"Back in 2004 when this asteroid was discovered there was concern that it had a relatively high probability of impacting Earth, a 1 in 45 chance during the 2029 flyby," said Slooh president Patrick Paolucci. "Fortunately they were able to determine that was inaccurate. But on that next approach in 2029, it's still going to be closer [to Earth] than our satellites. That's really why this event is on our radar."

Scientists will watch Apophis to better fine-tune its future path. Wednesday's pass could even influence the miniscule possibility (1 in 250,000 by NASA estimates) that the 885-foot (270-meter) rock might actually hit Earth in 2036. It would happen only in the extremely unlikely and unlucky event that Earth's