If you live near, or have ever been to, a very far northern or southern region, you might have noticed a rainbow shimmering in the sky around twilight. It's not the Northern (or Southern) Lights, it's a rare cloud phenomenon that looks beautiful, but hides a dangerous secret.
If you've ever seen a thin, streaky, rainbow-hued cloud high up in the sky, you're probably seeing a polar stratospheric cloud, also called a PCS or a nacreous cloud. These clouds form near the Earth's poles very high up in the atmosphere and make the sky blaze with rainbow colors, which can be very bright or more pastel.
The rainbow colors appear because these high, thin clouds are made of ice crystals, which scatter light waves and make us see colors down on Earth. For many, they're a fascinating sight to see at sunset, just like the beautiful but very simply explained columns of light that appear during winter nights.
But these clouds are a little more sinister.
Due to their position and makeup, they've been linked to ozone depletion. Because they're naturally occurring, there's not much we can do about them, but we can slow the depletion by making smart choices down on the ground.
In the meantime, we can enjoy their strange, colorful beauty. And they remind us that even though nature is beautiful, it sometimes has a destructive side!
[H/T: Amusing Planet]
Polar stratospheric clouds appear in the sky by the Earth's poles during the winter, and are most visible during twilight.
They look like streaks of rainbow color in the sky, and form high, high up in the stratosphere.
They're also called PSC's for short, or nacreous clouds. "Nacreous" refers to mother of pearl, and it's true they do look like the iridescent shells.
The ice crystals that form them scatter the sunlight, making them appear in all kinds of colors, like pinks, purples, greens, and oranges. It's really amazing!
Sometimes the colors are more subtle…
…and sometimes they're quite bright.
And sometimes these clouds cover much of the sky, creating a very surreal scene. It's like the sky has been tie-dyed.
Other times, they only appear as small areas, and can even be easy to miss if you're not looking out.
And sometimes they're very faint.
But they're all hiding a destructive secret.
The clouds, which are completely naturally occurring, actually play a role in the depletion of the ozone layer, which protects the Earth from the sun's harmful radiation.
It's because they cause chemical reactions that produce chlorine, and also remove nitric acid gas. Both of these things damage the ozone layer.
But since they're naturally occurring (and some 82,000 feet in the air), there's not much we can do about that.
To keep the ozone layer safe, it's best to make sure we use safe products and act responsibly down on the ground.
And even though they might be up to no good, we can still enjoy their unique beauty. They just prove what a complex, magical, and strange place our planet really is.
Please SHARE this phenomenon with anyone who loves strange things and loves to scan the heavens!
