Cosmic hole-in-one captured over Antarctica

Aug 25, 2005
Artist's impression of the view of the meteoroid fireball near the explosion site.

What at first looked like an electronic glitch turned out to be a significant event in space, in fact, a cosmic hole-in-one.
What a powerful telescope had picked up as it stretched towards the night sky over Antarctica was the trail of dust left in the wake of the death of an asteroid.
The remarkable story features in the latest edition of the prestigious international science journal, Nature.

Image: Artist's impression of the view of the meteoroid fireball near the explosion site. (A. Klekociuk & D. Ratcliffe)

Lead author, Dr Andrew Klekociuk, from the Australian Antarctic Division said that early last September, a physicist at Australia's Davis station in Antarctica had prepared his monitoring instrument, known as LIDAR, for keeping watch on atmospheric activity during the long night ahead.

"Just as observation of the stratosphere began a strange signal was recorded from 30 kms overhead. Our physicist thought his preparation of the optics may have been amiss so fitted a filter but the signal persisted for another 30 minutes.

"What he didn't know at the time was that seven hours earlier an asteroid had crashed to Earth in another part of Antarctica, about 1500 kms west of Davis. The closest it got to human habitation was around 900 kms west of Japan's Syowa station," Dr Klekociuk said.

Shortly after the LIDAR observations it was revealed that the event had also been picked up by the global network of satellites and a range of other instruments.

But the most detailed evidence of the trail of dust, carried by strong winds around Antarctica, has been captured by the LIDAR at Davis station.

Dr Klekociuk said that it was thought that the asteroid had come from what is known as the Aten group somewhere between Venus and Earth, ranging anywhere up to 46 million kms from the sun. Measuring roughly 10 metres it is the biggest body to enter Earth's atmosphere in the past decade.

Its travel time from entering Earth's atmosphere 75 kms up until it landed? Just five seconds.

Laser scatter caused by the dust cloud, 28-31 km up, over about one hour.
Laser scatter caused by the dust cloud, 28-31 km up, over about one hour. Photo: A. Klekociuk

Scientists believe that the asteroid's original size was close to that of a small house weighing a thousand tonnes and that if it had not broken up on entry into the atmosphere its effect on impact would have been that of the bomb dropped on Hiroshima.

"The size of the dust cloud in the stratosphere was 200 kms by 75 kms. Had a cloud that size passed over the sun the light would have dimmed by around 20 per cent.

"Inevitably particles contained in the dust cloud have fallen to Earth and samples from all three Australian Antarctic continental stations - Davis, Casey and Mawson - have been retrieved for analysis at the Australian Antarctic Division."

Dr Klekociuk said that these analyses will enable scientists to validate models of atmospheric circulation. The timing and location of the event will also allow for testing theories relating to the impact of large meteorites on ozone and climate.

"While there were no obvious short-term associated changes in regional climate or ozone levels, the longer term implications are still being evaluated," Dr Klekociuk said.

Importantly, this event occurred just inside the Antarctic stratospheric vortex - a region of air that forms over the continent each winter and which is effectively isolated from air at lower latitudes. This means that the dust was confined to the Antarctic region for several weeks, giving the particles time to fall to the surface and be incorporated in the ice record. These and future samples will be important for confirming the meteor's composition and determining other properties.

Source: Australian Antarctic Division

Explore further: Mysteries of space dust revealed

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Mysteries of space dust revealed

Aug 29, 2014

The first analysis of space dust collected by a special collector onboard NASA's Stardust mission and sent back to Earth for study in 2006 suggests the tiny specks open a door to studying the origins of the ...

A guide to the 2014 Neptune opposition season

Aug 29, 2014

Never seen Neptune? Now is a good time to try, as the outermost ice giant world reaches opposition this weekend at 14:00 Universal Time (UT) or 10:00 AM EDT on Friday, August 29th. This means that the distant ...

How can we find tiny particles in exoplanet atmospheres?

Aug 29, 2014

It may seem like magic, but astronomers have worked out a scheme that will allow them to detect and measure particles ten times smaller than the width of a human hair, even at many light-years distance.  ...

Spitzer telescope witnesses asteroid smashup

Aug 28, 2014

( —NASA's Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the ...

User comments : 0