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Moon and Jupiter

March 9, 2014

Two of the three brightest objects in the night sky huddle close together the next couple of nights. As darkness falls this evening, Jupiter — the third-brightest object — stands close to the upper left of the brightest: the Moon.

Although Jupiter looks like a brilliant star, it’s not — it’s the biggest planet in the solar system — big enough to hold about a thousand Earths. It grew so big in a couple of ways.

First, it’s thought to have a dense core of rock and metal that’s several times as massive as Earth. This core formed in a region of the young solar system where there were more of the ingredients for making planets. Where Earth formed, heat and radiation from the Sun vaporized some of the planet-making materials and swept them away.

And second, the gravity of Jupiter’s newly formed core easily grabbed vast amounts of hydrogen and helium that were left over from the birth of the Sun — gases that were also pushed out of the inner solar system by the newborn Sun. They account for the vast majority of Jupiter’s mass and size. In fact, they make it not only the biggest planet in the solar system, but also the heaviest — heavier than all of the other planets and moons combined.

Look for mighty Jupiter to the upper left of the Moon in early evening, and creeping even closer to it during the night. Jupiter will be a little farther to the upper right of the Moon tomorrow night.

Script by Damond Benningfield, Copyright 2014

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