Wednesday, June 25, 2008

Scientists think big impact caused two-faced Mars

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.

If there ever was a civilization on Mars, this would have made mincemeat of it.


Katie said...

I've always been interested by Tom Van Flandern's theory that there was once a small planet between Mars and Jupiter that was destroyed, causing the damage to Mars that is mentioned, as well as the asteroid belt.

But Ceres located within the asteroid belt, I don't know whether that theory really has that much creedence.

Your thoughts, Mac? I don't seem to recall you ever addressing this theory before...

Mac said...

I'm undecided. I like Van Flandern's hypothesis because, ultimately, it's testable. But a big stumbling block is coming up with a mechanism that can cause a planet to explode.