More than 100,000 asteroids hurtle past our planet. But only one—the one detected so far—may hit us in the next 30 years. Apophis, the ancient Egyptian god of darkness.
Detected in 2004 , all alarms went off, the calculations indicated that he could hit earth on Friday the 13th of April 2029. Further observations showed that will not happen. Scientists are 99.7 percent certain it will pass at a distance of 18,800 to 20,800 miles. In astronomical terms, 20,000 miles is a mere stone's throw, well inside the orbits of Earth's many geosynchronous communications satellites.
However, and here is the bad news, scientists calculate that if Apophis passes at a distance of exactly 18,893 miles, it will go through a "gravitational keyhole." This small region in space--only about a half mile wide, or twice the diameter of the asteroid itself--is where Earth's gravity would perturb Apophis in just the wrong way, causing it to enter an orbit that will will put earth on its way and set potentially catastrophic asteroid impact precisely seven years later, on April 13, 2036.
Well, is a doomsday scenario. According to projections, an Apophis impact would occur somewhere along a curving 30-mile-wide swath stretching across Russia, the Pacific Ocean, Central America and on into the Atlantic. The most likely target, though, is several thousand miles off the West Coast, where Apophis would create a 5-mile-wide, 9000-ft.-deep "crater" in the water. He would hit with a force result of a 28,000 mph entry releasing a energy of 65,000 Hiroshima bombs an a 800-ft. tsunami.
In 2013 Apophis will swings by Earth in prime position for tracking by the 1000-ft. Via the radio telescope in Arecibo, Puerto Rico,this data will probably rule out a keyhole hit in 2029.
In addition to the 2029 encounter, Apophis will likely make two other potentially dangerous close passes to Earth later this century, researchers said — though odds of an impact are currently remote in both cases.
In April 2036, the asteroid will come within about 18,300 miles (29,450 km) of Earth, with a 1-in-250,000 chance of hitting us. For the 2068 pass, the odds are even smaller — about 1 in 333,000.
So lets not think about apocalypse just yet, and even now the calculations show a 45,000-to-1 probability that in 2029 Apophis will pass close enough to make us worry.
But more observations are needed to really pin down where Apophis is headed, in case its orbit is disturbed.