> There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable.

> There is another theory which states that this has already happened.

― Douglas Adams, The Restaurant at the End of the Universe

The probability of a bubble nucleation from false vacuum decay[1] is astronomically low, but the probability that it has already happened is still non-zero. If it did happen we would never know, but if it reached us then we would all be destroyed in an instant.

[1] https://en.wikipedia.org/wiki/False_vacuum_decay