A thousandth of a billionth of a billionth of a second after the presumed origin of space and time, what would one day become the whole of our visible Universe was a sphere ten metres in diameter. At this point, the temperature of the Universe was a few billion billion billion degrees. All the places in the Universe were in contact.
This inflation generated the Cosmological Background, which explains why it is uniform today.
If we try to go further back in time, we can't. Indeed, we are now in the period of the Planck Era.
Indeed, there was no time before the Big Bang. This means that there is no possibility of a creator, because there is no time for a creator to have existed in.
According to the no-boundary proposal, asking what came before the Big Bang is meaningless, like asking what is south of the South Pole, because there is no notion of time available to refer to. The concept of time only exists within our universe.
Timeline
seconds: GUT era Symmetry breaking occurred, creating a rapidly expanding bubble. As the bubble inflated, the four fundamental forces rapidly split off from each other. Gravity was the frst force to be split off from the other three, releasing a shock wave throughout the universe. The original symmetry of the superforce was broken down to a smaller symmetry, perhaps containing the GUT symmetry SU(5). The remaining strong, weak, and electromagnetic interactions were still unifed by this GUT symmetry. The universe inflated by an enormous factor, perhaps 1050, during this phase, for reasons that are not understood, causing space to expand astronomically faster than the speed of light. The temperature was 1032 degrees.
seconds: end of inflation. The temperature dropped to 1027 degrees as the strong force split off from the other two forces.(The GUT symmetry group broke down into SU(3) × SU(2) × U(1). ) The inflationary period ended, allowing the universe to coast in a standard Friedmann expansion. The universe consisted of a hot plasma “soup” of free quarks, gluons, and leptons. Free quarks condensed into the protons and neutrons of today.
3 minutes: nuclei form Temperatures dropped sufficiently for nuclei to form without being ripped apart from the intense heat. Hydrogen fused into helium (creating the current 75 percent hydrogen/25 percent helium ratio found today). Trace amounts of lithium were formed, but the fusion of higher elements stopped because nuclei with 5 particles were too unstable. The universe was opaque, with light being scattered by free electrons. This marks the end of the primeval freball.
380,000 years: atoms are born. The temperature dropped to 3,000 degrees Kelvin. Atoms formed as electrons settled around nuclei without being ripped apart by the heat. Photons could now travel freely without being absorbed. This is the radiation measured by COBE and WMAP. The universe, once opaque and flled with plasma, now became transparent. The sky, instead of being white, now became black
1 billion years: stars condense. The temperature dropped to 18 degrees. Quasars, galaxies, and galactic clusters began to condense, largely as a by-product of tiny quantum ripples in the original freball. Stars began to “cook” the light elements, like carbon, oxygen, and nitrogen. Exploding stars spewed elements beyond iron into the heavens. This is the farthest era that can be probed by the Hubble space telescope.
6.5 billion years: de Sitter expansion. The Friedmann expansion gradually ended, and the universe began to accelerate and enter an accelerating phase, called the de Sitter expansion, driven by a mysterious antigravity force that is still not understood.
13.7 billion years: today. The present. The temperature has dropped to 2.7 degrees. We see the present universe of galaxies, stars, and planets. The universe is continuing to accelerate in a runaway mode