Fireball Lights Up Northeast Skies

It was a scene straight out of a sci-fi flick: a bright, fiery object hurtling toward Earth.

The display was more than visual: the object apparently exploded as it fell, prompting calls to 911 numbers from Virginia to New York. And the view was the same from the air as from the ground: pilots reported the phenomenon to air traffic controllers from their cockpits.

It was the second time in 10 days that people in the Northeast were stunned by lights in the sky. Experts are still puzzling over a display of lights over parts of New Jersey earlier this month.

The question of exactly what it was that lighted up the sky Monday night hasn't been answered either, though if it turns out that a burned cornfield in Pennsylvania was caused by the object striking Earth, that could change.

Salladasburg, Pa., Fire Chief Gerald Ross said some people out watching deer saw a fireball and then came out onto the scorched cornfield. He said an area of roughly 25 feet by 20 feet was burned.

"We summoned assistance from the DEP who brought in an air quality and radiation meter and at this point we have found nothing more than background level radiation and air quality readings," Ross said. "Although they are not here to comment, they have found little or no environmental hazard at this time."

At first, the object was thought to be part of a meteor shower. But U.S. Naval Observatory spokesman Geoff Chester said he believed it was something called a bolide, or fireball.

Earth vs. Random Piece of Rock

"It is similar to the shooting stars you see sporadically at night in its appearance, but as far as the physical nature of this object is concerned it's quite different from the periodic meteor showers we get," he told The Associated Press.

"This is a random piece of rock that happened to have the misfortune of being in the same part of space occupied by the Earth at the same time," Chester said. "In this particular case, the Earth won."

Neil de Grasse Tyson, a physicist with the Hayden Planetarium, said he believed it was a meteorite and said the brightness and size of the light as it streaked across the sky were out of all proportion to its likely size.

"Meteors are notorious for being very visible, yet not very large in size," he said.

If it had been as big as it looked to observers up and down the East Coast, scientists would have known it was coming, he said.

A Ball of Fire, Trailing Smoke

Though many people reported that their houses shook as the object seemed to explode, there were no reports of damage from the blast, and aside from the Pennsylvania cornfield, there apparently was no destruction from fragments hitting Earth.

National Weather Service meteorologist Dave Sage said meteorites usually break up into small pieces if they enter Earth's atmosphere.

"I don't believe there's anything to be too concerned about," he said.

Witnesses reported seeing the phenomenon in Virginia, Maryland, Delaware, New Jersey and across New York state, and in many cases dozens of cars pulled off the road to watch as the bright objected streaked across the sky.

"It seemed pretty close," said Pennsylvania witness Peter Biddle. "Coming in at about 30 degrees, it was just a ball of fire with about 6 feet of smoke coming out the back."

Police blocked off parts of central Pennsylvania where chunks of the extraterrestrial rock are believed to have landed. The Associated Press reported broken windows in the area from the explosive thunder-like sounds the object made as it fell, likely a sonic boom.

Happens a Few Times a Month…Somewhere

While witnesses may feel like they saw something truly unique, the Naval Observatory's Chester said bolides occur somewhere in the world two or three times a month.

What makes this one different, he said, was time and location.

"It happened to occur over a very densely populated area, on a beautiful, clear day, smack in the middle of the evening rush hour," he said. ABCNEWS affiliate WPVI in Philadelphia contributed to this report.