A bright, fiery object darted across the northern horizon Tuesday evening, lighting up both the sky and some government switchboards from New York to Virginia as viewers sought to assure themselves all was well.

The 10- to 15-second display apparently was caused by a meteor as it plunged through the atmosphere at almost 17 miles a second and vaporized, producing a technicolor streak of red, blue, green, orange and pink.

Although the object could be seen up and down the East Coast, it probably weighed less than 4 ounces and was smaller than a fist, scientists said.

Even so, its passage was brilliant enough to prompt citizens up and down the 200-mile New York-to-Washington corridor to telephone local authorities.

"We had people calling in saying it was a red glow, a pink glow, and that Baltimore was under attack," Paul Foley, Baltimore-Washington International Airport operations manager, told reporters.

The cause of the excitement was believed to be a bit of debris from a long-dead comet that once scythed through the solar system every eight or so years. According to John A. O'Keefe, a geophysicist with the Goddard Space Flight Center, once a year the earth passes through the detritus of the old comet, some of which incinerates as it hurtles through the atmosphere.

"It's called the Kappa Cygnid [meteor] shower," said O'Keefe. "It was at its peak between Aug. 18 and Aug. 22 this year.

"Most meteors are estimated to be about the size of a pea or smaller," said O'Keefe. "This was a bit bigger. It was a nice, bright fireball, but it probably wasn't big enough to reach earth."