NASA's Curiosity rover captures cloudy day on Mars

What they found: This year, NASA commanded Curiosity to keep an eye out for early clouds forming in the planet's atmosphere after spotting them earlier than expected on Mars two Earth years ago.

• When Curiosity did spot early-forming clouds in late January 2021, researchers noticed they were much higher in the atmosphere than typical clouds the rover has seen in the past.
• These January clouds were "wispy puffs filled with ice crystals that scattered light from the setting Sun, some of them shimmering with color," NASA said in a statement.
• As researchers continued to study them, they realized the high altitude clouds were made of frozen carbon dioxide, or dry ice, not water ice, which composes the clouds seen by Curiosity at about 37 miles above the surface.

The big picture: Mars is a popular place these days. Three new missions arrived at the Red Planet this year with plans to study the world from above and from the surface.

• Eventually, NASA hopes to launch a mission to return samples from the planet to Earth in order to study them with cutting-edge tools to learn more about whether Mars once played host to life.