Two mysterious metallic spheres that fell last week in South Africa were indeed from outer space, but their origins are officially terrestrial in nature.

Nick Johnson, NASA chief scientist and manager of the space agency's orbital debris program, told a local talk radio station Monday that the two objects had originally been part of a Delta rocket launched in 1996.

NASA had expected debris to land in the area, he said, stressing that circumstantial evidence indicated that the objects were indeed the prosaic space junk the agency had been anticipating.

The first object landed in a Cape Town area farm Thursday, leaving an impact mark in the soil inches deep. Weighing about 65 pounds [30 kg], the metallic sphere was white hot when it landed and contained what eyewitnesses described as "bolts."

The second, larger object weighed nearly twice as much -- 110 pounds [55 kg] -- and was shaped more like an egg than a sphere when it crashed into another farm Sunday. Observers reported that the object was about 4 feet long by 3 feet in diameter [1.3 meters x 1 meter] and was similarly too hot to touch.

Local police authorities retrieved both objects for study.