A Moment of Science

Venus Glows In The Dark!

Venus may appear to glow under moonlight but the planet also glows in infrared light.

A telescope set up outside

Photo: Ryan Wick (Flickr)

Because Venus glows in infrared light, you cannot see it glow using a telescope.

Did you know that Venus glows in the dark? It is a different kind of glow that you see in the night sky. That type of glow is produced by earth’s atmosphere.

What Makes Venus Glow?

When the sun’s ultraviolet light hits Venus’ atmosphere, it breaks up large molecules into fragments. As those atoms recombine later, some of their energy is released as light. If they recombine on Venus’ night side in large enough amounts, the glow can be detected.

So far, scientists have found nitric oxide, oxygen, and hydroxyl radicals glowing at altitudes between 55 and 75 miles.

Can You See It Glow?

So, if I had a big telescope and looked at Venus’ dark side, I’d be able to see it glowing? Actually, no. The glow is in the infrared, a part of the light spectrum human eyes can’t see.

But we’re lucky that we have Venus Express, a European spacecraft with VIRTIS, out there watching. VIRTIS stands for Visible and Infrared Thermal Imaging Spectrophotometer. It can see infrared.

Studying The Data

Scientists are using the data to learn about the temperature, the wind direction, and the composition of Venus’ atmosphere. But they don’t understand everything.

Sometimes different molecules glow simultaneously, other times separately. They haven’t figured out why the glows happen when they do.

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