Moon and Jupiter

StarDate: March 21, 2009

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Early risers are in for a nice treat the next couple of mornings -- a conjunction between the crescent Moon and the planet Jupiter. They're quite low in the east about an hour before sunrise. Tomorrow, Jupiter's to the lower left of the Moon.

Jupiter is the largest planet in the solar system. And despite centuries of study, in some ways it's still a giant mystery.

Jupiter probably consists of a small, dense core that's several times as massive as Earth. Layers of hydrogen and helium surround the core. They're squeezed so tightly that they form a metal. As Jupiter rotates, the core and the surrounding layers spin at different speeds. That generates a powerful magnetic field around the planet.

Yet the details are unclear. Scientists want to know how big the core is and what it's made of. They want to know more about the deep layers of hydrogen and helium and how they interact with the core to produce a magnetic field.

Scientists also want to know more about Jupiter's composition -- in particular how much oxygen it contains. That value will help answer some questions about how the planet formed -- and about the birth of the solar system's other planets, too.

NASA hopes to answer those questions with a new mission to Jupiter, called Juno. When it arrives in 2016, it'll map the planet's gravity and magnetic field, and peer far below its cloud tops. Juno will help scientists answer some of the questions about this solar system giant.

Script by Damond Benningfield, Copyright 2009

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