David Chandler in the Boston Sunday Globe Magazine, December 13, 1992:

The scientists [astronomers James Scotti and Tom Gehrels] have been developing and testing computer software and designing and improving their equipment since 1981, and the full-scale search for asteroids began in earnest two years ago. This past March, a committee appointed by the National Aeronautics and Space Administration issued a report recommending that the United States commit itself to a $50 million project to build a network of six telescopes. Modeled on the Spacewatch project, it would be asked to do a thorough search to find out if there is an asteroid out there with our name on it, and if so, when it is due.

The committee estimated that an object big enough to cause global effects, casting a pall of dust over the planet that could destroy a year or more of agricultural production and causing mass starvation on a truly apocalyptic scale, may strike Earth about twice every million years. It probably has not happened since humans have existed. The odds of its happening in one person's lifetime are about one in 70,000—comparable to the risk of a person's dying in a plane crash, says David Morrison, chairman of the committee and an astronomer at NASA's Ames Research Center, in Mountain View, California. The odds of its happening during a congressional term of office, perhaps the most relevant statistic in seeking support for the proposal, is a figure that does not appear in the report.

Astronomers see the search for Earth-crossing asteroids as a means of gaining a fundamental knowledge about the solar system, and about our prospects, a knowledge that humanity simply ought to have available. Scientists involved in the Strategic Defense Initiative, the so-called Star Wars project, see the search as a way of preparing for a threat that they might be able to do something about, providing them a raison d'etre now that the Cold War is over. Jim Scotti sees it as a wonderful way to make a living.

"It's like insurance," says astronomer Richard Binzel, a committee member from the Massachusetts Institute of Technology. "The key is that we have the technology to detect these objects. We are now able to protect ourselves in a way that the dinosaurs weren't."

Binzel says the group members "tried to be very conservative" in figuring the odds, and they decided not to include the comparison with plane-crash statistics in the report because even though the numbers are correct it might mislead the public. People die in plane crashes every year, after all, and no human has ever been killed, so far as we know, by a meteorite—the generic term for any object that enters Earth's atmosphere and makes it all the way to the surface.

The only documented case of a human being struck by a meteorite took place in Alabama in 1954, when a woman was hit on the hip by a fist-sized rock that came through the roof of her home. She sued her landlord for negligence, but the court found in his favor.

†