The universe began 13.72 billion years ago {universe history}.
before Planck time
Quantum mechanics and general relativity theorize that universe began with smallest 3-sphere volume, densest energy, highest pressure, greatest space curvature, and highest temperature. Because volume was smallest, universe had lowest entropy. Because temperature and external pressure were highest, space had highest expansion rate (Big Bang).
Before elapsed time was Planck time, 10^-43 seconds, time had quanta, random perturbations, expansions, contractions, and inhomogeneities. Space volume had diameter less than Planck length, 10^-35 meters. Indeterminate space and time dimensions superimposed and interchanged, with no distance metric, so things had indeterminate sizes. Quantized space had random expansions and contractions; tears and joins; loops, handles, holes, nodes, knots, links, kinks, and entanglements; rotations, spins, twists, and windings; phases, boundaries, inhomogeneities, and overlaps; asymmetries, anisotropies, and discontinuities; and relaxations, nonstandard fields, and nonstandard forces. This "quantum foam" was like periodic orbits in chaotic systems.
before Planck time: energy
Total universe energy was same as now. Because space volume was smallest, energy density was highest. Because universe had shortest size and time, by uncertainty principle, universe had highest energy and energy fluctuations. Because many bosons can occupy the same space, even the smallest universe can have any number of high-energy real and virtual bosons and can have any energy level.
before Planck time: temperature and pressure
Because kinetic energy was highest, temperature and pressure were highest. Radiation frequency was highest, so radiation energy and pressure were highest.
after Planck time
From 10^-43 seconds after universe origin (diameter 10^-35 meters) to 10^-39 seconds after (diameter 10^-15 meters), space expansion pushed masses farther apart and increased potential energy, so kinetic energy decreased and universe cooled. Quantum mechanics and general relativity theorize that quantum foam became continuous four-dimensional space-time as universe temperature and pressure decreased. Space, time, energy, and momentum had discrete quanta, and physical processes followed quantum-mechanics and general-relativity laws.
after Planck time: radiation only
Because gravitation, electromagnetism, strong nuclear force, and weak nuclear force differentiate only at lower temperatures, universe had only one unified force. Supersymmetry united bosons and fermions. Because distances were short, potential energy was low, and kinetic energy was high. Because temperature was too hot to allow matter formation, universe had only zero-rest-mass radiation, traveling at light speed at high frequency with short wavelength.
after Planck time: physical laws
Universe had special relativity, general relativity, and quantum mechanics. Because universe had only radiation, universe had no particles and so no particle Standard Model. Because forces had not yet differentiated, universe did not have quantum electrodynamics or quantum chromodynamics. Energy, momentum, and angular momentum conservation began.
cosmic inflation
After 10^-39 seconds after universe origin, space expansion rate became extra-fast for less than one second, after which time it returned to regular space expansion rate.
particle formation
After that, protons, neutrons, and electrons formed, and then helium atomic nuclei formed.
atom formation
When universe was 300,000 years old, neutral-charge hydrogen and helium atoms formed, leaving 3000-K (visible-wavelength) radiation.
galaxies
Between 12 and 9 billions years ago, galaxies formed, and since then supernovas have made carbon, oxygen, and other atomic nuclei.
now
Now, universe has 400 billion galaxies, about 3 million light-years apart, averaging 100 billion stars. Universe has more than 100 billion planets.
Universe has 75% hydrogen nuclei and atoms and 25% helium nuclei and atoms.
The 3000-K radiation has become 3-K (microwave) radiation, streaming almost uniformly from all space directions, proving that universe began hot and then space expanded.
future
One hundred fifty billion years from now, recession velocity of the galaxy cluster nearest to the Milky Way Galaxy (in the Virgo Cluster) will exceed light speed. Light from galaxy-cluster stars (small ones will still be shining) will have red-shifted to frequency 5000 times lower. Cosmic microwave background radiation will have temperature near absolute zero.
Two trillion years from now, recession velocity of the very-small-so-still-shining stars closest to the sun will exceed light speed, and its light will have red-shifted to frequency near zero, so those photons will have lowest energy, and cosmic microwave background radiation will have temperature essentially absolute zero.
Much longer than two trillion years from now, solar system, earth, and molecule particles and radiation will spread apart to almost infinite distances, and universe will have absolute zero temperature.
Physical Sciences>Astronomy>Universe>Cosmology
5-Astronomy-Universe-Cosmology
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Date Modified: 2022.0224