Four asteroids came uncomfortably close to Earth Tuesday, according to NASA’s Asteroid and Comet Watch.
Three of the asteroids won’t get within a million miles of the Earth and will be outside the orbit of the Moon and thus comparatively safe. The smallest asteroid will pass within 197,000 miles of Earth, which is far too close for comfort.
The largest of the four asteroids is 100 feet across, approximately the size of an airliner. This makes it larger than the 65 feet in diameter object that broke up in the atmosphere over Russia three years ago and damaged thousands of buildings. If it impacted Earth and made it through the atmosphere, it could produce an air burst with about twice the energy of the Russian event, and would be capable of destroying a major city.
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When NASA director Charles Bolden was asked in 2013 what the space agency could do if a similar asteroid was on a collusion course for a major city, he simply replied “Pray.”
A different asteroid came disturbingly close to Earth in March, and was 16 times closer to Earth than the Moon. It actually passed closer to the world than many communications satellites. Though Earth is safe for now, NASA’s Center for Near-Earth Object Studies identifies a 1-in-250-million chance the asteroid could impact Earth on Sept. 28, 2017.
In January, NASA created the anti-asteroid Planetary Defense Coordination Office to defend Earth from impacts that could potentially end humanity.
The new office will aggregate previously American asteroid detection programs such as the Near Earth Asteroid Tracking, the Lowell Observatory Near-Earth Object Search, and the Panoramic Survey Telescope and Rapid Response System. The office will also work with international partners such as the Italian Campo Imperatore Near-Earth Object Survey and the Japanese Spaceguard Association.
Globally, asteroid detection programs have found more than 13,500 near-Earth objects of all sizes — 1,218 near-Earth objects have already been found this year, according to the Minor Planets Center. Roughly 1,500 new asteroids that could potentially impact Earth are found every year.
NASA estimates that more than 90 percent of “world-killer” asteroids, which have diameters of more than 3,000 feet, have already been discovered. The agency is now focused on finding objects that are 450 feet in diameter or larger, which could devastate a city or country if they struck Earth.
In the event an asteroid couldn’t be prevented from hitting Earth, the Planetary Defense Coordination Office would work with Federal Emergency Management Agency (FEMA), the Department of Defense, and other federal agencies to coordinate disaster response.
The federal “omnibus” budget approved last month includes $50 million for near-earth object observations and planetary defense, up from just $4 million in 2010.