Kostenloser Matter Density Parameter Rechner
Berechnen Sie Omega_m, the fraction of the critical density in matter. Kostenloser cosmology Rechner.
Matter Density Parameter (Omega_m)
0.279831
Matter Density Parameter (Omega_m) vs Matter Density (rho_m)
Formel
How the Matter Density Parameter Is Found
The density parameter Omega_m tells us the fraction of the universe's critical density that is in the form of matter.
Formula
Omega_m = rho_m / rho_crit
If Omega_total = 1 the universe is geometrically flat. Current measurements give Omega_m about 0.31.
Lösungsbeispiel
With rho_m = 2.65e-27 kg/m³ and rho_crit = 9.47e-27 kg/m³.
- 01Omega_m = rho_m / rho_crit
- 02Omega_m = 2.65e-27 / 9.47e-27
- 03Omega_m ≈ 0.2799
Häufig Gestellte Fragen
Does this include dark matter?
Yes. The matter density parameter includes both baryonic (ordinary) matter and dark matter. About 85% of Omega_m is dark matter.
What happens if Omega_total exceeds 1?
An Omega greater than 1 implies a positively curved (closed) universe that may eventually re-collapse. Observations show Omega is very close to 1.
How is the critical density determined?
It depends on the Hubble constant: rho_crit = 3 H0² / (8 pi G). Different H0 values give slightly different critical densities.