[QODLink]
Americas
Astronomers: Moon is shrinking
Scientists say shrinkage negligible and unlikely to affect the earth in any way.
Last Modified: 21 Aug 2010 11:06 GMT
Astronomers said that the shrinkage will not affect the planet [EPA]

The moon is shrinking but it will not be disappearing any time soon and its shrinkage will not affect the earth in any way, astronomers say.

Reporting on Thursday in the US journal Science, the astronomers said they had found previous undetected landforms which indicate that the earth's satellite has been shrinking but by only a tiny amount.

Relative to the moon's age, estimated at around 4.5 billion years, the contraction is recent, occurring less than a billion years ago, and is measured at about 100 metres.

Thomas R Watters of the Centre for Earth and Planetary Studies at the Smithsonian's National Air and Space Museums said scientists have identified 14 landforms called lobate scarps scattered over the surface of the moon.

The scarps had previously been noted at the moon's equator, but this is the first evidence in other areas, indicating they result from a global process.

Dr Francisco Diego, a fellow of the Royal Astronomical Society in London, agreed with his US colleagues, saying the shrinking was "almost negligible".

"It is an interesting fact to see how these objects in the solar system develop and evolve for us to know ... the origins of these bodies and how they are behaving," he told Al Jazeera.

No large craters

The Science study calls the scarps "evidence of recent thrust faulting on the moon". But this is planetary science, where "recent" can mean a billion years ago.

The scarps, or cliffs, extend across some small craters, and small craters tend to be obliterated over time, Watters said.

In addition, there are no large craters imposed on top of the scarps, another indication they are relatively recent, in planetary terms, he said.

"One of the really cool parts of this ... the faults are so young-looking that you can't escape the possibility that this contraction occurred recently, and could indicate that the moon is still active," he said.

The size of the scarps indicates a shrinkage in the size of the moon of about 100 metres, which would not be nearly enough to be noticed with the naked eye. The moon is about one-fourth the size of the earth in diameter.

The scarps range up to 10 metres high and a few kilometers long, according to Watters.

By comparison, the planet Mercury has much larger scarps indicating considerably more shrinkage over time.

Source:
Al Jazeera and agencies
Topics in this article
People
Country
Organisation
Featured on Al Jazeera
The author argues that in the new economy, it's people, not skills or majors, that have lost value.
Colleagues of detained Al Jazeera journalists press demands for their release, 100 days after their arrest in Egypt.
Mehdi Hasan discusses online freedoms and the potential of the web with Wikipedia founder Jimmy Wales.
A tight race seems likely as 814 million voters elect leaders in world's largest democracy next week.
Featured
Activists say 'Honor Diaries' documentary exploits gender-based violence to further an anti-Islamic agenda.
As Syria's civil war escalates along the Turkish border, many in Turkey are questioning the country's involvement.
Treatment for autism in the region has progressed, but lack of awareness and support services remains a challenge.
The past isn't far away for a people exiled from Crimea by Russia and the decades it took to get home.
New report highlights plight of domestic helpers in the United Kingdom, with critics comparing it to kefala system.
join our mailing list