The asteroids closest approach will now be at 1:14 p.m. EDT or 17:14 GMT on June 27, 2011 and will pass just over 7,500 miles (12,000 kilometers) above the Earth’s surface, NASA officials stated. At that particular moment, the asteroid, which scientists have named 2011 MD, will be sailing over the coast of Antarctica, almost 2,000 miles, or 3,218 km south-southwest of South Africa.
Asteroid 2011 MD was discovered on Wednesday, June 22, 2011 by LINEAR, which are a pair of robotic telescopes in New Mexico that scan the heavens currently for near-Earth asteroids. The best current estimates suggest that this asteroid is between 29 to 98 feet (9 to 30 meters) wide.
According to NASA’s Near-Earth Object Office at the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., an object of the size of Asteroid 2011 MD can be expected to come this close to Earth around every 6 years or so, on average. “There is no chance that 2011 MD will hit Earth but scientists will use the close pass as opportunity to study it w/ radar observations,” astronomers with NASA’s Asteroid Watch program at JPL wrote in a Twitter post on Thursday June 23, 2011. Even if the asteroid were to enter Earth’s atmosphere, it likely wouldn’t reach the surface due to it’s small size, they added. They stated that “Asteroid 2011 MD measures about 10 meters. Stony asteroids less than 25 m would break up in Earth’s atmosphere & not cause ground damage,” scientists said.
Asteroid MD 2011’s near Earth encounter will be a close call, but will not set a record for the nearest of nearby passing asteroids. The record for nearby passing asteroids currently is held by the asteroid 2011 CQ1, which came within 3,400 miles (5,471 kilometers) of Earth on Feb. 4, 2011, which was earlier this year.
Asteroid MD 2011 poses as a tricky sky watching target, as for several hours prior to its closest approach, 2011 MD will be visible in moderately-large amateur telescopes. But despite its close approach, actually seeing this asteroid will be no easy task. “These objects are so small (10 meters) that normally a sizable telescope is required,” Asteroid Watch scientists proclaimed.
To view the MD 2011, you will need to have access to an excellent star atlas, and because it will be moving so rapidly you’ll also need the very latest data from the Minor Planet Center to track its precise course against the background stars. The asteroid is not expected to get very bright, only about 250 times dimmer than the faintest stars visible to the eye without any optical aids.
One thing is certain though, the asteroid will be passing so close to Earth that the Earth’s gravity will sharply alter the asteroid’s current trajectory. After making its closest pass to Earth, the asteroid will zoom through the zone of geosynchronous satellites. Experts say that the chance of a collision with a satellite or piece of space junk will be exceedingly remote.
Brief History of near-Earth asteroids
On Oct. 28, 1937, German astronomer Karl Reinmuth (1892-1979) accidentally photographed the long trail of a fast moving asteroid. Two nights later, this asteroid passed within 460,000 miles of the Earth. Reinmuth named it Hermes, after the Olympian god of boundaries and travelers.
Since the vast majority of asteroids (so far numbering over 210,000) congregate between the orbits of Mars and Jupiter, astronomers at that time felt that Hermes’ very close approach was an outstanding exception to the rule. “Astronomers of the day were somewhat biased, they had convinced themselves that collisions were too rare to consider.” explained NASA asteroid scientist Paul Chodas.
Since then, astronomers have learned that asteroids can make very close approaches to Earth with far greater frequency than previously thought. Asteroid 2011 MD’s flyby on Monday is a prime example of asteroids making close approaches to Earth.
Currently, of the 8,100 Near-Earth objects that have previously been discovered, only about 827 of them are asteroids with a diameter larger than approximately a half-mile (1 km). About 1,236 of these NEOs have been classified as Potentially Hazardous Asteroids (PHAs), which could result in massive damages to the planet if they were to strike us. NASA currently plans to launch a probe to visit one of these potentially dangerous near-Earth objects and return samples of the asteroid to Earth for analysis.
That mission will launch the OSIRIS-Rex asteroid probe in 2016 to rendezvous with the space rock 1999 RQ36 in 2020. The target asteroid is 1,900 feet (580 meters) wide and has a 1-in-1,800 chance of hitting Earth in the year 2170, and a 1-in-1,000 chance of slamming into us in the year 2182.
So when the clock strikes 1:14 EDT or 17:14 GMT on Monday, June 27, 2011, point your telescopes to the south to view the Asteroid 2011 MD, and enjoy the show!