INCOMING! Asteroid to Narrowly Miss Earth on Monday

Astronomer Mark Thompson reports on the large asteroid that will pass within 8,000 miles from Earth and why we were given such short notice.

This may sound like late notice, but astronomers have just spotted a rather chunky asteroid heading our way, set to narrowly miss us on Monday.

In fact, it will be such a narrow miss that astronomers in the Southern Hemisphere should be able to spot the flyby with fairly modest telescopes.

Coincidentally, I was watching yet another re-run of Armageddon the other night when the heroic Bruce Willis and his motley crew of oil drillers-turned-astronauts saved Earth from certain asteroid doom. On arrival at the asteroid, and having sacrificed many of the team, Willis et al. succeeded in dropping a typical Hollywood-style uber-bomb into the depths of the incoming asteroid and blew it to bits, giving everyone on Earth a glitzy meteor shower.

I'm not so sure it will be really that easy to destroy an incoming asteroid (see my previous Discovery News article "How do we dodge the next incoming asteroid?") particularly given the 12 days notice they had in the film.

Yet we are forced to consider our delicate position when the Lincoln Near Earth Asteroid Research (LINEAR) project discovered an asteroid called 2011 MD. It's heading our way, and we've only been given four days notice.
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Working from their base in New Mexico, the LINEAR team uses automated one-meter ground based telescopes to probe the skies for so-called near-Earth object (NEO) threats. The discovery of 2011 MD on Wednesday goes to show that we need to get better at identifying potential asteroid threats, investing more money and time into projects like LINEAR. The more time we have, the greater chance there is of us being able to do something about it.

Surprisingly, NEOs are more common than you think with around 8,000 known. This newly discovered interplanetary interloper is thought to measure no more than 20 meters wide, making it no real threat -- but it's a warning all the same.

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If 2011 MD did hit us, then it would more than likely break up in the atmosphere and give us an amazing display of fireballs and meteors. As it turns out, it will sail harmlessly by at a butt-clenchingly close distance of only 12,000 kilometers (7,500 miles), 32 times closer than the moon, and closer than some geosynchronous satellites.

It will get so close to the Earth that the asteroid's trajectory will be altered by our planet's gravitational field.

"We are certain that it will miss us, but if it did enter the atmosphere, an asteroid this size would mostly burn up in a brilliant fireball, possibly scattering a few meteorites," UK asteroid expert Emily Baldwin, told Skymania News on Thursday.

The moment of closest approach will occur on Monday, June 27 at 13:30 UTC somewhere over the South Atlantic Ocean. Its visibility will be severely limited, but amateur astronomers in Australia and New Zealand should be able to track 2011 MD in the night sky just before closest approach.

news.discovery.com