If end is near, do you want to know?
By Richard Stenger
(CNN) -- If scientists detect a killer asteroid shortly before it slams into Earth, should the public be informed?
One researcher, Geoffrey Sommer of the Rand Corp., a Santa Monica, California-based think tank, believes the best answer in some cases is no.
Should an alert come too late to make a difference in the outcome of a global catastrophe, Sommer suggests governments should remain silent.
"If you can't do anything about a warning, then there is no point in issuing a warning at all," Sommer said earlier this month at an American Association for the Advancement of Science meeting in Denver.
"If an extinction-type impact is inevitable, then ignorance for the populace is bliss," he said.
Other space researchers were highly critical of Sommer's views.
"I find Geoffrey's whole idea both irrational and unrealistic," said Benny Peiser, a U.K. scientist at Liverpool John Moores University who monitors asteroid threats.
"The advocated secrecy, far from being cost-effective as Geoffrey claims, would most certainly preclude any attempt at impact mitigation," he told CNN.com.
Regardless, Peiser said, any attempt to keep a killer asteroid quiet would be futile.
"Professional and amateur astronomers from around the world can easily access and confirm observational data and calculations of any discovered NEOs [Near Earth Objects]," he said.
Scientists estimate more than 1,000 asteroids 1 kilometer (0.6 miles) in diameter or larger -- big enough to cause global devastation -- lurk near the Earth's orbital path.
NASA expects to finish a census of the so-called NEOs in 2008 and has already identified more than half of the predicted population.
One particularly sizable space boulder is thought to have unleashed global climate changes that hastened the end of the dinosaurs 65 million years ago.
Yet collisions with such monster rocks are rare. They take place about only once every 1 million years or so.
Smaller asteroids the size of whales collide every few centuries. Most plunk in oceans, but they could spark regional disasters if they were to hit near a populated area, according to astronomers.