When Congress asked the U.S. space agency NASA how the world can be protected from marauding asteroids and careening comets, the officials at NASA gave a collective shrug and space agency chief Charles Bolden simply responded: "Pray."
That's the unsettling news that came from Washington D.C. just weeks after a large meteor exploded over northern Russia with the force of many Hiroshima-sized atomic bombs. The atmospheric detonation of the meteor caused extensive damage to a city and caused some injuries, although none were life threatening.
NEOs (near Earth objects) are tracked and their orbits constantly being monitored, but Bolden told apprehensive Congressmen that so many unknown objects orbiting the sun and zipping though the solar system there's no way to account for or predict many of them. On any given day a city-killer sized asteroid (about 165 feet in diameter) could suddenly appear and arc into a fiery plunge toward Earth taking out New York City, London, or Moscow.
The Russians, well aware of that, have taken a much more aggressive stand in dealing with potential city, continent, or world-killing asteroids and comets. They've embarked on a program to fend of potential Earth threatening NEOs and have sought the assistance of the ESA (European Space Agency).
NASA is currently tracking about 95 percent of asteroids and comets that have the potential to wipe out most life on Earth. Any space rock bigger than about a half-mile wide could do the job. Unfortunately the city-killers are much greater in number and of the estimated 10,000 whirling about the solar system only about 10 percent have been identified by NASA.
While it's been thought for some time that a six-mile wide asteroid did in the dinosaurs some 65 million years ago after the Chicxulub impact in the Yucatan, recently new research has revealed that the deadly visitor may actually have been a comet.
Statistically a city-killer size asteroid smacks into Earth about every 1,000 years. But those are statistics and nothing says that two or three couldn't arrive within weeks or months of each other. While astronomy is one of the oldest sciences, there is still a very great deal that's unknown, even in our planet's back yard.
Speaking about the odds of an unknown asteroid taking out an American city, Bolden admitted, "From the information we have, we don't know of an asteroid that will threaten the population of the United States. But if it's coming in three weeks, pray."
The admission disturbed many of the politicians at the meeting, and though the risk on any given day is small the eventuality of a strike looms larger each passing year.
"The odds of a near-Earth object strike causing massive casualties and destruction of infrastructure are very small, but the potential consequences of such an event are so large it makes sense to takes the risk seriously," Bolden told the committee.