Mineral Seen as Clue on Moon Origin Found by Japan Lunar Lander

Tokyo, May 28 (Jiji Press)--Japan's first successful lunar lander has taken an image of a rock containing the mineral olivine, giving rise to expectations that it may offer a clue on the moon's origin.

The Japan Aerospace Exploration Agency's Small Lander for Investigating Moon, or SLIM, achieved a precision landing near an impact basin thought to be an exposed area of the lunar mantle. Its robot took spectroscopic pictures of 10 rocks, each named after a dog breed, with its multiband camera.

A team of researchers from Ritsumeikan University, Aizu University and others announced at a Japan Geoscience Union meeting in Chiba, east of Tokyo, on Monday that a rock named Dalmatian richly contained olivine.

The mineral is the main component of the Earth's upper mantle and believed to be that of the lunar mantle, which makes up 90 pct of the moon's mass.

The giant impact hypothesis, the most widely accepted theory for the origin of the moon, suggests that it was formed when another celestial body collided with the primitive Earth.

A comparison of olivine from the moon's mantle with that of the Earth's is necessary to understand how the moon was born.

"Further examination is required" to determine whether the moon's olivine actually originated from the mantle, Kazuto Saiki, professor at Ritsumeikan University, said. "But the presence of olivine has been confirmed," he noted.

The researchers also learned that features varied among the rocks, with plagioclase a major component of one called Beagle.

"The rock (containing olivine) looks very different from those coming from the crust and other places," Aizu University Prof. Makiko Otake said.

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