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Moon and Venus

January 21, 2015

One of the most spectacular sights in the night sky is an aurora — a shimmering curtain of light. It’s produced by the interaction between Earth’s magnetic field and the solar wind — a stream of charged particles from the Sun. The magnetic field funnels the particles toward the surface, where they hit atoms and molecules, making them glow.

Aurorae have been seen on other worlds as well. And they may have been seen on one where they weren’t expected: Venus.

Unlike Earth and the other worlds with confirmed aurorae, Venus doesn’t generate a magnetic field. No magnetic field, no aurora.

But observations by a telescope in New Mexico, and a spacecraft in orbit around Venus, suggest otherwise. The ground-based telescope has seen a green glow on Venus’s nightside. And the spacecraft detected energy at similar wavelengths.

Researchers at New Mexico State say the glow is most likely an aurora caused by solar wind particles hitting oxygen atoms about 75 miles above the surface.

The glow may require a perfect set of conditions: the unique chemistry of Venus’s atmosphere combined with a big outburst of particles from the Sun. The particles flow around Venus, forming a turbulent patch behind the planet. Particles in this patch are forced down into the atmosphere — where they just might create a bright glow high above the planet.

And Venus shines brightly as the “evening star” right now. Tonight, it stands just to the left of the crescent Moon.


Script by Damond Benningfield, Copyright 2014

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