A fast-moving asteroid discovered by an amateur Chinese astronomer came close to Earth on Saturday in an orbit forecast by international scientists.

The asteroid, 15 meters in diameter, was spotted by Yu Jun, a doctoral student at the Chinese University of Science and Technology in Hefei, capital of east China's Anhui Province.

Yu discovered the asteroid on April 1, while reviewing telescope images on the Internet for the University of Arizona's Spacewatch program.

The program allows volunteers to spot fast-moving space objects, or FMOs, by logging onto a Web site and downloading images taken by telescopes at Kitt Peak National Observatory, 90 kilometers southwest of Tucson.

While some observers scroll through thousands of pictures to discover an asteroid, Yu said he had only looked at 27 images before he spotted this one -- named 2005 GT on April 3 by the Minor Planet Center, the official oversight body for such observations. It was the first FMO discovered by a Spacewatch observer on the Chinese mainland.

The asteroid missed the Earth by 6 million kilometers, but experts say it wouldn't have done much more than offer a pretty light show even if it had been aimed directly at Earth, as it would have burned up in the upper atmosphere.

"It's a pleasant surprise indeed," said Yu in an interview with Xinhua on Sunday. "I thought it was an April Fool's joke when I received an e-mail from the University of Arizona to congratulate me on my discovery."

Yu said he majors in theoretical astronomy but is very interested in astronomical observations.

Spacewatch, launched in September, 2003, primarily studies the movement of asteroids and comets. Volunteers fill an important niche, while researchers at the University of Arizona and automated computers track larger objects in space.

The program has used more than 1,000 volunteers worldwide and at least 20 FMOs have been discovered.

The program's major goals include searcing for potential destinations for space missions and identifying asteroids larger than a kilometer in diameter and heading toward Earth.

An impact by an asteroid that size could cause a global catastrophe.