‘Killer Asteroid’ could strike earth by 2036, experts say

SAN FRANCISCO – In the movie “Armageddon,” Bruce Willis saves the world from a killer asteroid by landing on the rock’s surface, drilling a hole and detonating a nuclear weapon inside.\nBut that’s Hollywood. What could really be done about a similar real-world threat? A panel of experts at a recent meeting of the American Association for the Advancement of Science in San Francisco posed that question.\nTwo years ago, NASA identified an asteroid 300 meters in diameter, dubbed Apophis. It will have a close brush with Earth in 2029 and a possible collision in 2036. And Apophis could be just the first in a long line of possible asteroid threats. Congress has ordered NASA to step up its detection of nearby asteroids over the next 12 years.\nWhile “Killer Asteroids,” the title of the association’s news release, sounded like a science-fiction movie, NASA scientist David Morrison assured the audience the asteroid-impact prediction was no joke.\n“We’re talking about real asteroids, a real survey, real circumstances,” he said.\nScientists have already ruled out the possibility that Apophis will hit Earth on its first pass in 2029. However, if it passes through a certain “keyhole,” or narrow slot of space, it could return to Earth in 2036 for a collision.\nIn this scenario, Bruce Willis’ method of blowing up the asteroid won’t do us much good, said NASA astronaut Edward Lu during the event in San Francisco. Asteroids are made of rocks, pebbles and boulders that could break up into fragments of unpredictable sizes. A fragment 60 meters in diameter could level a region the size of the San Francisco Bay area.\nBut there are preventative options. Lu proposes the use of a “gravitational tractor,” a small spacecraft that would hover either just behind or in front of the asteroid. The spacecraft would exert a tiny amount of gravitational force, gently tugging the asteroid into another orbit. Lu calls this strategy the “Cosmic Do-No-Harm Principle.”\nThe chance that scientists will have to unleash a gravitational tractor on Apophis is roughly one in 45,000. But even so, Morrison said, “you haven’t heard the last of the killer asteroids.” NASA expects to increase its rate of asteroid detection by 50 to 100 times, potentially identifying up to 20,000 new asteroids by 2020. This could mean a roller-coaster ride for the public and press as new threat asteroids pop up from month to month.\nThe public will also have to deal with uncertainty as collision probabilities shift from day to day. Scientists at NASA’s Jet Propulsion Laboratory predict the path of asteroids based on incoming data from telescopes. When new data comes in, the probability of collision can also shift, just as the weather forecast of a hurricane grows more and more accurate as the hurricane approaches.\nUnlike other natural disasters, asteroids can be avoided.\n“We can’t prevent a hurricane and we can’t prevent a tornado, but we can prevent an asteroid impact,” said former Apollo astronaut Russell Schweickart to the audience during the event. “If we don’t do that, we’re not that far past the dinosaurs.”