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Moon and Jupiter

May 14, 2016

[SFX: Voyager radio waves]

In March of 1979, Voyager 1 was cruising toward Jupiter, the solar system’s largest planet, when it ran into what sounds like a hurricane. That “roar” is caused by the interaction between Jupiter’s magnetic field and the solar wind — a “breeze” of charged particles from the Sun’s outer atmosphere.

Motions deep within Jupiter’s core produce a “dynamo” effect, which generates a powerful magnetic field. The field encases Jupiter in a sort of magnetic bubble, which is sculpted in part by a doughnut-shaped ring of gas around Jupiter.

The bubble extends a few million miles in toward the Sun, and hundreds of millions of miles away from the Sun. It’s so big that if it were visible to the human eye, it would be about five times bigger than the Moon.

Particles in the solar wind form waves in front of the bubble, like the waves that pile up in front of a ship as it moves across the ocean. The region where the waves form is known as the bow shock. It causes the solar wind to slow down and get hotter as it flows around Jupiter’s magnetic field — a protective bubble around a giant planet.

And Jupiter is in great view tonight. The giant planet looks like a brilliant star close to the upper left of the Moon at nightfall. It’ll stand even closer above the Moon as they set in the wee hours of tomorrow morning.

We’ll have more about Jupiter and the Moon tomorrow.


Script by Damond Benningfield

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