Long ago, from nowhere, a pinpoint of intensely hot, immensely dense energy appeared.This tiny singularity seeded our entire Universe. Conditions were so extreme we have only the idea of the physics at the start of time.
With the young universe cooling fast and space expending at close to the speed of light, first photons, then quarks and leptons condensed out of the fizzing quantum vacuum like mist on a cold window to form a quark-gluon plasma sea.
Next, after one millionth of a second, the quarks combined into hadrons, primarily protons and neutrons, while vast amounts of matter and antimatter wiped each other out leaving only a billionth of the original material, along with vast quantities of gamma rays. Roughly a second after the birth of the universe its temperature dropped enough to crystallize whizzing neutrinos from the the photons.The universe was expanding incredibly fast and after two hours there was no longer the density of neutrons to allow any heavier nuclei to form.
When the universe was 377,000 years old it finally became coo enough for electrons to settle in orbits around atomic nuclei, and for the next 100 million years everything remained dark as the vast ionized cloud of hydrogen and helium expanded. Eventually, however, the photons were set free from the plasma , the heavens became transparent , and the infant Universe was unveiled in all its newborn glory.
image source: google.
