New York (PTI): An asteroid measuring several feet in diameter is expected to enter the earth's atmosphere over northern Sudan before dawn today setting off a display of natural fireworks in the sky.

But it is unlikely any sizable fragments will survive the fiery passage through earth's atmosphere, American space agency NASA said.

"We estimate objects of this size enter earth's atmosphere once every few months," said Don Yeomans of the Near-Earth Object Office at NASA's Jet Propulsion Laboratory in Pasadena.

"The unique aspect of this event is that it is the first time we have observed an impacting object during its final approach."

The space rock, designated as 2008 TC3, will travel on an eastward trajectory that will carry it towards the Red Sea.

"Observers in the region could be in for quite a show," Yeomans said. "When the object enters the atmosphere, it could become an extremely bright fireball."

The small space rock first was observed by the Mount Lemon telescope of the NASA-funded Catalina Sky Survey early yesterday.

NASA detects and tracks asteroids and comets passing close to earth. The Near-Earth Object Observation Programme, commonly called "Spaceguard," plots the orbits of these objects to determine if any could be potentially hazardous to our planet.