The impact of a giant asteroid could explain why Mars has two very different faces ? but only if it struck the planet with a glancing blow, computer simulations suggest.
A longstanding puzzle about Mars is why its northern and southern hemispheres are so different. The northern hemisphere is much flatter and lies lower than the southern hemisphere, with a difference in elevation between the two of about 5 kilometres.
In the 1980s, scientists suggested a giant impact by an asteroid about 300 kilometres across in Mars's early history could have led to a permanent depression in the planet's northern hemisphere.
Now, two teams of scientists have created the first computer simulations testing whether such an impact could have produced the observed differences.
For the full article
Click Here .
