--Was Mars stripped of its protective magnetic field by a huge asteroid impact that left THIS crater as deep as Mount Everest?--

March 5 2013.

Sometimes around 4 billion years ago Mars had a catastrophic encounter with a super-massive 1500 miles wide asteroid, the impact was strong enough to alter the mantle dynamics thus shutting down Mars magnetic field.

The signs are there, Mars is the only planet that is not as "round" as the other planets are. After careful topographic studies of Mars surface you can clearly see the impact point stretching several thousand miles in an elliptical form giving the angle of impact at 30 to 60 degrees.

Here is a false color image of Mars clearly showing the impact crater.



Here is another showing some of the 5 most impressive impacts.



And here is an artists concept of the impact.



The article.

Four billion years ago, Mars had a magnetic field, just like Earth's - but something turned it off, leaving a barren planet totally exposed to the Sun's deadly radiation.

Now scientists have come up with a likely culprit - a huge asteroid impact which left a crater as deep as Mount Everest is high.

That impact, and four other 1500-mile-wide asteroids, had a catastrophic effect on hot rocks in and under Mars's surface - 'knocking out' the planet's magnetic field forever.

[link to www.dailymail.co.uk]

Here is another link.

Giant Asteroid Flattened Half of Mars, Studies Suggest .

[link to www.scientificamerican.com]