[Infowarrior] - Schoolboy debunks NASA estimate of asteroid threat

[Richard Forno]

Schoolboy debunks NASA estimate of asteroid threat

By Karen Barlow

http://www.abc.net.au/news/stories/2008/04/16/2218782.htm

Posted 8 hours 17 minutes ago
Updated 6 hours 29 minutes ago
An artist's conception of an asteroid crashing into Earth [file photo].

An artist's conception of an asteroid crashing into Earth [file photo].
(Reuters: NASA)

    * Audio: Schoolboy debunks NASA estimate of asteroid threat (The World
Today)

The space boffins do not always get it right - a 13-year-old schoolboy has
successfully challenged NASA, correcting the US space agency's calculations
of a possible killer asteroid strike on the Earth in 30 years.

NASA had estimated there was a one in 45,000 chance that the asteroid
Apophis will collide with the Earth.

But a young German schoolboy, Nico Marquardt, corrected it to a one in 450
chance and therefore changed the date the asteroid might hit.

The work has impressed the head astronomer at the Anglo-Australian
Observatory, Professor Fred Watson.

"That 13-year-old German schoolboy has done a marvellous job because it's
one of those things that perhaps if you look back 100 years, people used
logarithms for this process to work out asteroid orbits and hand-calculators
and slide rules and things like that," he said.

"The process took days and days, but it says a lot for the world that we
live in that now a 13-year-old schoolboy can download the right software to
do the job and actually find out errors in NASA's work. It's quite
extraordinary."

'Great brains'

Professor Watson says it proves even the great brains of NASA can get it
wrong.

"Honestly, it's very hard to overstate just how good NASA is at this kind of
thing, even though they sometimes get their imperial units and their metric
units mixed up," he said.

"But it's very hard to think of everything and that's what has happened in
this case.

"The schoolboy has thought of something that would actually elude most
people, and that's the possibility of the asteroid Apophis when it makes its
close path to the Earth, interacting with one of the Earth's geostationary
satellites.

"These are our communication satellites which exist in many thousands in a
band about 36,000 kilometres above the Earth's surface.

"That is something - once you see that it sticks out as plain as the nose on
your face - but it's one of those things that you really have to think
about."

Professor Watson says he suspects the only thing that would really make any
difference would be a collision, because Apophis weighs infinitely more than
a satellite.

"It's on a trajectory which has a speed rather greater than these
satellites, so a collision could make a microscopic but nevertheless
tangible change to its orbit," he said.

He says with this new calculation of a one in 450 chance of the asteroid
hitting the Earth, the critical time is actually 2036, not 2029.

"2029 is when it makes a close approach and 2036 is when the big uncertainty
is," he said.

"We don't know what the Earth's gravity will do until we pass the asteroid
in 2029, in terms of where it will be a few years later."