"Until now, scientists thought the population of large, near-Earth asteroids was between 1,000 and 2,000, but we've downgraded that figure significantly," said Dr. David Rabinowitz, of Yale University, New Haven, CT, lead author of the article and NEAT co-investigator. "We now believe there are between 500 and 1,000 near-Earth asteroids larger than one kilometer (about 0.6 miles) in diameter."