NASA: Russian claims of Apophis collision with Earth exaggerated
Apophis is the “doomsday asteroid” that Russian astronomers predict will collide with Earth in 2036. The Russians said when Apophis makes a routine pass close to Earth in 2029, it could fly through a “gravitational keyhole” that will put it on a collision course in a later orbit. NASA dismissed the probability of an Apophis/Earth collision, but it is working on methods to deflect doomsday asteroids.
Odds of Apophis collision course slim
The chance of an Apophis collision with Earth was first announced by NASA scientists in 2004. Initial observations hinted that Apophis, about the size of a cruise ship, could collide with Earth in 2029. A deeper mathematical investigation of the probabilities virtually ruled out any chance of an Apophis/Earth collision. Last month Russian astronomers said that during its 2029 fly-by, Apophis could pass through a pinpoint in space known as a gravitational keyhole that would alter its course enough to hit the bullseye in 2036. A NASA official didn’t deny the Russian claims but noted that the odds of Apophis passing through the gravitational keyhole are one in 250,000.
Apophis impact effects
Apophis will make a very close pass to Earth in late 2012 — about 18,000 miles, which is below the altitude of geosynchronous satellites stationed in orbit. When it was first spotted, the odds of an Apophis/Earth collision were calculated at one in 233. The odds reached one in 37 until observations over time reduced them to one in 45,000. If something were to alter the asteroid enough during its 324-day orbit around the sun so that it hit Earth, the 27,000-metric ton rock would release 510 megatons of impact energy. The explosion would be equivalent to 3,400 times the energy released by the U.S. atomic attack on Hiroshima, Japan in 1945.
Asteroid deflection strategies needed
Soon after Apophis caused such a stir, Congress sent NASA a mandate in 2005 that it must discover 90 percent of near earth objects 140 meters in diameter or greater by 2020. The money NASA needs to do that is far greater than the $4 million a year currently spent. Perhaps just as important as spotting potential Earth/asteroid collisions is planning a means to prevent them. Former astronaut Rusty Schweickart, an outspoken advocate of asteroid deflection research, has said the technology currently exists. The hard part is fostering the international cooperation required to save Earth when the time comes.