Stranger in the night: space rock to make close Earth flyby

A little-known asteroid will skim past Earth on 15 February, passing just 28 000 km from our planet. The 50 m-diameter chunk of space rock was discovered in last year by ESA-sponsored amateur astronomers in Spain.

Details of the ancient asteroid, 2012 DA14, are sketchy – no direct measurements of its size are available. From its brightness, scientists estimate its diameter at 50-80 m. Its composition is unknown and its mass is thought to be of the order of 130 000 tonnes.

What is known is that it will not impact Earth anytime soon.

“Its orbit can be computed quite accurately using Europe’s NEODyS asteroid database,” says Detlef Koschny, responsible for near-Earth objects at ESA’s Space Situational Awareness office.

“These computations show that a collision with Earth can be excluded quite safely at least for this century.”

On 15 February, the asteroid will make its closest pass to our planet this century when it flies by at 7.8 km/s at a distance of just within 28 000 km.

“This is well inside the geostationary ring, where many communication satellites are located,” says Detlef. “There is no danger to these satellites, however, as the asteroid will come ‘from below’ and not intersect the geostationary belt.”

The asteroid will make its closest approach at around 19:40 GMT (20:40 CET) on Friday evening next week. While tiny against the vastness of our Solar System, it should be visible in Europe to anyone with a good pair of binoculars and an idea of where to look (see link to details below).

Amateur discovery

The asteroid was discovered by the La Sagra Sky Survey, which is supported by ESA’s Space Situational Awareness programme, on 22 February 2012. The observatory is in southeast Spain, near Granada, at an altitude of 1700 m, one of the darkest, least light-polluted locations on the European mainland.

The small size and previously unknown orbit of 2012 DA14 meant that it was spotted only after it had flown past Earth at about seven times the distance of the Moon.

“If this object were made of iron and it were to hit our planet, it could create a crater comparable to the 1.5 km Meteor Crater near Flagstaff, Arizona, for example,” says Detlef. “However, it won’t.”