Cancer, a constellation and the fourth sign of the zodiac. Cancer is the Latin name for crab; presumably, the unknown person who named it thought the constellation resembled that animal in shape. The Tropic of Cancer, an imaginary line 23 27' north of the Equator, marks the northernmost points reached by the sun's vertical rays. It is so named because in ancient times the sun was highest in the northern sky when it was in the same area of the sky as Cancer.
Wolves supposedly howl at it, a fairy tale claims a cow once jumped over it and legends say if you look hard enough, there's a man in it. Yes, the moon has a prominent place in popular culture, but there's a lot you might not know about Earth's little orbiting friend. Why doesn't it have soil? Why is its gravity so important? And are we really thinking of going back soon?
We can't defy the odds of an asteroid taking a turn for Earth forever, so the world's astronomers watch the sky. What happens once they spot something?