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RE: The Moon
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 With binoculars, examine the rugged face of the Moon. It is pocked with thousands of impact craters from interplanetary asteroids and comets. Ever wonder why Earth, a much bigger target, apparently has so few craters? They're so rare that a pristine example, the Barringer Meteor Crater in Arizona, is actually a tourist attraction. Did Earth just get lucky and dodge the heavy artillery?

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Lunar Transient Phenomena
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If you stare at the Moon long enough, you start seeing things. "82 things to be exact," says Bill Cooke, leader of NASA's Meteoroid Environment Group. That's how many "transient phenomena" the group has video-taped since they started monitoring the night side of the Moon in Nov. 2005.

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The moon may not be just a chip off the old planetary block. It could have formed at the same time as Earth from the same primordial stuff.
The current theory says that the material that now forms our moon was ejected when Earth was struck by another planet-sized body. But Peter Noerdlinger at Saint Mary's University in Halifax, Canada, says this theory has problems.

"The collision has to be implausibly gentle. You practically need someone to hold a Mars-sized object just above Earth and drop it, to avoid messing up Earth's orbit."

The simpler idea that Earth and the moon were both created from the same gas cloud had been rejected because it could not explain why Earth formed an iron core and the moon did not. Now, Noerdlinger has an answer for that
He suggests that the proto-moon did have an iron core, but that the satellite was ripped apart in a close encounter with Earth. His calculations show that iron from the core would be pulled towards Earth, while the remains of its rocky outer shell reassembled into our iron-free moon.

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Deep down, the moon may be more like Earth than scientists ever thought.
A new moon-rock study suggests the satellite has an iron core. The findings add weight to the theory that the moon formed from debris thrown off when a Mars-size object collided with a young Earth .

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The Moon has been seen huffing and puffing, remnants of a once very active satellite, scientists reported today.
It’s believed that the Moon hasn’t experienced any volcanic activity for at least three million years, but a new look at some old evidence suggests otherwise.
Examining photographs and data from the Apollo missions, scientists noticed that volcanic gas has been released from the lunar surface within the last 1 million to 10 million years.

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Shackleton crater
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This image, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows crater Shackleton on the Moon.
AMIE obtained this image on 13 January 2006 - close to the time of lunar southern Summer - from a distance of 646 kilometres over the surface and with a ground resolution of 60 metres per pixel.
Shackleton crater lies at the lunar South Pole, at 89.54° South latitude and 0° East longitude, and has a diameter of 19 kilometres.

Shackleton
Credits: ESA/Space-X

SMART-1 monitored this area almost every orbit. This will allow to produce very high resolution maps of the area as well as illumination maps. The long shadows that surround the crater make it very hard to observe. The analysis of the data obtained allowed a very detailed map of its rim, surrounding ejectas and craters.
SMART-1 also made long repeated exposures to see inside the shadowed areas. The purpose was detecting the very weak reflected light from the crater rims, and therefore study the surface reflection properties (albedo) and its spectral variations (mineralogical composition). These properties could reveal patchy ice surface layers inside the crater.
On the 2-kilometre wide inner edge of the crater ridge, at times barely visible from Earth, astronomers using ground radio-telescopes have recently reported they were not able to detect a distinctive signature of thick deposits of ice in the area. Earlier measurements by NASA's Lunar Prospector reported of hydrogen enhancement over large shadowed areas.

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Water Ice on the Moon
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This radar image of the south pole region of the moon is about 250 km by 100 km. Shackleton crater (A) is 19 km in diameter. The Lunar Prospector orbiter impacted Shoemaker crater (B), 51 km in diameter. The south pole is about on the centre of the left rim of Shackleton.

LunarPole
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Credit D. Campbell (Cornell), B. Campbell (Smithsonian) and L. Carter (Smithsonian)

The image was made in April 2005 by transmitting from Arecibo Observatory in Puerto Rico at 13 cm wavelength and receiving the radar echo with the Robert C. Byrd Green Bank Telescope in West Virginia. The underlying resolution of the image is about 20 m, the highest resolution radar image ever made of the moon.

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-- Edited by Blobrana at 15:49, 2006-10-19

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Early radar data hinted that water ice might exist in the permanent shadows of craters at the lunar poles, and the neutron spectrometer on board the Lunar Prospector in 1998 detected the telltale signature of hydrogen within the moon's surface. If that hydrogen is locked up in the form of H2O, then as much as 26 billion gallons of water could be frozen there.
To help settle the question, astronomer Donald Campbell of Cornell University and his team trained the world's most powerful radio observatory--the Arecibo Telescope in Puerto Rico--on the moon's south pole, particularly its large Shackleton Crater, searching for signs of water like those detected on Mercury and elsewhere.

"Ice essentially lights up under radar. It preferentially reflects the light back at the radar like a highway sign. When we looked at the poles of the moon we did not see the same sort of signature" - Donald Campbell

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Despite evidence from two space probes in the 1990s, radar astronomers say they can find no signs of thick ice at the moon's poles. If there is water at the lunar poles, the researchers say, it is widely scattered and permanently frozen inside the dust layers, something akin to terrestrial permafrost.

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The controlled crash of NASA's Lunar Prospector spacecraft into a crater near the south pole of the Moon on July 31 produced no observable signature of water, according to scientists digging through data from Earth- based observatories and spacecraft such as the Hubble Space Telescope.

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Recent data from the Clemetine mission supports the possibility of the presence of water ice at the south pole of the Moon. In permanently shadowed regions on the surface of the Moon, the temperature is a constant -233 degrees centigrade. These temperatures are cold enough to permanently trap water molecules that have been introduced by comets or water-bearing meteoroids.

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Crater Pentland
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This high-resolution image, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows an area close to crater Pentland on the Moon.

crater Pentland

AMIE obtained this sequence on 18 March 2006 from a distance of 573 kilometres from the surface, with a ground resolution of 52 metres per pixel. The imaged area is centred at a latitude of 67.7º South and longitude 18.3º East.
During the course of its mission, Smart-1 orbited the Moon in a highly elliptical orbit, varying its distance to the lunar surface roughly between 500 and over 2000 kilometres. This particular image was taken from really close by.

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