🎛 Parameters

Baryon density Ω_bh² 0.022 Time 1.0 s Speed 1×

📐 Abundances

Temperature

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n/p ratio

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He-4 Y_p

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D/H (×10⁵)

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He-3/H (×10⁵)

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Li-7/H (×10¹⁰)

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Proton (p)

Neutron (n)

Deuterium (D)

Helium-3 (³He)

Helium-4 (⁴He)

Lithium-7 (⁷Li)

ℹ️ About

Big Bang Nucleosynthesis (BBN) occurred in the first ~20 minutes after the Big Bang. Neutrons and protons combined to form deuterium, helium-3, helium-4, and lithium-7. The n/p ratio froze out at ~1/7 when T ~ 0.8 MeV (t ≈ 2s). ~25% of all baryonic mass became helium-4 — a cornerstone of modern cosmology. The baryon density Ω_bh² controls the final abundances.