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:
“Senta: These boats, sir, what are they for?
Hamar: They are solar boats for Pharaoh to use after his death. They’re the means by which Pharaoh will journey across the skies with the sun, with the god Horus. Each day they will sail from east to west, and each night Pharaoh will return to the east by the river which runs underneath the earth.”
—William Faulkner (1897–1962)
“When we think of him, he is without a hat, standing in the wind and weather. He was impatient of topcoats and hats, preferring to be exposed, and he was young enough and tough enough to enjoy the cold and the wind of those times.... It can be said of him, as of few men in a like position, that he did not fear the weather, and did not trim his sails, but instead challenged the wind itself, to improve its direction and to cause it to blow more softly and more kindly over the world and its people.”
—E.B. (Elwyn Brooks)