Scan For Science, Not Fiction

Sydney Morning Herald

Saturday April 5, 2008

Anne Fawcett

Someone is out there to help save the planet, writes Anne Fawcett.

Gordon Garradd reckons he has an ordinary desk job but he and his colleagues may just hold the key to saving the planet.

There are millions of asteroids in the solar system, with many orbiting close to our planet. According to the experts, it's inevitable that at least one is on a collision course with Earth.

Garradd, one of only two scientists in Australia dedicated exclusively to watching the skies for incoming asteroids or comets, says that an object a kilometre in diameter would carve a crater 10 to 20 kilometres across. But the damage wouldn't stop there.

"It would throw up rock which would be vaporised in the air, re-condense and fall out of the sky as red-hot rock rain, setting everything on fire," he says. "Giant tsunamis would hit the ocean. There's a lot more energy in an asteroid of that size than there is a nuclear bomb."

Those living within a few hundred kilometres of the impact would perish. Dust and smoke from the event would blot out the sun in some areas, causing crops to fail. The world economy would be plunged into chaos. The probability of such an asteroid colliding with the Earth in the near future is extremely low but the devastating consequences are enough to justify an early warning system. That's where Garradd comes in.

A near earth object (NEO) observer employed by the Australian National University and NASA, he scans the night sky for asteroids of the global-catastrophe-generating size. There is no way to tell at first sight if an asteroid will hit the earth. It must be observed over weeks or months to determine its orbit.

Garradd says his role is not nearly as exciting as it is portrayed in the movies. "It's pretty much a desk job. Asteroids all follow the laws of gravity. You don't just look up and see that one is about to hit. We're much more likely to have five to 50 years' warning about an impact."

In other words, Garradd doesn't have any trouble sleeping at night - or during the day.

Garradd shares his duties with fellow NEO observer Robert McNaught at Siding Spring Observatory in the Warrumbungle Mountains in central-west NSW. They work six nights in a row, followed by six nights off. Each work night Garradd takes between 600 and 1000 photos of the night sky through a telescope, scanning them carefully to discern asteroids from background noise. "In this job you need to be able to pick out moving objects from stars. It can be difficult. Your eyes get fairly tired at the end of the night, you're looking at a computer screen most of the time."

Garradd uses software to keep track of the areas he has surveyed.

Garradd failed to complete degrees in science and business, instead focusing on his interests in amateur astronomy and freelance photography. When NASA provided funding to staff a Southern Hemisphere station at Siding Spring, Garradd was headhunted for the job.

"The best part of this work is the excitement of finding new and interesting objects that have never been seen before," he says. "Between Robert and myself we probably find a new asteroid or comet about once a week."

But he's not holding out for a UFO. "I believe people do see things they can't identify but I don't believe there are alien spaceships buzzing around."

Dr John O'Byrne, secretary of the Astronomical Society of Australia, says jobs like Garradd's are rare. "Most astronomers work in universities where they do a lot of teaching," he says.

O'Byrne says that there are about 200 astronomers working in the country. The conventional path to a career in astronomy is via a science degree with honours, followed by a PhD. "Most of the work is done using computer analysis so computer skills are very important."

Few astronomers have the luxury of gazing at the stars for months on end. "Typically astronomers in research will travel to an observatory for a few nights, make observations, then sit for months analysing data, figuring out what the hell it is they've got."

Nick Lomb, the curator of astronomy at Sydney Observatory, says governments should fund positions for additional NEO observers. "It is serious and important astronomical work and it's sad that there is so little being done in the Southern Hemisphere," he says.

© 2008 Sydney Morning Herald

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