The very early universe

Outline

For the purposes of this summary, it is convenient to divide the chronology of the universe since it originated, into five parts. It is generally considered meaningless or unclear whether timeexisted before this chronology:

The very early universe – the first picosecond (10⁻¹²) of cosmic time. It includes the Planck epoch, during which currently understood laws of physicsmay not apply; the emergence in stages of the four known fundamental interactions or forces – first gravity, and later the strong, weak and electromagnetic interactions; and the expansion of space and supercooling of the still immensely hot universe due to cosmic inflation, which is believed to have been triggered by the separation of the strong and electroweak interaction.

Tiny ripples in the universe at this stage are believed to be the basis of large-scale structures that formed much later. Different stages of the very early universe are understood to different extents. The earlier parts are beyond the grasp of practical experiments in particle physics but can be explored through other means.