* Astronomy

Volcanoes were active on the Moon's surface soon after it was formed, a new study in the journal Nature suggests.
Precision dating of a lunar rock that fell to Earth shows our satellite must have had lava erupting across its vast plains 4.35 billion years ago.
This is hundreds of millions of years earlier than had been indicated by the rocks collected by Apollo astronauts.

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Mare-type volcanism developed on the moon soon after its formation, according to a new study of a meteorite.
The findings will help researchers understand how planets develop in their early stages, the study authors say.
An international team of researchers examined a 13.5-kilogram moon rock (Kalahari 009) found in the southern African country of Botswana. The meteorite was confirmed as originating on the Moon by the telltale signature of oxygen isotopes and ratio of iron to manganese in two volcanic minerals, olivine and pyroxene.

"It seems like it came upon Earth relatively recently, unlike many lunar meteorites" - team member Mahesh Anand of Open University in Milton Keynes, England.

The meteorite was found by local people near the village of Kuke, in the grasslands of the Kalahari Nature Reserve in In 1999. It probably landed about 200 to 300 years ago. The mare basalt meteorite was probably blasted free from the moon when an asteroid hit the lunar surface.
Analysis of phosphate in the meteorite dates the rock at 4.35 billion years, give or take 150 million years. The age shows that volcanoes had already begun erupting just 150 million years after the formation of the first lunar crusts.
Earlier studies, based on rocks collected during the Apollo mission, suggested that the moon's volcanic activity occurred after 3.9 billion years ago.
The new study appears this week in the journal Nature.

Title: Cryptomare magmatism 4.35 Gyr ago recorded in lunar meteorite Kalahari 009
Authors: Kentaro Terada, Mahesh Anand, Anna K. Sokol, Addi Bischoff & Yuji Sano

The origin and evolution of the Moon remain controversial1, with one of the most important questions for lunar evolution being the timing and duration of basaltic (mare) magmatism. Here we report the result of ion microprobe UPb dating of phosphates in a lunar meteorite, Kalahari 009, which is classified as a very-low-Ti mare-basalt breccia. In situ analyses of five phosphate grains, associated with basaltic clasts, give an age of 4.35 plusminus 0.15 billion years. These ancient phosphate ages are thought to represent the crystallization ages of parental basalt magma, making Kalahari 009 one of the oldest known mare basalts. We suggest that mare basalt volcanism on the Moon started as early as 4.35 Gyr ago, relatively soon after its formation and differentiation, and preceding the bulk of lunar volcanism which ensued after the late heavy bombardment around 3.8-3.9 Gyr. Considering the extremely low abundances of incompatible elements such as thorium and the rare earth elements in Kalahari 009 and recent remote-sensing observations illustrating that the cryptomaria tend to be of very-low-Ti basalt type, we conclude that Kalahari 009 is our first sample of a very-low-Ti cryptomare from the Moon.

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The next time you take a moonlit stroll, or admire a full, bright-white moon looming in the night sky, you might count yourself lucky. New observations from NASA's Spitzer Space Telescope suggest that moons like Earth's -- that formed out of tremendous collisions -- are uncommon in the universe, arising at most in only 5 to 10 percent of planetary systems.

"When a moon forms from a violent collision, dust should be blasted everywhere.  If there were lots of moons forming, we would have seen dust around lots of stars -- but we didn't" - Nadya Gorlova of the University of Florida, Gainesville, lead author of a new study appearing Nov. 20 in the Astrophysical Journal.

It's hard to imagine Earth without a moon. Our familiar white orb has long been the subject of art, myth and poetry. Wolves howl at it, and humans have left footprints in its soil. Life itself might have evolved from the ocean to land thanks to tides induced by the moon's gravity.
Scientists believe the moon arose about 30 to 50 million years after our sun was born, and after our rocky planets had begun to take shape. A body as big as Mars is thought to have smacked into our infant Earth, breaking off a piece of its mantle. Some of the resulting debris fell into orbit around Earth, eventually coalescing into the moon we see today. The other moons in our solar system either formed simultaneously with their planet or were captured by their planet's gravity.

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A new computer model, based on gravitational interaction with Jupiter and Venus, may explain the moon's eccentric orbit as it travels along an elongated oval-shaped path around Earth.
Matija Cuk, an astronomer at the University of British Columbia in Canada, developed the computer model in an attempt to explain these lunar eccentricities.

"I asked myself-was the orbit of the moon early on more circular than now, or was it just like now, or more eccentric?" - Matija Cuk.

His model, detailed in the Sept. 12 issue of the journal Science, suggests that Venus and Jupiter have elongated the moon's orbit slightly through a phenomenon called gravitational resonance. The planets affected the moon with their gravities, exerting a strong pull on the moon at some time during our solar system's past when the two planets' orbital periods were aligned with the moon's orbit.
The gravitational resonance occurred because the moon orbits the Earth in an elliptical path, and the moon rotates counterclockwise as it treks around the Earth on a nine-year cycle as a result of interactions with the sun. At some point in the past, however, the duration of this "lunar precession" was about 12 years, which is approximately equal to the time it takes Jupiter to go once around the sun.
When the lunar precession and Jupiter's orbital period were equal, about 1 billion years ago according to the new model, Jupiter's small gravitational tug on the moon became amplified with each cycle.
According to the model, the moon underwent the same thing with Venus about 2 to 3 billion years ago. If not for those interactions, the moon's orbit would be closer to circular, and it would not seem to shrink and grow, or speed up and slow down, so much as it traverses the night sky.

Source:Xinhua