... Io, the innermost large moon of Jupiter, is known to be the most tumultuous body in the Solar System. Approximately the size of Earth.. ... Night and Day in Melas Chasma on Mars . ... IC 418: The Spirograph Nebula . ... Meteors Between Stars and Clouds . ... Streaking high above diffuse clouds -- but well in front of distant stars -- are sand-sized bits of an ancient comet: meteors. ... When the Moon's shadow reached out and touched the Earth last week, the result was a solar eclipse. ...