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Thursday, June 23, 2005

Why we need a (safe) asteroid hit!


Duck! Posted by Hello

Humanity doesn't really seem to get going and prepare for disasters until the prospect of catastrophe is imminent or, less happily, after the actual experience of a similar event. What we really need, therefore, in order to be better prepared for a major impact is a smaller scale regional devastation from an asteroid that lands in the middle of a huge uninhabited area. This is not ours to command of course but bearing in mind the relative complacency of international governments in the face of an ongoing threat it might be the only thing that saves us from extinction in the longer term.

The NEO (Near Earth Object) asteroid 2004 MN4 will definitely not hit in 2029. Phew! But hang on. Glancing by at a mere 25,600 kilometres (16000 miles), with a diameter of 300 metres and a potential impact velocity of 12.6 kilometres (7.88 miles) per SECOND it's not the sort of object that leaves much room for manoeuvre. Statistics - NASA Moreover, its close shave with earth in 2029 will gravitationally alter its orbit ever so slightly but with a few metres deflection this could easily give a hit the next time round in 2035 or 2036. The truth is that we just won't know what the likelihood of that is until 2029 ... which leaves us just 6 years to try and do something about it.

An impact from 2004 MN4 would leave massive regional devastation but it is not a planet (or even a continent) killer. The best case scenario in the worst case event would be an impact is a deserted corner of the earth (not at sea as this would cause a tsunami). With an eastern hemisphere impact projection that narrows it down to central Australia and Siberia. Any land fall nearer any urban centre is certainly bad news.

With a ground zero, say, in Sydney imagine a crater 6.4 km (4 miles) wide and 500 metres (1625 feet) deep. 5 km (3 miles) out, please take cover from the 10 metres (30 feet) boulders raining down continuously. Expect total hearing loss, (the least of your problems). You won't escape metre sized ejecta until you flee to a distance of 20 km (12 miles). Even 80 km (50 miles) away, glass windows will be blown out. You get the picture. Basically, there would be nothing left of Sydney. Of a population of 4 million people, maybe only a million or even much fewer would survive; severely injured of course and taxing all efforts to locate and treat.

So, with the governments still not taking the dangers of asteroid impacts seriously enough perhaps the kindest thing to happen to humanity would be a hit in 2035 but not in an inhabited area. Perhaps then we might wake up and put more money into Near Earth Object detection and impact prevention.

5 comments:

Huw Raphael said...

We've survived 6 or 7 millennia without even knowing such a thing was possible - although it was. Now that we know it's possible - even though it's no less or more likely to happen - we're supposed to spend money on it?

Heavens but No thank you. Seems rather like fear mongering in order to drum up more taxes.

If we have to spend money at all... hunger would be a good thing, I think. Or, better yet, give the taxes back the masses and let charity begin where it's supposed to begin - with one's neighbour.

Father Gregory said...

Dear Huw

I might accept your argument if my neighbour was unaffected by such things. In fact the Tunguska impact in 1908 http://en.wikipedia.org/wiki/Tunguska_event if moved 600 miles to the south west would have devastated Krasnoyarsk http://tlcom.krs.ru/gallery/f_00.htm

Back in the 6th century we might have had a similar but larger event in Northern Europe ... crop failures and sun darkening all point in this direction.

The future of this research might determine just how many neighbours we have to care for. Some threats require collective preventative action ... not just individual goodwill. This, I believe, is one of them.

Father Gregory said...

I should have givern the link for the Dark Ages story. It's here:-

http://news.bbc.co.uk/1/hi/in_depth/sci_tech/2000/festival_of_science/916421.stm

Ian said...

Living in Sydney [~40 km from the city centre], your use of it as an example certainly brought it home to me.

It does say something rather tragic about us, however, if we need such an event to swing us into action. Then again, it did need a devastating tsunami in SE Asia to get the world looking at early-warning detection there.

Father Gregory said...

Let's hope Ian that "look at" translates eventually into action. The Cascadian fault off the north western coast of the US recently triggered an underwater quake. Fortunately it was a non-tsunami event. Unfortunately the warning system was incapable of reaching down all parts of the vulnerable west coast simply because of a telephony problem. We have to do better than this.

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