Astronomical Visitors – Hello 2012 DA14

Next Friday a 46m (151 feet) diameter asteroid is going to be making a fly-by of Earth. The microscopic aliens who inhabit the little world, roughly the mass of an aircraft carrier, have prepared their miniature cameras to get nice snaps of the weird ‘big people’ below as we go about our daily lives. We’ll be watching too.

The asteroid, poetically dubbed 2012 DA14 in accordance with the naming convention, will pass within 27,680 km (17,200 mi) of Earth. Geosynchronous orbit is at 36,000km, so this visitor will actually pass between the orbit of various GPS and TV satellites and Earth. NASA scientists assure there is no chance of collision.

It will zip past at around 27,000 km/h (17,500 mph), and should be visible through binoculars and telescopes.

The best viewing location will be Indonesia, but Australian watchers should get a pretty good view as well. It will be visible from around 0624 Australian Eastern Daylight Time (i.e. Sydney, Melbourne, Canberra etc) on February 16 – that 524am for us Brisbanites (that’s our Saturday morning). The asteroid should be visible as a small star moving against the background of stars.

A telescope at NASA’s Marshall Space Flight Center in Huntsville will broadcast its view of the event from 6pm to 9pm USA ET on February 15.

Conventional wisdom says that asteroids of around 50m in diameter pass by Earth every 40 years or so, but are only expected to impact the Earth around every 1200 years.

The asteroid is thought to be similar in size to the object that exploded over Tunguska, Siberia, in 1908. The shockwave levelled hundreds of square kilometres of forest. Whether an asteroid makes impact or detonates in mid-air is down to its composition. The Tunguska explosion was thought to result from a rocky asteroid, as opposed to more metallic asteroids that have more structural integrity and stay intact up to impact.

This is the closest approach on record to Earth for an asteroid of its size.

Observations from the fly-by will hopefully gives clues on the asteroid’s composition and structure.

Any plans to watch the asteroid fly past?

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