News in Science

More education needed on asteroid threats

A report being presented this week to the United Nations suggests politicians, emergency services and the public need to be better educated about the threats posed to Earth by asteroids.

The Near Earth Object Media/Risk Communications Working Group report says governments don't understand the threats or responses needed to deal with an impact event.

The report by Secure World Foundation, a scientific think tank, says an effective international communications and educational strategy needs to be developed explaining how an impact risk assessment is formulated.

The authors say there is also a need to communicate the uncertainty associated with such forecasts and explain them in non-scientific terms that reduce the risk of misinterpretation.

Impactor threats

They found the most immediate threats are not huge extinction level event asteroids, which are several kilometres across, but smaller impactors capable of destroying a city or triggering a tsunami.

The report gives the example of the 1908 Tunguska impact event in Siberia which flattened 80 million trees over an area of 2200 square kilometres. It is thought to have been caused by an asteroid only about 40 metres wide.

According to the report, these smaller near Earth objects, or NEOs, are likely to escape detection.

"Any advance warning might be on the scale of hours, and the response might require an evacuation similar to New Orleans as hurricane Katrina approached," the report says.

However the report warns there's no worldwide disaster-notification protocol, the closest analogy being the early warning system developed after the 2004 Indian Ocean tsunami.

It says recent uncontrolled re-entries by NASA's Upper Atmosphere Research Satellite, Germany's ROSAT spacecraft, and Russia's failed Phobos-Grunt mission, triggered widespread interest and concern.

Despite assurances that there was little risk of harm, the report found these events generated alarmist articles apparently deliberately designed to frighten.

Australian support

Professor Harvey Butcher, Director of the Australian National University's Mount Stromlo Observatory supports the studies recommendations.

"The report's right on the mark," he says.

Butcher says more effort is needed to determine the orbits of potentially hazardous asteroids.

"If something's going to hit, we need to know very accurately where," he says.

According to Butcher, "there's been a decade long space watch program in Australia, funded by NASA, which was very successful in searching for asteroids threaten the planet. But that's now finished."

He says the amount of money needed for such a program is relatively low.

"All you need is an astronomer with a telescope."