“More data on asteroid”
Rutland Herald, Rutland, Vermont
January 11, 2006
With reference to Kendall Wild's Jan. 4 story "Doom from the Sky," I thought it important to correct a couple of understandable but significant errors.
Kendall stated correctly that the NEO "community" of astronomers and others saw a possibility of an asteroid (then 2004MN4, recently named Apophis) hitting Earth in 2029, but then goes on to say that after "some more fine-tuning of their computer data," they decided it wouldn't hit in 2029. This is a common misconception that needs to be corrected and better understood by the public. What changed the astronomers' minds was not fine-tuning existing data (implying that they didn't do a good job the first time) but rather additional (i.e., new) telescopic data. As you get more data the uncertainty in the orbit determination gets smaller and smaller. They didn't make errors. They continued (and still continue) to get more data.
He subsequently states that "in 2029 the asteroid will be closer to the earth than the moon is." True, but far more accurate and impressive is the fact that it will pass less than one-tenth the distance to the Moon — in fact closer to Earth than our communication satellites in geostationary orbit.
Overall, however, it is an excellent article on a subject of far greater importance than most people realize. Unreported (since it was not part of the conference on which Kendall reported) we can prevent impacts by near-Earth asteroids (see the Gravity Tractor, Nature, Nov. 7, 2005), and this capability should be demonstrated before we need to use it. The real question is, will we?
Rusty Schweickart
(Chairman, B612 Foundation)
Tiburon, Calif.
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