The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, ...

In the 1960s, humans set out to discover what the red planet has to teach us. Now, NASA is hoping to land the first humans on ...

By Ashley Strickland, CNN (CNN) — Data from a retired NASA mission has revealed evidence of an underground reservoir of water deep beneath the surface of Mars, according to new research.