Constants & Units · constant

Matter density parameter

Ω_m = 0.315 ± 0.007 —

Unit

—

Value

0.315 ± 0.007

Exact

no

Note

All matter, of which only about one sixth is the ordinary kind.

Symbol

Ω_m

Category

Cosmological

Numeric

0.315

Uncertainty

±0.007 (Planck 2018)

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From the Constants database in Notion, last edited 2026-08-15. This page is the row, rendered by the build; nothing on it is written by hand.