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You're listening to Shortwave from NPR.

Hey, shortwaivers, I'm Mali Kwong here, and today we are headed north to Norway, the land of the midnight sun.

This guy looks like cotton candy the whole day, because you have a sunrise that doesn't stop.

It's just a full day of sunrise or a sunset.

Because Earth rotates on a tilt, there is a period of time during the summer where the North Pole always faces the sun and creating a polar day, or perpetual sunlight.

But in exchange, there's also a period of time during the winter of perpetual darkness.

That's called the polar night.

So the polar night is the period between the last sunset and fall

and the first sunset in spring,

during which the sun never rises in the Arctic for several months.

This is Clara Hopa. She's a biogeochemist at the Alfred Wegener Institute in Germany.

But a lot of her fieldwork is based here around the Arctic Circle.

During the polar night, she says, it's like everything is in gray scale.

When it's really dark, it's really a black and white world, I would say, where you see some gray shades of things.

And you see stars in the moon.

It's really quiet.

There's wind.

There's instrument noise.

There's, you know, ship sounds and snowmobiles.

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