Why Is The Sky Blue?

Jun 24, 2016

Why is the sky blue? We get an answer from a science writer for NASA's Space Place. And what are Saturn's rings? Carolyn Porco of the Cassini Imaging Team explains.

"We see blue when we look up at the sky because of how the light from the sun interacts with our atmosphere. That's the layer of gasses that's above the earth.

"Sunlight is plain white light. White light is actually a mixture of all of the colors of the rainbow.

"Light is a form of energy. When a surge of energy passes through ocean water, you see that as a wave.

"Light energy travels in waves too, and that's important in understanding the color of light that we see.

"Long, lazy, low energy waves are seen as the color red. Short choppy high energy waves are seen as blue light.

"When sunlight reaches the earth's atmosphere, it hits the gases and other particles in the air and the light that is coming from the sun scatters.

"Why is the sky blue?" - Kabir, 6, Austin, TX
6-year-old Kabir lives in Austin, TX. He enjoys playing with cars and with his baby sister. When he grows up, he plans on becoming the president, an inventor and a soccer player, though not necessarily in that order.
Credit Photo Courtesy Kabir's mom

"The shorter smaller waves are scattered more strongly than the other waves. So it's the blue ones, the short choppy waves that are scattered the most strongly, more than any of the other colors. And that's why we see the blue light in the sky. "

— Jessica Stoller-Conrad, science writer for NASA's Space Place.

Click here to see an explanation with images.

"How do Saturn's rings stay on it and go really fast? And how do they spin around?" -Francisco, 4, Vergennes, VT

Francisco, 4, lives in Vergennes, VT. He's interested in space, volcanoes, dinosaurs, creating fairy houses, holding his little sister and exploring!
Credit Photo courtesy Francisco's mom.

"Saturn's rings do go really fast, but they don't spin around. They, in fact, consist of countless icy particles made of water ice that range in size from the tiniest particles you find in talcum powder all the way to the size of small apartment buildings.

Each of these particles is in separate individual orbit around Saturn. You can think of each of them as being a moon of Saturn. There are just lots and lots of them and they are all packed closely together and that's what Saturn's rings really are. They are a disk of debris, or a collisional product from a break  up of the moon or a body in orbit around Saturn that happened a very long time ago."

— Carolyn Porco, leader of the Cassini imagining team

Click here to see images of Saturn from Cassini.

Listen to the full episode for more.

Read the full transcript