Aug 23, 2010

The moon is shrinking, say scientists


“Astronomers have declared that the moon is shrinking after spotting wrinkles all over the lunar surface. The tell-tale contraction marks were discovered by US scientists who examined thousands of photographs of the moon’s surface taken by a Nasa orbiter.

Some of the wrinkles are several miles long and rise tens of metres above the dusty terrain. Researchers believe they arise from the moon decreasing in size by around 200 metres across its diameter. The moon’s mean diameter is generally calculated to be 2,159 miles.

The prospect of a shrinking moon is not new to planetary experts. When the moon formed it had a hot core, much like that of the Earth, which caused it first to expand and then contract as it cooled down.

The latest findings suggest the moon could still be cooling, a process that causes the surface to compress and form the wrinkle-like features, known as lobate scarps.

A team led by Thomas Watters at the Smithsonian Institution in Washington DC studied high-resolution images of the moon taken over the past year by Nasa’s latest moon probe, the Lunar Reconnaissance Orbiter. The spacecraft cameras provide the most detailed images of the moon ever taken from orbit.

Fourteen lobate scarps were identified, at sites as far apart as the lunar equator and near the poles. The features are so pristine scientists think they could be no more than a billion years old.

“Not only could they be indicating recent contraction of the moon, they may be indicating that the moon is still contracting,” said Watters. “Until now, we really had no evidence of cooling and the contraction of the moon that would go along with it. This isn’t anything to worry about. The moon may be shrinking, but not by much. It’s not going anywhere.”"

Read more at The Guardian

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