EXPLORING HIS VAST CATTLE station in 1899, Walter Parke came upon a feature in the landscape he could not explain. A 15m-deep, bowl-shaped depression, larger than a football field, had been gouged out of the Central Australian desert. “One of the most curious spots I have ever seen in the country,” he wrote in a letter to the anthropologist Frank Gillen. “An immense amphitheatre…To look at it I cannot but think it has been done by human agency, but when or why, goodness knows.”
Further investigation revealed 12 craters pitting Parke’s property at Henbury station, 115km south-west of Alice Springs. But their origin remained a mystery to Europeans until 1931, when local prospector, J. M. Mitchell, reported finding slugs of iron strewn across the site, “as though they had dropped from a molten mass falling at great speed”.
Massive asteroid impact chances “extremely slim”
As one of the oldest and least geologically disturbed continents, Australia has a rich record of meteorite craters. Of 176 confirmed impacts worldwide, our country bears the pockmarks of 30 – and about 20 others await confirmation. Indeed, as you read this, another 1275 potentially hazardous asteroids (meteorite is the name of an asteroid once it has fallen to Earth) are orbiting in space – and that’s just the ones we know about.
“An impact in Australia in the future is certain,” says Duane Hamacher, an astronomer from Macquarie University in Sydney. “The recent flyby of ’2005 YU55′, a 400m asteroid – which passed closer to the Earth than the Moon – posed no threat to us, but had it impacted, it would have created a crater more than 6km wide and could have completely eradicated a large city like Sydney or Melbourne.”
The 2005 YU55 was the largest object on record to pass this close to the Earth with our foreknowledge, but smaller meteors arrive surprisingly frequently.