Monday, February 23, 2009

'Lagrangian points' may solve 'most perplexing' moon mystery

Why does the Earth have such a large moon? It's one of "the most perplexing mysteries of the solar system," says New Scientist. In fact, the size of the Moon says Earth should have been destroyed billions of years ago.

Huh? Well, astronomers believe our moon is actually the leftovers of a cataclysmic collision between the earth and a Mars-sized planetoid. But the force of such a collision should have completely destroyed both objects. That is, unless the Mars-sized object developed right next to Earth (our evil little brother), before Venus (the evil older brother) quietly nudged it into us.

Such a massive object could have formed in one of Earth's five "Lagrangian points." There are points around massive objects in space where gravity is canceled out. Jupiter has one where hundreds of asteroids are stuck. And recently, we detected asteroids in Neptune's Lagrangian points, too. Now, a pair of satellites (NASA's STEREO twin-probes) are headed toward's a couple of Earth's biggest Lagrangians to see what's there. They may discover evidence that puts the mystery of our moon's size to rest.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.