[meteorite-list] British Study Attempts to Calculate Odds of Being Hit By a Meteorite

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Sun Jul 30 22:16:22 2006
Message-ID: <200607310213.TAA04018_at_zagami.jpl.nasa.gov>

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/07/31/nmeteor31.xml&pPage=/core/Matt/pcMatt.jhtml

What chance of being hit by a meteorite? Don't ask a scientist
By Ben Fenton
The Telegraph (United Kingdom)
July 31, 2006

In the true spirit of the British bureaucrat, scientists at a top secret
atomic energy research centre were ordered to calculate the precise
chances of being killed by a meteorite while out for a stroll.

In 1980, while debates on nuclear safety raged as fiercely as they do
today, Whitehall did not consider it good enough to be able to say that
there was more chance of being killed in a car crash or any form of
natural disaster than falling foul of a Chernobyl-style disaster.

The Health and Safety Executive decided that it was necessary to
calculate the exact chances of a range of deaths that included more
obvious ones, such as being struck by lightning or hit by a runaway train.

But they also thought that, to place the dangers of nuclear reactor
accidents in context, ministers must also be able to refer to the
likelihood of the heavens falling on your head.

So the Safety and Reliability Directorate of the UK Atomic Energy
Authority came up with an equation. It showed that, statistically
speaking, some poor Brit would be squashed by a heavenly body every
7,000 years or so.

Once in every million years, we should expect a meteorite strike that
would kill 500 people, although that would presumably depend on whether
the chunk of celestial debris flattened Oxford Street at lunchtime or
Chewton Mendip on a Sunday morning.

Reassuringly, in a paper released at the National Archives in Kew, the
scientists also produced a table relating the size of meteorites, their
frequency and their "lethal area - the area within which all life is
extinguished by the average meteorite".

This pointed out that eight meteorites of up to 25lb penetrated the
atmosphere each year and if they landed would have a lethal area of the
size of an average city back garden.

But every 80 years or so a meteorite weighing up to a ton breaks through
with a killing zone of 133 acres.

Then, each 100 million years, a meteorite the size of a modest mountain
will hit the earth with a lethal area of, roughly speaking, England.

So, heads down.

But those are just the statistics. The historical record makes rather
more reassuring reading. The only person known to have been hit by a
meteorite was a woman in Sylacauga, Alabama, in 1954. The 8lb rock hurt
her shoulder after crashing through the roof of her house.

All in all, it is probably safest to agree with the atomic scientists
from Risley who concluded that "these data are largely conjectural [and]
it is therefore not possible to determine the reliability of the results
presented herein".

Which sounds a lot like: "Search me!"
Received on Sun 30 Jul 2006 10:13:44 PM PDT