The risk of being hit by an asteroid is 10 times less than it was, thanks to a NASA initiative that has increased researchers’ knowledge about these flying rocks in space.
While our planet absorbs asteroid impacts like a truck grille eats bugs, NASA’s Dr. Donald K. Yeomans has said that most of them aren’t worth getting bent out of shape over.
“On a daily basis, we’re hit with basketball-sized objects, and Volkswagen-sized objects come in a few times a year. Fortunately, the limiting size for something that will actually do ground damage is about 30 meters [98 feet], and you’d expect something like that to come in every 200 years or so on average,” Discovery News quoted Dr. Yeomans as saying.
Dr. Yeomans heads NASA’s Near Earth Object (NEO) Program Office, which continues to spearhead the global effort to identify and track significantly large asteroids in near-Earth space. That directive includes rocks more than a kilometer (0.6 miles) across, which typically hit the Earth in million-year intervals. These asteroids are capable of causing global consequences. Larger objects, including the ten kilometre “dinosaur killer” that occurred 65 million years ago, are capable of plunging the globe into apocalyptic winters that last for years. But luckily, these large object impacts are even less frequent, hitting Earth at intervals in the tens of millions of years.
“Asteroid size has this interesting distribution where there are very few of the big ones. The smaller the size, the more there are,” said Lowell Observatory research scientist Bruce Koehn. “We’ve discovered almost 90 percent of the total population of NEOs larger than a kilometer, and none of them are a threat. So the next step is to extend the survey down to 140 meters [459 feet], which Congress has asked NASA to handle. That will take larger, wider field telescopes, which hopefully will come on line within a few years. Actually one of them is already on line, the Pan-STARRS telescope on Maui,” said Dr. Yeomans. It’s a situation where knowledge is power, and just knowing where the asteroids are has decreased Earths’ estimated risk factor tremendously. “When our project started in the late ‘90s, the risk of dying from an asteroid impact was approximately the same as dying from an airplane crash. Twelve years of near-Earth asteroid surveys have reduced the risk simply by increasing our knowledge. So the risk of being hit by something we haven’t found is 10 times less than it was,” said Dr. Koehn. While it is certain that an asteroid will hit the Earth, the risk of catastrophic impact continues to grow ever fainter.
Still, Dr. Yeomans admits that the NEO search will likely continue for the foreseeable future.