Mars is a cold, dry, desert-like planet. But billions of years ago, scientific evidence suggests that it had a thick atmosphere, which kept it warm enough to support flowing water on its surface. So, what happened to the Red Planet, and could it happen to Earth?

Look low on the southwestern horizon at sunset on Nov. 12 for a chance to see swift Mercury close to the red light of Mars in the evening sky, but fair warning — you'll need to be quick to spot the elusive planets before they slip quickly out of sight.

The mission’s two satellites are named Blue and Gold. They will circle Mars from opposite directions and provide a 3-dimensional view of the planet.

From the orbit of Mars, China's Tianwen-1 sent back new and intriguing images of our interstellar visitor. An animation shows it move across the sky.

Siccar Point, photographed by the Curiosity rover, is near Mars' Gale Crater. NASA/JPL-Caltech/MSSS; Processing & License: Kevin M. Gill People from cultures across the world have been looking at Mars since ancient times. Because it appears reddish, it has ...

A deeply golden, even slightly orange handful of fire rises in the dusk each day and spends the entire night crossing low across the south sky. That imposing mass of celestial flame and fame is none other than the most fascinating of all Earth’s fellow ...

A mudstone sample from Jezero Crater shows textures and minerals that on Earth often form through microbial activity. Scientists caution that nonbiological processes could also explain the features, and proof will require Earth-based lab testing.