NASA says the asteroid, which could have wiped us out in 2040, will miss us by about half a million miles.
The asteroid is 140 meters (460 feet) in diameter, and will get no closer to Earth than 890,000 kilometers (553,000 miles), more than twice the distance to the moon.
Previously uncertainties about the orbit of the asteroid, designated 2011 AG5, allowed for less than a 1 per cent chance it would strike the earth in February 2040.
To better understand the odds, NASA recruited astronomers from the University of Hawaii at Manoa to observe the asteroid over several days in October.
Hawaii’s observations, done using a Gemini 8-meter telescope, reduce the orbit uncertainties by more than a factor of 60.