Measuring 45 meters in diameter and weighing an estimated 130,000 metric tons, Asteroid 2012 DA14 is considered small by scientists who track the solar system’s rocky debris, but it will zip past Earth so closely that it will be even nearer than orbiting weather and communications satellites.
It is the closest-ever-predicted approach for an object this size. Experts emphasize there is no reason for concern.
“There’s no danger to the planet at all,” said Lindley Johnson of the National Aeronautics and Space Administration’s Near-Earth Object Observations Program in Washington. “We know the orbit quite well now.”
Johnson said Asteroid 2012 DA14 will come as close as 27,700 kilometers, about one-tenth the distance between the Earth and the Moon and about 17,200 miles.
“Close flybys of asteroids happen quite frequently,” said Johnson, who said more than 20 asteroids have come between the Earth and the Moon in the past year. “But they’re usually very small-sized objects, maybe only a few meters in size.”
The 45-meter asteroid will speed past us at about 7.8 kilometers per second, about 4.8 miles per second and nearly 10 times faster than a speeding bullet.
It will be closest to Earth Friday at approximately 19:24 UTC or 1:24 p.m. Costa Rican time. NASA says at that time the asteroid will be visible in parts of Eastern Europe, North Africa, Asia and Australia. Skywatchers will need binoculars or a telescope to glimpse the faint, quickly moving point of light.
Astronomers in Spain first observed 2012 DA14 last February. Johnson said it is not surprising that the asteroid was not detected until recently.
“The orbit last year brought it close enough so that it would be within the detection limits of the observatories that we have doing this survey,” Johnson explained.
NASA estimates that about 100,000 objects this size are in Earth’s vicinity. On average, one gets close every 40 years and hits every 1,200 years.
In 1908, a slightly smaller asteroid exploded over Tunguska, Siberia, leveling trees over 2,000 square kilometers, about 770 square miles.
The flyby is a remarkable opportunity for scientists.
“It provides us the next best thing to doing a spacecraft flyby of an asteroid,” said NASA’s Johnson. “It’s kind of nice that nature gives us these natural opportunities to examine these objects and learn all we can about them.”
NASA has plans to launch a spacecraft in 2016 to study another asteroid and retrieve a sample for study here on Earth.
As for Asteroid 2012 DA14, NASA says that its next notable close approach to our planet will be in 2046.