Gemini, a constellation and the third sign of the zodiac. The name in Latin means the twins. The constellation contains several relatively bright stars. Castor and Polluxthe two brightest starsare named after two brothers of Greek and Roman legend. In northern latitudes, Gemini is visible in the evening during the winter and early spring.
It's tough to wrap your mind around a time when the Earth wasn't here. So how do Earth and the rest of the planets out there get their start in the universe?
A billion years ago, the moon stopped being geologically active. But that's not to say that the moon is doing nothing for us. Let's find out why we owe our moon some thank-yous.