary matter), and neutrinos.The name refers to the fact that it does not emit or interact with electromagnetic radiation, such as light, and is thus invisible to the entireelectromagnetic spectrum Although dark matter has not been directly observed, its existence and properties are inferred from its gravitational effects such as the motions of visible matter, gravitational lensing, its influence on the universe's large-scale structure, and its effects in the cosmic microwave background.

Answer 2

a hypothetical form of matter invisible to electromagnetic radiation, postulated to account for gravitational forces observed in the universe.