Have you ever been to the Arctic?

If you're ever there, be sure to look up at the sky at night. You might see some really cool, luminescent clouds high up in the atmosphere. Scientists call them night shining clouds.

What makes them shine has been a mystery for a long time. However, a team of researchers is studying the life cycle of the clouds in the Arctic and Antarctica. One thing they know is that over the past few decades night shining clouds have become brighter, and are appearing at lower latitudes.

The researchers suspect it may have to do with global warming. See, the clouds form in the upper reaches of the atmosphere, where it's very cold. The colder it gets, the more clouds there are.

Confused with how these cold clouds are the result of global warming?

Well, global warming occurs when a thick layer of carbon dioxide builds up in the atmosphere, trapping heat near the earth's surface. However, all that heat trapped below makes things colder in the very upper parts of the atmosphere, where the layer of CO is very thin.

If there are more night shining clouds in the sky, and they're getting brighter, that could be one more sign of how global warming affects the atmosphere.

The more research they do, the more scientists will be able to tell us about how the clouds form, and what makes them shine.