When an undetected asteroid exploded over the town of Chelyabinsk in Russia on February 15 of this year, it awakened the world’s astronomers to the threat posed by such relatively small and unseen space rocks. Now, a new study led by Peter Brown of the University of Western Ontario has determined that relatively small near-Earth objects careen into Earth’s atmosphere with alarming frequency. The team examined 20 years of data accrued by sensors used by United States government and infrasound sensors stationed around the world. The detectors were originally installed to detect nuclear weapon launches, but they also register the shockwaves produced by asteroids. Brown and colleagues discovered that, during the 20-year period, about 60 asteroids up to 20 meters in diameter had plummeted into the atmosphere. Most exploded over the oceans or remote areas on land. In any case, this is a much higher number than was recorded by telescopes, indicating that the danger of small asteroids has been underestimated and is 2 to 10 times higher than previously thought. More at The Space Reporter.
The auction has been closed.