Little Meteor Leaves Big Hole

On 15 September 2007, villagers from the Peruvian settlements of Desaguadero and Carancas saw a light as bright as the sun streak across the sky, heard what sounded like an explosion and felt the earth shake beneath them. After further investigation, they found a gaping hole, thirteen metres wide and two meters deep, full of boiling water, in the soil.

In December, scientist from around the world, including Peter Schultz, a leading specialist in extraterrestrial impacts from Brown University, collected samples of the shattered meteorite that caused the crater. It was identified as an ordinary chondritic meteorite, 0.5 to 2 metres across, based on the crater’s size. Conventional impact theories say that the meteor could not have been large enough to survive the passage through the atmosphere. It would have broken up into fragments as it entered the atmosphere, leaving widely strewn pieces, none big enough to leave a crater. However, Schultz and his team concluded that the size and composition of the meteorite meant that established impact models were not appropriate.

Schultz believes that the meteor may have reshaped itself into a form that reduced atmospheric drag, thus allowing it to survive the passage through the atmosphere. According to Clark Chapman, a specialist in asteroid and comet impacts at the Southwest Research Institute in Boulder, Colorado, this could change the way we deal with potential asteroid impacts. Previously, it was thought that anything smaller than 50 metres across is harmless, but now it seems that a meteor 20 metres across, which has an average probability of arriving once every century, could also pose a great danger.

Schultz’s team have been interviewing witnesses of the strike, hoping to find more clues about such things as the angle and direction of entry, and the region of space the meteor came from. It is hoped that the findings will enable scientists to better estimate which objects will pass through the atmosphere.