BBN
E125208
BBN is the early-universe process that produced the lightest elements—mainly hydrogen, helium, and small amounts of lithium—within the first few minutes after the Big Bang.
All labels observed (1)
| Label | Occurrences |
|---|---|
| BBN canonical | 1 |
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
Big Bang nucleosynthesis
ⓘ
cosmological process ⓘ |
| alsoKnownAs | primordial nucleosynthesis ⓘ |
| assumes |
homogeneous and isotropic universe
ⓘ
standard model of particle physics ⓘ |
| beginsWhen | temperature drops below about 1 MeV ⓘ |
| category |
nuclear astrophysics
ⓘ
physical cosmology ⓘ |
| constrains |
baryon density of the universe
ⓘ
cosmological parameters ⓘ effective number of neutrino species ⓘ |
| dependsOn |
baryon-to-photon ratio
ⓘ
expansion rate of the universe ⓘ number of light neutrino species ⓘ |
| distinctFrom |
cosmic-ray spallation
ⓘ
stellar nucleosynthesis ⓘ |
| drivenBy | nuclear reactions in hot dense plasma ⓘ |
| endsWhen | temperature drops to about 0.01 MeV ⓘ |
| follows |
neutrino decoupling
ⓘ
weak interaction freeze-out ⓘ |
| fullName |
big bang nucleosynthesis
ⓘ
surface form:
Big Bang nucleosynthesis
|
| isComplementaryTo | cosmic microwave background measurements ⓘ |
| isIndependentProbeOf | cosmic baryon density ⓘ |
| keyReaction |
deuterium formation from proton and neutron
ⓘ
helium-4 synthesis from deuterium and helium-3 ⓘ proton–neutron interconversion via weak interactions ⓘ |
| mainProducts |
helium
ⓘ
hydrogen ⓘ |
| occursIn | early universe ⓘ |
| precededBy | quark–hadron transition ⓘ |
| predicts |
primordial deuterium abundance
ⓘ
primordial helium-3 abundance ⓘ primordial helium-4 mass fraction of about 25 percent ⓘ primordial lithium-7 abundance ⓘ |
| produces |
deuterium
ⓘ
helium-3 ⓘ helium-4 ⓘ hydrogen-1 ⓘ light elements ⓘ lithium-7 ⓘ trace amounts of other light nuclides ⓘ |
| secondaryProducts | lithium ⓘ |
| sensitiveTo |
new light particle species
ⓘ
variations in fundamental constants ⓘ |
| supports |
Big Bang cosmology
ⓘ
surface form:
Big Bang model
|
| testedBy | observations of primordial element abundances ⓘ |
| timeAfterBigBang |
approximately 1 second to 20 minutes
ⓘ
first few minutes ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Big Bang nucleosynthesis