Red Planet Day is observed every year on November 28 to commemorate a turning point in humanity's quest to understand Mars. On this day in 1964, NASA launched the Mariner 4 spacecraft, the first ...

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

"Mars is still the Red Planet. It’s just that our understanding of why Mars is red has been transformed." When you purchase through links on our site, we may earn an affiliate commission. Here’s how ...