Asteroid Apophis is heading towards Earth. It may or may not cause worldwide prayers and panic in the weeks leading up to 13th April 2029 - that remains to be seen. I have seen various odds against a direct hit on our planet ranging from 30/1 to 60/1 and have also read theories that Apophis will pass safely between Earth and Moon (as in this Wiki-photo where the white line is the official margin of error).
I remember how we all watched the TV news for pictures every night fascinated and safely terrified when a comet, Shoemaker-Levy I think, plunged piece by piece, like a broken string of firey beads, into the gas giant Jupiter some years ago.
I also remember drawing a sweepstake ticket for a horse called Foinavon when it won the Grand National, against all predictions, at odds of 100/1.
Blake's God measures the future
with hair blowing in torn sail
ragged in the east wind's gale
with golden dividers fixed at 90°
- the span of his left hand
Circumscribes the universe
with exactness and precision
then leaves Apophis on the way
- neglects to clear the builder's debris
and rests upon the seventh day
an evil snakelike demon