Asteroid Tsunamis Not So Bad After All?

A new computer simulation has determined that if a 200 metre wide asteroid lands in the ocean, where the water depth is 5 kilometres, the following will occur:

• Initial tsunami with a height of hundreds of metres
• The height of the waves makes them prone to collapse, and they start breaking immediately
• After they are 30 kilometres from the impact site, they have shrunk to a height of less than 60 metres
• Extrapolating the shrinkage suggests a height of less than 10 metres after it has travelled 1000 kilometres

Ultimately, how close to the shore the impact is would make a big difference...

Although 10 metres would ordinarily mean massive devastation, apparently the wavelength would be shorter (2 minutes), and therefore not as damaging as regular tsunamis (8 minutes). The results of another simulation "suggest much slower wave decay", ie worse.

The article concludes with something we all, perhaps, should keep in the back of our mind:

Brian Toon of the Universityof Colorado in Boulder says we should continue surveying for asteroids. "We probably have quite a while before we're going to get hit by a significantly sized [asteroid]," he says. "But nevertheless one of these is going to come at us."

Planet X & Asteroids - They Will Be Found!

There has a been a lot of talk about how an uncharted asteroid, or even Planet X, could do us harm in 2012. The problem is that these predictions are hard to prove or disprove - we don't have good enough telescopes.

This is all about to change with the Aug 2007 launch of Pan-STARRS in Hawaii. Over 4x bigger than any other telescope camera, it will photograph three-quarters of our sky by 2010.

Until now roughly 600,000 asteroids have been catalogued. By 2012 that might reach 1 million thanks to the new telescope.

It will also find any new planets that might be out there, having the ability to locate Jupiter-size planets up to 1700AU from the sun, and Pluto-sized planetoids up to 250AU away. As a comparison, Pluto is between 29-49AU from the sun. The director of the operation said "If Nemesis is out there, we will find it".

Source: New Scientist, 15 Dec 2007