An artistic representation, created from simulations, of the impact that gouged out a hole 5,200 miles (8,500km) across and 6,500 miles (10,600km) long in Mars. The giant crater made by an asteroid or comet explains why Mars is so lopsided, with a basin on one hemisphere and high terrain on the other, three separate teams of scientists said on June 25, 2008. [Agencies]