Hartle–Hawking state

The Hartle–Hawking state is a proposal in theoretical physics concerning the state of the universe prior to the Planck epoch. It is named after James Hartle and Stephen Hawking.

According to the Hartle–Hawking proposal, the universe has no origin as we would understand it: before the Big Bang, which happened about 13.8 billion years ago, the universe was a singularity in both space and time. Hartle and Hawking suggest that if we could travel backwards in time towards the beginning of the universe, we would note that quite near what might have been the beginning, time gives way to space so that there is only space and no time.