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TOPIC: The Moon
Blobrana


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Title: Did a large impact reorient the Moon?
Authors: Mark A. Wieczorek  and Mathieu Le Feuvre

The Moon is currently locked in a spin-orbit resonance of synchronous rotation, of which one consequence is that more impacts should occur near the Moon's apex of motion (0° N, 90° W) than near its antapex of motion (0° N, 90° E). Several of the largest lunar impact basins could have temporarily unlocked the Moon from synchronous rotation, and after the re-establishment of this state the Moon would have been left in either its initial orientation, or one that was rotated 180° about its spin axis. We show that there is less than a 2% probability that the oldest lunar impact basins are randomly distributed across the lunar surface. Furthermore, these basins are preferentially located near the Moon's antapex of motion, and this configuration has less than a 0.3% probability of occurring by chance. We postulate that the current "near side" of the Moon was in fact its "far side" when the oldest basins formed. One basin with the required size and temporal characteristics to account for a 180° reorientation is the Smythii basin.

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Blobrana


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The far side of the moon could have been visible from earth billions of years ago, a new study suggests.
The relative rotations of the moon and the earth mean that only the one side is ever visible.
However, scientists believe that the impact of a large asteroid hitting the moon could have flipped it around, turning a different side that we now see towards earth.
A study of craters on the far side of the moon suggests that it was hit by a large object around 3.9 billion years ago.

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The lasting impression left by the Apollo missions is of a Moon that is grey, dusty, desolate and dead. But instruments left behind by Apollo astronauts recorded moonquakes and wobbles in its rotation that gave hints of a still molten core.
Now, a rock collected more than 36 years ago during Apollo 17, the last human visit to the Moon, reveals that the molten core may have once churned and generated a magnetic field.

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Blobrana


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Early Lunar Magnetism
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Title: Early Lunar Magnetism
Authors: Ian Garrick-Bethell, Benjamin P. Weiss, David L. Shuster, Jennifer Buz

It is uncertain whether the Moon ever formed a metallic core or generated a core dynamo. The lunar crust and returned samples are magnetised, but the source of this magnetisation could be meteoroid impacts rather than a dynamo. Here, we report magnetic measurements and 40Ar/39Ar thermochronological calculations for the oldest known unshocked lunar rock, troctolite 76535. These data imply that there was a long-lived field on the Moon of at least 1 microtesla ~4.2 billion years ago. The early age, substantial intensity, and long lifetime of this field support the hypothesis of an ancient lunar core dynamo.

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Blobrana


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Using a NASA radar flying aboard India's Chandrayaan-1 spacecraft, scientists are getting their first look inside the moon's coldest, darkest craters.
The Mini-SAR instrument, a lightweight, synthetic aperture radar, has passed its initial in-flight tests and sent back its first data. The images show the floors of permanently-shadowed polar craters on the moon that aren't visible from Earth. Scientists are using the instrument to map and search the insides of the craters for water ice.

"The only way to explore such areas is to use an orbital imaging radar such as Mini-SAR. This is an exciting first step for the team which has worked diligently for more than three years to get to this point" - Benjamin Bussey, deputy principal investigator for Mini-SAR, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

The images, taken on Nov. 17, 2008, cover part of the Haworth crater at the moon's south pole and the western rim of Seares crater, an impact feature near the north pole. Bright areas in each image represent either surface roughness or slopes pointing toward the spacecraft. Further data collection by Mini-SAR and analysis will help scientists to determine if buried ice deposits exist in the permanently shadowed craters near the moon's poles.

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Blobrana


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Ancient Moon Had Earth-like Core?
The mystery of the moon's magnetic field may finally be explained by the presence of an Earth-like core, a new study says.
Magnetic moon rocks picked up on the Apollo missions in the late 1960s and early 1970s surprised scientists, who thought no such field existed on the moon.

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Ancient rock's magnetic field shows that moon once had a dynamo in its core
The collection of rocks that the Apollo astronauts brought back from the moon carried with it a riddle that has puzzled scientists since the early 1970s: What produced the magnetization found in many of those rocks?
The longstanding puzzle has now been solved by researchers at MIT, who carried out the most detailed analysis ever of the oldest pristine rock from the Apollo collection. Magnetic traces recorded in the rock provide strong evidence that 4.2 billion years ago the moon had a liquid core with a dynamo, like Earth's core today, that produced a strong magnetic field.

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Blobrana


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The magic of the Moon has once again captured the imagination of politicians and scientists around the world.
Forty years ago, the largest TV audience in history tuned in to watch the Apollo 8 crew reach lunar orbit.
It was during this mission that the famous "Earthrise" image was captured, changing forever our perception of the planet and its place in space.
And in July 1969, a small step by Neil Armstrong during the Apollo 11 mission guaranteed his place in human history as the first person to set foot on another world.

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Lunar Ice
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Ice on the moon is most likely to be found in shaded polar craters, UK scientists have concluded.
Researchers from Glasgow and Durham universities analysed data from Nasa's 1998 lunar prospector probe to pinpoint likely locations.
They found that polar craters, which are shaded from the sun, could have ice in concentrations of up to 10 grams per kilo of rock.
Their findings are published in the scientific journal Icarus.

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Blobrana


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Científicos españoles participan en la creación de un nuevo modelo que explica los movimientos de la Luna
Dos investigadores de las universidades de Valladolid y Alicante están desarrollando una formulación matemática para estudiar la rotación de la Luna, considerando que su estructura está formada por una capa externa sólida y otra fluida en el interior. La propuesta forma parte de un estudio internacional que plantea un modelo teórico mejorado sobre la dinámica orbital y rotacional de la Tierra y su satélite, y con el que la comunidad científica podrá obtener mediciones más precisas para asegurar las futuras misiones de la NASA a la Luna.

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