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A pair of twin spacecraft from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission have completed a new map showing the Moon's gravity in unprecedented details. The new map is now the most detailed map of the gravity of any celestial body. The new data could help scientists understand how the Earth and other planets form. If we're lucky, it could also lead to revolutionary new moon bounces at parties, or at least safer moon bounces. Okay, maybe not, but it's still neat.

Earlier this morning, NASA launched the spacecraft that will be under taking the Gravity Recovery and Interior Laboratory (GRAIL) mission, which aims to shine some light on the moon's internal structure, history and evolution. The two spacecraft, GRAIL-A and GRAIL-B, launched together this morning, strapped to a Delta II rocket and are slated to reach the moon on New Years Eve 2011 and New Years Day 2012 respectively. One there, they'll fly around the moon in formation, measuring changes in gravity and using the data to infer all kinds of things about the Moon's core and history. In addition to all that gravity stuff, the GRAIL spacecraft are also equipped with cameras devoted to the MoonKAM project (a pained acronym for Moon Knowledge Acquired by Middle school students) that will let middle school classrooms request picture of specific parts of the moon. In addition to acquiring moon knowledge, these lucky kids will get to experience the concentrated joy of interacting with and having an effect on an actual spacecraft that is in space. I'm pretty jealous. (via NASA, GRAIL MoonKAM)

Following one year of gravitational data collection, the European Space Agency's GOCE satellite has produced what the ESA says is the most accurate model of the Earth's geoid ever produced. A geoid is, essentially, a surface that describes the way the Earth's oceans would shake out if there were no tides or currents and if the oceans could travel over continents: If gravity was all that mattered. (Wikipedia has a more rigorous definition.) As you can see in the animation above (h/t Bad Astronomy), it is quite a lumpy fellow. ESA:

[The geoid] is a crucial reference for measuring ocean circulation, sea-level change and ice dynamics – all affected by climate change. ... A precise model of Earth's geoid is crucial for deriving accurate measurements of ocean circulation, sea-level change and terrestrial ice dynamics. The geoid is also used as a reference surface from which to map the topographical features on the planet. In addition, a better understanding of variations in the gravity field will lead to a deeper understanding of Earth's interior, such as the physics and dynamics associated with volcanic activity and earthquakes.

(ESA, Bad Astronomy via Cindy Au)

This coffee cup stays balanced at a gravity-defying angle when it's resting on a flat surface with no fluid inside. You do have to set it down when it's filled up with coffee. Bonus: The 'trajectory of love' graph on the side.

New satellite imaging from the Gravity field and steady-state Ocean Circulation Explorer, GOCE for short, has given us a much more detailed picture of Earth's gravity field, and thus a more accurate knowledge of the planet's geoid. The geoid is basically a depiction of the planet devoid of land masses, where the planet is pure ocean, shaped by the gravitational field. It's pretty lumpy. After all, Earth is by no means a perfect ellipse, so the planet's gravitational field isn't either. The image below is representative of our current knowledge, and a much more detailed version will be able to be created from the GOCE's data. The image above was the result of only two months of gathering, so in a short time we will have an even more detailed sense of the Earth's gravitational field and be able to create an analglyph better than that below.