Solar Wind
Mars lost most of its magnetic field about four billion years ago. As a result, solar wind and cosmic radiation interacts directly with the Martian ionosphere. This keeps the atmosphere thinner than it would otherwise be by solar wind action constantly stripping away atoms from the outer atmospheric layer. Most of the historical atmospheric loss on Mars can be traced back to this solar wind effect. Current theory posits a weakening solar wind and thus today's atmosphere stripping effects are much less than those in the past when the solar wind was stronger.
Read more about this topic: Climate Of Mars
Famous quotes containing the words solar and/or wind:
“Lincoln becomes the American solar myth, the chief butt of American credulity and sentimentality.”
—H.L. (Henry Lewis)
“This girl borrowed no dim light of a star
Nor ever night held her in a dark mesh,
A slim bloom she stood of the first larkspur,
A wind of spring fluttered in her white flesh.”
—Allen Tate (1899–1979)