Without "a few years" warning, humans currently have no capacity to stop an asteroid on a collision course with the planet, scientists told a Senate panel Wednesday.
"Right now we have no options," said former astronaut Ed Lu. "If you dont know where they are, there's nothing you can do."
Scientists are calling for continued funding and support for NASA satellites and observation programs that look for "near Earth objects." The scenario from Hollywood blockbuster Armageddon is on the minds of lawmakers after two hulking rocks exploded in the air over Russia in February. More than 1,000 people were injured, bringing the risks of future incidents and measures to prevent them into clearer focus.
"I was disappointed that Bruce Willis was not available to be a fifth witness on the panel," joked Ted Cruz, R-Texas, during the hearing.
While scientists put the odds of asteroids one kilometer in diameter or larger colliding with the earth as "once every few thousand year" event, they said cuts in space funding to monitor and detect space rocks could have devastating consequences.
"What [the film Armageddon] did was basically convince the American people that if anything bad happened, people would get in a shuttle and fix it," said Joan Johnson-Freese, a professor at the U.S. Naval War College. "That is myth. That is not reality."
Scientists were simply sharing a grim reality NPR and others have written about in recent weeks that the rules of physics mean there's almost no way to stop asteroids and debris from hurtling toward earth. It didn't stop the doomsday-scenario questioning from Sen. Bill Nelson, D-Florida:
"What would an asteroid that is a kilometer in diameter, what would it do if it hit the earth?," Nelson asked.
"That is likely to end human civilization," said Lu, who is now CEO of the B612 Foundation, which aims to hunt devastating asteroids.
Decades of lead time is the only way to prevent that level of destruction, said scientists. With decades of advance notice, Lu said, American astronauts currently do have the capacity to destroy or make small changes to the trajectory of flying space objects to keep them from hitting earth. But detection requires investment, they said.
"It's important to know what we're up against, and this decade in particular is great for us to do the research necessary that will contribute to potential mitigation concepts," said James Green, NASA's planetary science director.
Lu estimates there's a 30 percent chance this century of relatively smaller asteroids hitting a "random location" on the earth to create a five megaton impact. Casualties would depend on the population of the area of impact.
If detected early enough, the cost of a mission to prevent a hit would cost at least a billion dollars, Lu said. "But ... you'd have to compare that against the losses of a massive, megaton impact."