When1: -13720000000
Who: density fluctuations
What: beginning
Where: Universe
Detail: About 1000 seconds after universe origin, temperature was 10^9 K. Universe diameter was 100 light-years. 25% of protons were in helium. Lithium-7 nuclei had 10^-10 of protons. Hydrogen, deuterium, and tritium nuclei were 75% of matter. Helium was 25% of matter. Lithium was 0.0000000001% of matter. Matter and energy density was 0.9 g/cm^3. Photons interacted with free electrons {coupling of matter and radiation} {Thomson scattering}. Electromagnetic force was dominant over gravity and pressure, so photons were like viscous fluid, allowing universe density fluctuations {density fluctuations}, which persisted.
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Date Modified: 2022.0224