doomsday event

The universe will contract and grow hotter until the doomsday event that astronomers have dubbed "the big crunch."

A mysterious occurrence late in the story is the historically factual Tunguska Event, a massive Siberian explosion, probably by an asteroid, in the summer of 1908: a doomsday event caused by an arrival from another realm.

Protect them against molestation, but if it happens, don't overact and inflate it into a doomsday event.