Everybody, even those who are complete beginners in the field of Astronomy, know Io, the cryovolcanic moon of Jupiter that looks like a burned pizza with skin cancer. Volcanoes constantly spit out sulphur in various forms and compounds, which gives Io its characteric coloring that consists mainly of yellow, red and orange fields with occasional black or green patches. The pattern can change completely within 2 weeks!
Now, for my SF novel, I want to create a similar celestial body, with one condition: the planet is going to be blue. Light or dark blue with occasional white, black or green patches, with severe cryovolcanism just like Io has.
My questions are:
- What chemical elements or compounds could lead to such a coloring of the planet or moon?
- How could they be created naturally and occur as a part of a cryovolcanic system like Io's?
EDIT: The compounds which color the moon blue should be solid at a temperature of -200 degrees.