A beautiful ballerina and a handsome prince are at the heart of the world's most famous ballets. Sleeping Beauty. Swan Lake. The Nutcracker, of course.

And at training grounds for future dancers, plenty of girls hope to someday wear the prima ballerina's tutu.

But it's become a challenge to find the boys who will one day form the other half of the pas de deux.

'Cooties And Stuff'

The Tidal Dance of the Earth and the Moon

We learn in grade school that the Moon, our nearest neighbor in space, causes tides on the Earth’s oceans. It does so through its gravitational attraction to the Earth. But the gravitation interplay between Earth and Moon has other, subtler effects as well.