APOD 1.5-Dry Ice Pits on Mars

Part of Mars is melting, causing dry ice pits to form on the surface of our 'sister' planet. Dry ice pits are formed when carbon dioxide dry ice sublimates straight into gas. Pits are about 150 meters across and lie usually in ancient martian volcanos. On earth, pits are similar to Hawaiian volcano pit craters. When the summer comes, the dry ice pits form and when winter returns, the chilly will stop the defrosting and freeze more layers of solid carbon dioxide.