A huge asteroid heading for Earth could kill 1.5 billion people and devastate the planet, scientists at an international gathering said Monday in Garden Grove.
The only question is when.
"It could happen this year or in a century or in a millennium" or far longer, said David Morrison, a space expert at NASA Ames Research Center at Moffett Field, in Northern California. Whenever it does, he said, we need to be ready.
Making sure that we are is the mission of 120 scientists and engineers attending the four-day gathering called the Planetary Defense Conference: Protecting Earth From Asteroids, which began Monday at the Hyatt Regency hotel. Billed as the first major conference of its kind, the confab has attracted astronomers, aerospace engineers, astronauts and emergency preparedness specialists from throughout the United States as well as Italy, Great Britain, Canada, the Netherlands, Germany and Russia.
Among the strategies to be discussed are such extravagant-sounding scenarios as deflecting asteroids with nuclear warheads, lasers and mirrors -- which would create gas jets that would disrupt the object's trajectory.
"We have reached a point in the evolution of life on this planet where we can actually do something about this, but not if we don't start planning," said Bill Ailor, director of the Center for Orbital and Reentry Debris Studies at the Aerospace Corp. in El Segundo, which organized the conference along with the American Institute of Aeronautics and Astronautics in Reston, Va. "Our goal," Ailor said, "is to raise the consciousness of the public and of people who work in the field."
Rep. Dana Rohrabacher (R-Huntington Beach) who, among other things, chairs the House subcommittee on space and aeronautics and has introduced two bills encouraging research on threats from outer space, set the tone during a keynote address.
"Bin Laden was out there like a near-Earth object for a long time," he said. "It took 9/11 -- the slaughter of 3,000 innocents -- for us to pay attention to that threat. I hope it won't take that long for us to recognize the threat of near-Earth objects; so far we've had a very tepid response."
In fact, the U.S. government has been tracking and charting the paths of large asteroids since 1998. To date, Morrison said, about 60% of all those known have been charted; about 90% are expected to be done by 2008. "Among those charted," he said, "there appears to be no danger." As for the others, Morrison said, "I can't tell you anything about them -- one could hit us in an hour, though it's not very likely."
He bases that mixed assessment on the belief of most scientists that truly catastrophic asteroid collisions occur only about once every million years. The uncertainty, he said, stems from the fact that, because the last such collision occurred in prerecorded history, its date is unknown. (A more minor incident -- the magnitude of which occurs about once every 100 years -- happened in 1908, leveling more than 1,000 square miles of Siberian forest.)
"We want certainty," Morrison said. "If you cross a street, you don't predict the probability of a car being there; you look to see if one's coming."
Conference organizers say that, for starters, they intend to encourage the continuation of that process. The conference -- held in Garden Grove because, Ailor said, "it seemed like a good place to start [and] the weather is good this time of year" -- is expected to be the first of many held at least once every four years.
At Monday's opening session, participants heard presentations on the threat posed by asteroids and the methods by which it is assessed. Sessions through the rest of the week, Ailor said, will cover such topics as how to move a near-Earth object off course (including the early planning of a mission to do so), how to prepare for the disaster that will ensue if preventive efforts fail, and how to affect political and policy issues related to the impending threat.
"We want people to get excited about this topic," Ailor said. "We want young people to consider it as a subject for future work."