Cosmology Concepts
38 entries in the Cosmology Concepts compendium.
Accelerating expansion of the universeDiscovery that the universe's expansion is speeding up, not slowing down.Age of the universeAge of the universe is 13.8 billion years.Alpher–Bethe–Gamow paperThe αβγ paper on Big Bang nucleosynthesis, authored by Alpher and Gamow only.Anthropic principleObservable universe must allow observers to exist.BaryogenesisHypothesized process producing matter dominance over antimatter in the early universe.Baryon acoustic oscillationsStandard ruler from early universe sound waves.Big Bang nucleosynthesisModel for light nuclei formation in the early universe.Big CrunchA scenario where the universe collapses back to a singularity.Big RipA model where dark energy tears apart all matter.Chronology of the universeStandard timeline of cosmic history from inflation to present.Comoving and proper distancesTwo distance measures used in standard cosmology.Cosmic neutrino backgroundRelic neutrinos from one second after the Big Bang.Cosmological horizonBoundaries dividing observable from unobservable regions of the universe.Cyclic modelCyclic models propose an infinite series of cosmic expansions and contractions.Discovery of cosmic microwave background radiationThe discovery of cosmic microwave background radiation reshaped modern physical cosmology.Electroweak epochEpoch when electromagnetism and weak force were unified.Expansion of the universeThe increase in distance between gravitationally unbound parts of the universe.Grand unification epochEarly universe epoch unifying three fundamental forces.Horizon problemA cosmological fine-tuning problem in the Big Bang model.Lambda-CDM modelStandard cosmological model of dark energy and cold dark matter.Lepton epochEpoch when neutrinos decoupled and leptons dominated the plasma.Missing baryon problemMissing baryons are baryonic matter not yet observed in the recent universe.MultiverseHypothetical set of all universes, debated in science and philosophy.Observational cosmologyStudy of the universe through observation and measurement.Particle horizonBoundary between observable and unobservable regions of the universe.Photon epochEpoch when photons dominated the early universe's energy.Physical cosmologyStudy of the universe's origin, structure, and evolution.Primordial fluctuationsDensity variations seeding all cosmic structure.Quark epochEarly universe period when quarks existed freely in a plasma.Recombination (cosmology)Epoch when electrons and protons first formed neutral hydrogen atoms.RedshiftRedshift measures the stretching of light from moving or distant sources.ReionizationReionization transformed neutral hydrogen into ionized plasma after the Dark Ages.Scale factor (cosmology)Dimensionless parameter describing the expansion of the universe.Shape of the universeThe universe's shape involves local curvature and unknown global topology.Steady-state modelA now-rejected cosmological model with continuous matter creation.Structure formationProcess creating galaxies and voids from density ripples.Ultimate fate of the universeScientific hypotheses predict the universe's possible end.UniverseThe totality of all space, time, matter, and energy.
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