Calculateur de Densité Baryonique
Calculez la densité de matière baryonique dans l'univers.
Baryon Density Parameter
0.044351
Baryon Density Parameter vs Baryon Density
Formule
Baryon Density Parameter
Ordinary (baryonic) matter—protons, neutrons, electrons—makes up only a small fraction of the universe.
Formula
Omega_b = rho_b / rho_crit
Current measurements give Omega_b about 0.049, meaning only roughly 5% of the total energy budget is ordinary matter.
Exemple Résolu
rho_b = 4.2e-28 kg/m³, rho_crit = 9.47e-27 kg/m³.
- 01Omega_b = rho_b / rho_crit
- 02Omega_b = 4.2e-28 / 9.47e-27
- 03Omega_b ≈ 0.0443
- 04As a percentage: 4.43%
Questions Fréquentes
What counts as baryonic matter?
All matter made of protons and neutrons: stars, planets, gas, dust, and diffuse intergalactic plasma. Electrons are included by convention.
Where is most of the baryonic matter?
Most is in the warm-hot intergalactic medium (WHIM) between galaxies. Only a small fraction is in stars and planets.
How is Omega_b measured?
Primarily from Big Bang nucleosynthesis abundances (deuterium, helium) and the acoustic peaks of the cosmic microwave background.