Mars, Venus, Jupiter and Saturn should be visible to the naked eye, but get a telescope and you can spot Neptune and Uranus.

Earth is home to some truly bizarre and breathtaking landscapes — here are 20 that look straight out of an alien world.

The Mars Express orbiter launched to the Red Planet. Twenty years later, ESA has delivered a high resolution color image of Mars along with a time-lapse of "webcam" images that were released in near ...

A U.S. scientist searching for a civilization across 7 Earth clones circling the red dwarf star TRAPPIST-1 says its own alien ...

Though it's a cold, dead planet, Mars still has its own natural beauty about it. This image shows us something we'll never see on Earth.

Harvard scientists explain how Mars had warm spells billions of years ago, allowing rivers and lakes to exist.

The 3.7-billion-year-old formations in the planet's Gale Crater suggest the presence of long-gone bodies of liquid water, with no ice covering the surface ...

Thousands of mysterious clay mounds found on Mars were formed by ancient water on the Red Planet's barren northern plains, ...

Buttes and mesas in Mars' Chryse Planitia contain clay minerals made from liquid water interacting with the rock nearly 4 ...

Images of Mars taken from orbit show thousands of mounds in a region sculpted by water billions of years ago. A robotic ...

On Jan. 25, 2004, NASA’s Opportunity rover landed on Mars and sent its first pictures of the planet to Earth; originally planned as a 90-day mission, the rover remained operational for over 15 years, ...

The car-sized Curiosity rover has spotted evidence of once quite hospitable environs on Mars.