Asteroid slammed into Mars' northern hemisphere

June 27, 2008 An asteroid the size of Pluto that slammed into the Northern hemisphere of Mars created the Borealis basin, based on the latest survey of NASA's Mars Reconnaissance Orbiter and Mars Global Surveyor.

The report released by the magazine Nature explains the 1984 observation of the unusual shape of Mars terrain in the northern hemisphere against the southern hemisphere.

An asteroid with a body of 1,900 kilometers (1,200 miles) smashed into the planet some 3.9 billion years ago, creating the vast Borealis basin (measuring 8,500km [5,300 miles] by 10,600km [6,600 miles] across), which occupies nearly 40 per cent of the Martian surface.

The new data has convinced a lot of scientists, but the theory will need further proof before being accepted by the wider scientific community.