By HENRY FOUNTAIN
Published: March 20, 2013
Making a case for the need to detect asteroids before they hit Earth, a former astronaut said Wednesday that the number of casualties would have been enormous had the space rock that exploded in Russia last month blown apart directly over New York City instead.
Reuters
A fragment thought to be from a meteor that fell near the Russian city of Chelyabinsk on Feb. 15, which injured about 1,500 people. NASA and others failed to detect the meteor.
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Shock Wave of Fireball Meteor Rattles Siberia, Injuring 1,200(February 16, 2013)
“We’d have a lot more than broken windows, that’s for sure,” the former astronaut, Edward Lu, told a Senate panel in Washington. Dr. Lu, also a former executive at Google, is now the chief executive of the B612 Foundation, a Silicon Valley group that wants to build a privately financed asteroid-detecting space telescope.
About 1,500 people were injured when the roughly 60-foot-diameter meteor exploded high in the atmosphere near the Russian city of Chelyabinsk on Feb. 15. Most of the injuries were caused by flying glass from shattered windows when a shock wave from the explosion — estimated to have been about 30 times more powerful than the atomic bomb that destroyed Hiroshima — hit the city a minute and a half later. “Had that shock wave been a lot closer to a city, it would have caused a lot more damage,” Dr. Lu said.
He also noted that if the so-called Tunguska event — the explosion of a roughly 150-foot asteroid over Siberia in 1908 — had occurred over New York, “whatever the population of New York City is, they’d be gone.”
The Chelyabinsk meteor was not detected by any of the ground-based telescopes, operated by NASA and others, that are surveying the sky for space rocks that are in orbits that could intersect with Earth’s. Those search programs are focused on larger asteroids, James Green, director of the planetary science division of NASA, told the Senate panel, the Science and Space Subcommittee.
So far about 10,000 have been detected, including about 95 percent of the estimated 1,100 that are a kilometer (about 1,000 yards) or more in diameter and have the potential to end civilization. So far, Dr. Green said, no asteroid has been found that poses a threat to the planet.
But Dr. Lu noted that for every asteroid that had been detected, there were probably 100 more that had not been seen, including hundreds of thousands that are the size of the Russian meteor. “Right now, the amount of warning time that we are likely to get from one of these asteroids is zero,” he said.
If a meteor was found to be just days from hitting Earth, there is little that could be done, except perhaps evacuating a city or region. But in response to a question from Senator Ted Cruz of Texas, the ranking Republican on the subcommittee, Dr. Lu said that given enough lead time, there were various ways to divert an asteroid to make it miss Earth entirely, including something as basic as running into it with a spacecraft to nudge it just a bit.
“If you find it early, we have many options,” Dr. Lu said. “Then you only need to change its trajectory by a very tiny amount.”
“The key is, if you don’t know where they are, there’s nothing you can do,” he added.
While some people argue that money would be better spent on more pressing societal problems than on a low-probability event like a civilization-busting asteroid strike, both Mr. Cruz and Senator Bill Nelson, the Florida Democrat who is chairman of the panel, expressed little skepticism about the scientists’ testimony.
“I’m eager for our collective journey to ensure that NASA and all related programs have sufficient resources and sufficient priorities to do what needs to be done,” said Mr. Cruz, who was elected last year with Tea Party backing, in his opening remarks.
Asked after the hearing about the senator’s position on the NASA budget, only a small portion of which goes toward asteroid detection, a spokeswoman for Mr. Cruz said she had no comment.
One difficulty in searching for asteroids from the ground is that the sun often gets in the way, making a small space rock impossible to see. The B612 telescope, called Sentinel, would be oriented in a way that could eliminate that problem. The project is estimated to cost $450 million, and the foundation has a goal of launching the telescope within five years.
While NASA is not providing any money for the Sentinel project, Dr. Green said the agency was offering some technical help.
In a later interview, Dr. Lu said that while his group was busy raising money privately and was not seeking money from NASA, “if they decide that this is something that is of value to them, and they want to have that conversation, then I’d be happy to have that conversation.”
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