Rogue asteroid warning
NEWS.COM.AU
July 25, 2002
A NEWLY discovered asteroid could be the most menacing piece of space rock ever
discovered.
Scientists have calculated there is a risk of asteroid 2002 NT7 hitting earth on February
1, 2019.
If it hit earth, the asteroid would be travelling at 28km a second, enough to wipe out a
continent and cause global climatic change.
But astronomers believe observations in the next few days will show it is not on the same
trajectory as earth.
Astronomers have taken the unprecedented step of announcing publicly that NT7 has a
positive rating on the Palermo technical scale of threat.
NT7, 2km wide, was first observed by the Linear search program in New Mexico on July 9.
NT7 has been given a Palermo scale value of 0.38. The Palermo scale compares the
likelihood of the potential impact with the risk of objects the same size or larger
hitting earth. Astronomers have calculated possible impacts on February 1 in 2019, 2035
and 2051.
Since the discovery this month there have been 102 observations of the bright asteroid at
observatories around the world, including Siding Spring in New South Wales.
"The error in our knowledge of where NT7 will be on February 1, 2019 is large --
several tens of millions of kilometres," said Dr Donald Yeomans of NASA's Jet
Propulsion Laboratory.
Astronomers are keen to emphasise that the chance of collision is extremely unlikely.
Last month asteroid 2002MN whizzed between earth and the moon at 36,000km/h and was not
discovered until three days later.
Brisbane scientists have reported in the latest edition of Nature that they have found the
first evidence that earth was pelted by meteorites about 4000 million years ago.
Discovery of traces of a tungsten isotope in rocks found in Greenland and Canada suggest a
hit during a massive meteor storm 3800 to 4000 million years ago.
END OF
REPORT
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