Monday, November 01, 2010

"The Asteroid that Flattened Mars": a warning for Terra Firma?

SpaceRip has a “Cosmic Journeys” video “The Asteroid that Flattened Mars”, by Thomas Lucas and Dave Brody. The 21-minute film, interrupted by two commercials, gives a history of our knowledge of Mars, starting with Lowell, going into the 1960s when we knew that Mars was a desert, and the 1976 Viking lander with attempts to find life, that had even attracted comment by Dan Fry and Understanding at a 1978 “Man in Space” convention in Arizona.

More recent probe have provided elevation maps of Mars, show in the film in “World Book” fashion with the lowest elevations in blues and greens and the highest in red. The southern hemisphere is much higher than the northern, a fact which the film says leads to the theory that Mars was smacked by a large asteroid early in its history. The asteroid impact seems to have destroyed most of Mars’s magnetic field, causing it to lose most of its atmosphere and become a dry and cold place. In a sense, this seems like a tragedy, possibly depriving us of a planetary neighbor that could have evolved a civilization comparable to our own. (Maybe that protects us from potential competitors or enemies, depending on how you look at things.)

The implication, of course, is that a large enough asteroid strike on Earth might cause not only a “nuclear winter” but also the loss of its magnetic field, or at least a major shift.

National Geographic has a story by Ker Than, May 11, 2009, that corroborates this theory, "'Supergiant' Asteroid Shut Down Mars's Magnetic Field", link here.

Picture: I doubt you can find such accommodations on Mars now.

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