LACON - At 5:28 p.m. Tuesday, Morgan County 911 lines began ringing. A brilliant lime-green light had appeared, callers said, possibly a downed aircraft.

Callers to The Daily described the same thing, some saying they saw an object falling from the sky and breaking into pieces before the light appeared.

No airplanes crashed, and astronomers said the event was probably a "bolide," a random meteor that could have been natural or man-made.

Morgan County Sheriff Chief Deputy Mike Corley said the reports came from southern Morgan County and Cullman County. Firefighters and various police agencies searched the area but found no crash site.

"(We found) no fires, no explosions or anything to explain it," said Corley. "It was like a falling star."

Decatur astronomer Loren Ball said the bolide likely came from "space junk." He said the North American Aerospace Defense Command is tracking 9,000 pieces of man-made junk including nuts, bolts, gloves and pieces of expired satellites that, because of friction with the upper atmosphere, are gradually approaching Earth.

The lime-green color, Ball said, is consistent with the color that would come from burning aluminum as it entered Earth's atmosphere.

The fact that the object broke into pieces is no surprise, whether the object was natural or man-made. Moving at 10 to 40 miles per second, it would generate tremendous energy, much of it in the form of light. He said a bolide the size of a golf ball generates enough light to trigger calls to the media.

"Something like this happens every day, but there are not always people around to see it," Ball said.

Space junk

According to some studies, there are 4 million pounds of space junk - as many as 110,000 objects larger than 1 centimeter - in low-Earth orbit. They provide a brilliant display on Earth, but can be hazardous to astronauts.

A small speck of paint from a satellite shooting around the Earth once dug a quarter-inch pit in a space shuttle window.

Earth's atmosphere extends 250 miles above its surface, Ball said, a fact that forces the International Space Station and the Hubble Space Telescope to periodically correct their orbit so they won't be pulled into a downward spiral.

Gene Byrd, professor of astronomy at The University of Alabama, said the sightings were too late to be explained by a meteor shower that took place last week.

Bolide explanation

He said the composition of the bolide could explain its greenish color, but the human eye might also explain it. The eye has greater sensitivity to blue and green colors, he said.

Byrd's guess was that it was "a large, sporadic meteor." He said such meteors occasionally emit a sonic boom, and usually are rock fragments from the asteroid belt.

In the 1950s, he said, a small meteor actually struck a woman in Sylacauga, sending her to the hospital with a severe bruise. Astronomers believe a 10-mile-wide meteor that hit Mexico caused the extinction of the dinosaurs, Byrd said.

Corley said he saw the event from his home.

"It did have an unusual color. It had a bright, glowing, lime-green color to it," Corley said.

The Alabama sightings came a day after a similar green fireball was seen in the skies above Australia.

Meteorologists there identified the object as a meteor, likely produced as the Earth passed through the tail of the comet Tempel-Tuttle according to news reports.

Last week, a Russian cosmonaut hit a golf ball into orbit from the International Space Station as part of a publicity campaign to raise money for the Russian space program.

The golf ball joined the other pieces of space junk that will eventually burn up in the upper atmosphere.