Asteroids: We Aren't Prepared

NASA is looking, and does find asteroids. Unfortunately their efforts are far from comprehensive, and our planet is woefully under-prepared relative to our technical capabilities. A few months back New Scientist published what will hopefully be a wake-up call to politicians globally:

The asteroid is on a collision course with Earth. It is the size of a skyscraper and it's big enough to raze a city to the ground. Oh, and it will be here in three days.

Far-fetched it might seem, but this scenario is all too plausible. Certainly it is realistic enough that the US air force recently brought together scientists, military officers and emergency-response officials for the first time to assess the nation's ability to cope, should it come to pass.

They were asked to imagine how their respective organisations would respond to a mythical asteroid called Innoculatus striking the Earth after just three days' warning. The asteroid consisted of two parts: a pile of rubble 270 metres across which was destined to splash down in the Atlantic Ocean off the west coast of Africa, and a 50-metre-wide rock heading, in true Hollywood style, directly for Washington DC.

The exercise, which took place in December 2008, exposed the chilling dangers asteroids pose. Not only is there no plan for what to do when an asteroid hits, but our early-warning systems - which could make the difference between life and death - are woefully inadequate.

This graphic shows the areas in space that NASA checks for incoming asteroids. To be fair, these zones are where most would be likely to arrive from, but it is well short of the desired coverage:

Our chance of having any prior warning at all for an approaching 30-metre asteroid is no better than 25 to 35 per cent with existing sky surveillance, calculates astronomer Alan Harris of the Space Science Institute in Boulder, Colorado (see graphic). The sun washes out half of the sky with daylight, blinding us to 50 per cent of threatening objects. Even glare from the moon can hide unwelcome incoming guests.

What's more, two of the world's three leading asteroid surveys are based in Arizona, including the Catalina Sky Survey, which discovered 2008 TC3. The region tends to cloud over between July and September...

Read more about asteroids and comets in 2012

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