Planck Universe

In physical cosmology, the Planck epoch (or Planck era) is the earliest period of time in the history of the universe, from zero to approximately 10−43 seconds (Planck time ). It is believed that, due to the extraordinary small scale of the universe at the time, quantum effects of gravity dominated physical interactions. During this period approximately 13.8 billion years ago gravitation is believed to have been as strong as the other fundamental forces, and all the forces may have been unified. Inconceivably hot and dense, the state of the universe during the Planck epoch was unstable, tending to evolve, giving rise to the familiar manifestations of the fundamental forces through a process known as symmetry breaking. This has also been theorized to be the earliest moment of time that can be meaningfully described.

Modern cosmology now suggests that the Planck epoch may have inaugurated a period of unification, known as the grand unification epoch, and that symmetry breaking then quickly led to the era of cosmic inflation, the Inflationary epoch, during which the universe greatly expanded in scale over a very short period of time.