An asteroid 30 to 50 feet across will pass by the Earth at just more than one-third the distance between the Earth and the moon on Wednesday. That's the closest near-Earth object approach currently known between now and the flyby in 2024 of a similar-size object known as 2007 XB23.

The new asteroid, called 2010 AL30, was discovered by the NASA-funded Lincoln Near-Earth Asteroid Research program, and announced Monday by the Minor Planet Center at the Smithsonian Astrophysical Observatory.

The short amount of time between the spotting of the object and its near intersection with Earth is a good reminder that humans don't know every object that could come hurtling out of space and collide with our planet.

"Visitors frequently ask me if I worry about the NEOs that I measure," wrote Dr. P. Clay Sherrod of the Arkansas Sky Observatories, on a forum thread discussing the asteroid. "My response: 'I don't worry about those that we keep up with.... I am more concerned about the ones we never see coming."

To see how close the asteroid will get, check out this animation of the asteroid's Earth approach (.avi) by Gerhard Dangl, an Austrian astronomer.

It should be noted that an asteroid this small probably would not cause major damage were it to impact Earth's atmosphere, and would probably burn up before it reached the planet's surface.

The new object will remain about three times farther away from Earth than Apophis, which has been the subject of much recent discussion, will in 2029.

Images: Ernesto Guido & Giovanni Sostero

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