Dark Matter
A non-baryonic form of matter that does not absorb, reflect, or emit electromagnetic radiation, detectable solely through its gravitational effects.
Governing formula
Ω_dm ≈ 0.27 (27% of total cosmic mass-energy)
SI unit
M_☉ or kg (Cosmological Density)
In depth
Accounts for approximately 85% of total matter in the universe. Inferred from flat galactic rotation curves, gravitational lensing of galaxy clusters, and cosmic microwave background anisotropy power spectra. Modeled as Weakly Interacting Massive Particles (WIMPs).
Examples in the real world
Galactic rotation curves maintaining flat outer velocities due to surrounding spherical dark matter halos.