The Planck epoch
The first ten-millionth of a trillionth of a trillionth of a trillionth of a second — and the edge of physics.
- When
- Known to
- ± 20 million years
- Era
- Primordial
For roughly the first 10⁻⁴³ seconds the universe is so dense that gravity is as strong as the other three forces, and general relativity and quantum mechanics both apply where neither can be trusted. This is not a gap in the record but a limit of the theory: describing it needs a theory of quantum gravity that does not yet exist. Everything before this boundary is honestly unknown rather than merely unobserved.