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Here at the Meteoritical Society Meeting in Los Angeles this morning there has been much excitement at the news that asteroid 2002 NT7 may approach close to the Earth in 2019. Scientists involved in asteroid research have a very different view on such objects than most people. When an asteroid comes close to the Earth it gives us an opportunity to study it in more detail using Radar and there are one or two scientists here who expressed the hope that it passes close enough for us to mount a space mission to return a sample to Earth.
Not one of the asteroid scientists present at the conference is worried that 2002 NT7 will collide with the Earth. We all know that with a chance of only 1 in 60,000 of an impact that the asteroid will probably pass us at a very respectable distance and that in all
probability new observations over the next month will show that asteroid 2002 NT7 is no threat at all. The Minor Planet Center, who catalogue all Near Earth Objects, are, for example, currently predicting that the asteroid will pass by at a distance of 14 million
kilometres in 2019 and actually came closer back in 1980. This will disappoint those here who would like to grab a piece as it flies past.
The reason for the uncertainty is not that scientists can't agree on where asteroid 2002 NT7 is going, it's simply that as a newly discovered asteroid we haven't yet been able to observe it for long enough to make an accurate prediction. Tracking asteroids is very much like crossing the road. Catch a glimpse of a car when you look left and right and you can more or less tell where the car is going and how fast. However, before stepping into the road you need
a longer look to tell if it is really safe. Thankfully asteroids, however, unlike cars, never swerve at the last minute.
The reason asteroid 2002 NT7 has scored highly on the Palermo Scale is mainly because of its large size, at 3 to 4 km, and the fact that 2019 is quite soon. On the Torino Scale the asteroid scores 1, less than asteroid 1950 DA which has a 1 in 300 chance of colliding with Earth in 2880.
Dr Steve Ostro, from NASA's Jet Propulsion Laboratory, who talked yesterday about Radar measurments of the shape of asteroid 1998 SF36, the target asteroid of the MUSES-C mission, would like to get asteroid 2002 NT7 in his sights. However, the asteroid will probably be too far away in 2019 to examine in detail with Radar. The overall opinion on asteroid 2002 NT7 was probably best summed up by Dr Tom Burbine, an asteroid expert from the Smithsonian Institution. Tom Burbine told worried students this morning "It's only a one on the Torino Scale," said Burbine ", a one means nothing, it's a ten that means you're dead."
Asteroid 2002 NT7 is, however, important. It's another example to show that occasionally the Earth does get hit by asteroids and comets, and that we should continue to find and track these objects. It's also unlikely to be the last time that a newly discovered asteroid has a chance of colliding with us.
Matthew Genge
at the Meteoritical Society Meeting in Los Angeles
More info: The Meteoritical Society
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