http://news.yahoo.com/s/ap/20080625/ap_on_sc/sci_two_faced_mars
LOS ANGELES - Why is Mars two-faced? Scientists say fresh evidence supports
the theory that a monster impact punched the red planet, leaving behind perhaps the largest gash on any heavenly body in the solar system.
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Today, the Martian surface has a split personality. The southern hemisphere of Mars is pockmarked and filled with ancient rugged highlands. By contrast, the northern hemisphere is smoother and covered by low-lying plains.
Three papers in Thursday's journal Nature provide the most convincing evidence yet that an outside force was responsible.
According to the researchers, an asteroid or comet whacked a young Mars some 4 billion years ago, blasting away much of its northern crust and creating a giant hole over 40 percent of the surface.
LOS ANGELES - Why is Mars two-faced? Scientists say fresh evidence supports
the theory that a monster impact punched the red planet, leaving behind perhaps the largest gash on any heavenly body in the solar system.
ADVERTISEMENT
Today, the Martian surface has a split personality. The southern hemisphere of Mars is pockmarked and filled with ancient rugged highlands. By contrast, the northern hemisphere is smoother and covered by low-lying plains.
Three papers in Thursday's journal Nature provide the most convincing evidence yet that an outside force was responsible.
According to the researchers, an asteroid or comet whacked a young Mars some 4 billion years ago, blasting away much of its northern crust and creating a giant hole over 40 percent of the surface.
