A daily miasma of frivolity by two wanna-be cultural critics. Or: just, like, some good links, dude.

Tag Archives: the Moon

Dec 29 2011
Mark Twain, probably

Grail spacecraft to study moon’s gravity field

Grail spacecraft to study moon’s gravity field

Alicia Chang, the AP:

Over the New Year’s weekend, a pair of spacecraft the size of washing machines are set to enter orbit around it in the latest lunar mission. Their job is to measure the uneven gravity field and determine what lies beneath – straight down to the core.

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Once in orbit, the spacecraft will spend the next two months flying in formation and chasing one another around the moon until they are about 35 miles above the surface with an average separation of 124 miles. Data collection won’t begin until March.

As the probes circle the moon, regional changes in the lunar gravity field will cause them to speed up or slow down. This in turn will change the distance between them. Radio signals transmitted by the spacecraft will measure the slight distance gaps, allowing researchers to map the underlying gravity field.

It’s not a manned mission, but hey, science still rules.

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Sep 15 2011
Mark Twain, probably

This is the sharpest image ever taken of the Apollo 12 landing site.

One of the details that shows up is a bright L-shape in the Apollo 12 image. It marks the locations of cables running from ALSEP’s central station to two of its instruments. Although the cables are much too small for direct viewing, they show up because they reflect light very well.

The higher resolution of these images is possible because of adjustments made to LRO’s [Lunar Reconnaissance Orbiter], which is slightly oval-shaped or elliptical. “Without changing the average altitude, we made the orbit more elliptical, so the lowest part of the orbit is on the sunlit side of the moon,” said Goddard’s John Keller, deputy LRO project scientist. “This put LRO in a perfect position to take these new pictures of the surface.”

The maneuver lowered LRO from its usual altitude of approximately 31 miles (50 kilometers) to an altitude that dipped as low as nearly 13 miles (21 kilometers) as it passed over the moon’s surface. The spacecraft has remained in this orbit for 28 days, long enough for the moon to completely rotate.

Check out NASA’s page for more, including photos of the Apollo 14 and 17 landing sites.

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Aug 04 2011
Mark Twain, probably

Early Earth may have had two moons

Early Earth may have had two moons

Richard Lovett for Nature:

Earth once had two moons, which merged in a slow-motion collision that took several hours to complete, researchers propose in Nature today.

Both satellites would have formed from debris that was ejected when a Mars-size protoplanet smacked into Earth late in its formation period. Whereas traditional theory states that the infant Moon rapidly swept up any rivals or gravitationally ejected them into interstellar space, the new theory suggests that one body survived, parked in a gravitationally stable point in the Earth–Moon system.

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The Moon’s visible side is dominated by low-lying lava plains, whereas its farside is composed of highlands. But the contrast is more than skin deep. The crust on the farside is 50 kilometres thicker than that on the nearside. The nearside is also richer in potassium (K), rare-earth elements (REE) and phosphorus (P) — components collectively known as KREEP. Crust-forming models show that these would have been concentrated in the last remnants of subsurface magma to crystallize as the Moon cooled.

What this suggests, [Erik] Asphaug says, is that something ‘squished’ the late-solidifying KREEP layer to one side of the Moon, well after the rest of the crust had solidified. An impact, he believes, is the most likely explanation.

Interesting new hypothesis by Erik Asphaug from UC Santa Cruz and Martin Jutzi of the University of Berne. It’s a neat idea, and it could be true, but we still don’t know enough about the formation of the Moon to know for sure. Hopefully we’ll learn more from future lunar missions.

Oh wait!

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