SYDNEY, Australia (Reuters) - Even for an alien it was a poor shot -- an intergalactic out-of-bounds in the water, irretrievably embedded in the earth, for a one stroke penalty.

The mysterious object which slammed into an Australian dam, leaving a large crater and attracting nationwide attention, has turned out to be a meteorite -- but only the size of a golf ball.

Police divers on Friday recovered sediment and fragments from the dam at Guyra, 400 km (250 miles) north of Sydney, which geologists believe came from a ``golf-ball'' size meteorite which landed sometime between Monday and Wednesday.

Despite its small size, the force of the impact left a 15-meter (50 ft) long and 6-meter (20 ft) wide crater in the dam and the meteorite penetrated the bottom of the dam.

"The meteorite has penetrated the mud at the bottom of the dam and is now embedded in about four meters (13 ft) into granite and unable to be removed,'' said a police spokeswoman.