Celebrate your love for the planet we call home with these free Earth Day coloring pages for kids and adults. Print them for ...

The story of the red planet, it turns out, may be due for a revision. At one time, experts thought that Mars was covered with ...

Before plants ruled, Earth may have glowed violet. The first life forms used retinal instead of chlorophyll, absorbing green light and reflecting red and blue—turning the planet an eerie purple.

Neptune often looks slightly different in observations, as it has dark spots which appear periodically. But it can also be bright at times, as the observations of auroras there show: In the image ...