1 / 20
Snow on Mars: NASA Spacecraft Spots 'Dry Ice' Snowflakes
Researchers have calculated that carbon dioxide snow particles on Mars are roughly the size of a human red blood cell. Martian snow is depicted in this artist's rendering as a mist or fog that eventually settles to the surface.

What to Read Next

The surface of Mars

September 17, 2012

Close-up views of our neighboring planet.