Wednesday, July 29, 2009

Jupiter just took a pounding, Is Earth next?

Since the huge impact on Jupiter is still fresh in our memories, I think it's fair to ask - what are the chances that the same could befall Earth any time in the near future?

Tim Sayell send in a good article from Yahoo News that deals with just such a question.

As the article points out: So far 784 near-Earth objects (NEOs) more than a half-mile wide (1 km) have been found. NASA has ruled out any of these as an impactor.

It's a safe bet that if 'an object of about the same size that just hit Jupiter also hit Earth — it was probably a typical cometary object of a kilometer or so in size (0.6 miles) — it would have been fairly catastrophic,'

Currently just one NEO poses any significant chance of hitting the Earth — 2007 VK184. This object is 425-foot-wide and should it hit Earth, it would strike with an energy of more than 10,000 times that of Hiroshima. 2007 VK184 has a 1-in-2,940 chance of hitting Earth 40 to 50 years from now.

Like the mosquito that you don't hear, it's the NEOs that we don't know about that are most worrying. NASA estimates that there are about 156 large NEOs 1 kilometer in diameter or larger that remain to be found. But the truly disturbing statistic is that objects of about 500 feet are extremely dangerous and only about 15% of these object have been discovered and only 5% of objects 150 feet in size.

Now the nitty gritty:
The dinosaur killers happen about once every 100 million years
Impacts of 1500 foot size hits about once every 500,000 nothing is expected soon...
150 feet, about 700 years, 98 feet about 140 years or so.

So, nothing really worrisome with what we know so far....but a lot more has to be put into discovery and tracking before I feel safe.

Read the complete article here

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