On the Red Planet, the clouds are not just water ice like on Earth, but can also be made of dry ice. Most of the thin ... and was sure at first it was some color artifact,” Mark Lemmon, an ...

For the fourth year in a row, iridescent clouds of frozen CO2 are lighting the Martian sky. The clouds appear in the same ...

The clouds, known as noctilucent or twilight clouds, contain frozen carbon dioxide, or dry ice. They are tinted with colors when the setting Sun scatters light. That color has led to them being ...