Thursday, December 04, 2008

Could Jupiter's Gravity End Life on Earth?

Reading in a recent Daily Galaxy article: Scientists are saying that the planet Mercury could possibly smash into our planet. Jacques Laskar of the Paris Observatory and Gregory Laughlin of the University of California, Santa Cruz reached the same unsettling conclusion using separate computer simulations of long-term planetary motion. Leading them both to conclude that the Solar System is not as stable as once thought.

Specifically, both teams found that Jupiter's gravity could eventually make Mercury's orbit so out of round that it overlaps with the path of Venus.

Their models show that Mercury would be forced into one of four unpleasant scenarios if its orbit were disturbed. Either Mercury will 1: crash into the Sun, 2: be ejected from the solar system altogether 3: crash into Venus or worst case Mercury will crash into Earth.

Such an impact would kill all life on our planet. Nothing would survive. By contrast, the asteroid that doomed the dinosaurs 65 million years ago was likely just 6 miles in diameter; Mercury is 3,032 miles across. The last time an object about that size hit the Earth, the resulting debris formed our Moon.

Even Mars might not be left out of the mix. Most simulations show Mars being pushed into a much colder and farther orbit or ejected as well.

The one saving grace to these scenarios is that the time frame for everything to fall into place in on the order of billions of years, making it more likely that Sol would go well off main sequence and become a red giant before Mercury becomes a problem.

<- more at Sky and Telescope ->

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