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)
“Those craning birds are choice for you, songs that jump back
To the built voice, or fly with winter to the bells,
But do not travel down dumb wind like prodigals.”
—Dylan Thomas (1914–1953)