Scientists have come to some agreement on descriptions of events that happened 10−35 seconds after the Big Bang, but generally agree that descriptions about what happened before one Planck time (5 × 10−44 seconds) after the Big Bang are likely to remain pure speculation.
If inflation has indeed occurred, it is likely that there are parts of the universe so distant that they cannot be observed in principle, as exponential expansion would push large regions of space beyond our observable horizon.