A high-rise-sized asteroid slipped quietly past the Earth yesterday, twice as close as the moon. We didn’t see it coming.
Now designated as 2017 AG13, the 10-storey (80-115 feet) tall space rock was first spotted late on Sunday by the Catalina Sky Survey. It was traveling at roughly 35,000 miles per hour.
“This is moving very quickly, very nearby to us,” an expert with astronomy news website Slooh, Eric Feldman, said during a hastily arranged live broadcast of the fly-by yesterday.
He said the asteroid was roughly the same size as the one that exploded in the sky above Chelyabinsk, Russia, in 2013. The Chelyabinsk blast shattered windows and caused minor damage to buildings over a wide area. More than a thousand people were reportedly injured by flying glass and debris.
2017 AG13’s orbit will also take it through the path of Venus, he said.
The asteroid was roughly half the size designed to be detected by NEOCam, an infra-red telescope surveying the sky for potentially damaging asteroids that have orbits intersecting with Earth’s.
The program last week received only partial funding from NASA to continue its search.
Planetary defense
Last month, the White House released a document outlining a Near-Earth Object Preparedness Strategy.
The policy document seeks to “improve our nation’s preparedness to address the hazard of near-Earth object (NEO) impacts by enhancing the integration of existing national and international assets and adding important capabilities that are currently lacking.”
In the case of 2017 AG13, the asteroid would likely have exploded high in the atmosphere with the force of 700 kilotons. The Nagasaki atomic bomb was 20 kilotons.
Early warning remains an issue, the document admits.
Asteroids vary in size, brightness, and orbit — making many of them difficult to identify and track.
They can range from a few feet to several miles across. Some are made of ice. Others rubble. Some can be almost pure metal.
The Planetary Society believes only 60 percent of near-Earth objects bigger than 1 mile wide have so far been spotted. The number of smaller objects is many times this.
But the chances of a “potentially hazardous” asteroid impact on Earth in the next 100 years is just 0.01 percent, the White House document says.
Roughly five new asteroids are being discovered every day.