Grail orbiters to arrive at Moon this weekend to study gravity

On Dec 31 2011, 3:04*am, Belba Grubb II wrote:
"...Why the moon is ever so slightly lopsided with the far side more
mountainous than the side that always faces Earth remains a mystery. A
theory put forth earlier this year suggested that Earth once had two
moons that collided early in the solar system's history, producing the
hummocky region.

Alternate explanation is that tidal lock occured while the Moon was
partly submerged under a global ocean, just like the current Earth.
While iron and magnesium silicates precipitate readily as olivine
(basalt), aluminum silicate (clay) does not precipitate but forms a
colloidal suspension with a negative charge.
Al(+3) + SiO4(-4) -AlSiO4(-1).
Despite attempts by sodium and potassium to neutralize the
molecule, clay remains in suspension and is propelled towards
the shore by the waves. Thus the mountains of the far side are
the result of massive accumulation of clay.
Under lunar conditions, potassium and sodium escaped into lunar
atmosphere and were replaced by calcium, thus forming anorthite
Ca(AlSiO4)2, the principal component of the rocks of the far side.
John Curtis

"Grail is expected to help researchers better understand why the moon
is asymmetrical and how it formed by mapping the uneven lunar gravity
field that will indicate what's below the surface.

"'It seems that the answer is not on the surface,' said chief
scientist Maria Zuber of the Massachusetts Institute of Technology.
"We think that the answer is locked in the interior."

"Previous lunar missions have attempted to study the moon's gravity—
which is about one-sixth Earth's pull—with mixed results. Grail is the
first mission devoted to this goal.

"Once in orbit, the near-identical spacecraft will spend the next two
months refining their positions until they are just 34 miles above the
surface and flying in formation. Data collection will begin in
March...."

*-- Full story, "Moon countdown..." at

http://www.breitbart.com/article.php...show_article=1

Barb
-------------

And from my pillow, looking forth by light
Of moon or favouring stars, I could behold
The antechapel where the statue stood
Of Newton with his prism and silent face,
The marble index of a mind for ever
Voyaging through strange seas of Thought, alone.

* -- William Wordsworth in "The Prelude"

The $496 million mission will be closely watched by schoolchildren. An
effort by Sally Ride, the first American woman in space, will allow
middle school students to use cameras aboard the probes to zoom in and
pick out their favorite lunar spots to photograph.