(CNN) - An asteroid will speed by Earth this fall, but there's no need to worry.
NASA's Planetary Defense Coordination Office said the flyby won't put anyone in danger. Instead, it's an opportunity to test the agency's Planetary Defense Systems in the event of actual asteroid threat.
The asteroid swinging by Earth on Oct. 12 isn't expected to get closer than 4,200 miles from Earth's surface. It's somewhere between 30 to 100 feet in size, making it small by asteroid standards.
While scientists know that asteroid is unlikely to impact Earth, they don't know much else about the rock's trajectory.
NASA tracked the asteroid for seven days after discovering it in October 2012, but that's the last time the organization had eyes on it. In the past five years, the asteroid has been too far away.
The Planetary Defense Coordination Office is investigating different techniques for stopping asteroids from striking the planet. They include using objects to change its trajectory by bumping it or changing its gravitational pull.
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