The vessel moved through the fog towards some unseen bourne.
Setting forth in an opposite direction, he should get to the same bourne by another route.
Event horizons mark the bourne from which no traveller, even light, can return, because of the intense gravity.
Hamlet describes non-existence as "that undiscover'd country from whose bourn no traveller returns".
The mystery of existence will ever loom beyond the bourne of man's intellect.