Moon and Jupiter

StarDate: February 10, 2014

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Hydrogen is the simplest and most common chemical element — it makes up most of the “normal” matter in the universe. That might make it sound a bit ordinary. Yet it can do some extraordinary things. Chill it to just above absolute zero and it makes a powerful rocket fuel. Squeeze it tightly in the heart of a star and it makes the star shine.

And in the hearts of giant planets, hydrogen forms a metal. Currents within this dense liquid can generate magnetic fields that extend hundreds of millions of miles into space.

The best example of that is Jupiter, the largest planet in the solar system. It looks like a brilliant star a little to the upper left of the Moon as night falls this evening.

Hydrogen makes up about 70 percent of Jupiter’s mass. In the planet’s upper atmosphere, it combines with other elements to make water, ammonia, and other compounds.

As you move deeper, Jupiter’s gravity compresses the hydrogen to form a liquid. And as you move deeper still, the electrons and protons in the hydrogen atoms separate, producing a layer of metallic hydrogen that’s thousands of miles thick.

Jupiter’s fast rotation creates strong eddies and streamers within this layer, generating electrical currents. That creates a magnetic field that’s thousands of times stronger than Earth’s. Sculpted by the solar wind, it extends almost all the way out to the orbit of Saturn — an extraordinary structure created by the most ordinary of elements.

 

Script by Damond Benningfield, Copyright 2013

For more skywatching tips, astronomy news, and much more, read StarDate magazine.

The one constant in the Universe: StarDate magazine

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