MIAMI (CBS4) – Everybody knows an iceberg sank the Titanic a hundred years ago next month.  But now scientists are blaming an unexpected culprit for putting that iceberg in the unsinkable ship’s path: the moon.

A century later, the mystery remained as to why one of the most experienced and careful captains in the world, Edward Smith, ignored warnings that icebergs were in the area.

Greenland icebergs, such as the one that sunk the Titanic, generally get stuck in shallow waters off Labrador and Newfoundland, and can’t move south until they melt and get smaller.

So how did all those big icebergs end up threatening the great ship?

Research in next month’s “Sky and Telescope” magazine points to a once in many-lifetimes event three months before the Titanic sailed.

The moon’s approach to the earth was the closest in more than a millennium, and it lined up with the sun, creating phenomenally high tides that separated a large number of fully grown icebergs from Greenland, sending them toward shipping lanes.

The captain had no reason to believe that was possible.  That terrible miscalculation and the bizarre astronomical coincidence combined to cause one of the great tragedies in human history.