If a big comet passes by and will return in a hundred years and strike your Earth.
According to calculations made at the time, the comet should return around the year 4876.
After 52 years of quiet, the comet returned again.
The comet will actually return to Earth in another few millennia and miss the planet entirely.
However the comet did not return on its expected 11 year path around the sun, and has not been seen since.
The comet would not return for a long time.
Halley's comet has returned twice since Palitzch saw it.
But the comet returned just as he said it would.
Halley's comet has since returned, but no one quite like Jack Johnson ever has.
He predicts that the comet will return again in 1758.