dark matter

Definitions

1. Matter which cannot be detected by its radiation but whose presence is inferred from gravitational effects.
   broadly, uncountable
2. Matter which has mass but which does not readily interact with normal matter except through gravitational effects.
   particle, uncountable
3. Unclassified or poorly understood genetic material.
   informal, uncountable

Equivalents

Examples

“The evidence for dark matter⟳ in galaxies started to accumulate in the mid-1970s. By the following decade it became clear that essentially all galaxies, including our own⟳ Milky Way, are surrounded by extensive halos of dark matter⟳.”

“On large scales like⟳ that of clusters of galaxies, gravitational lensing indicates that the dark matter⟳ is smoothly distributed, on the average.”

CEFR level