Saturn is almost 10 times farther from the Sun than Earth is. At that distance, the Sun looks only about one percent as bright as it does from Earth, so

Saturn is cold and dark. But it’s not quite as cold as you might expect. Saturn actually puts out more than twice as much energy as it receives – heat radiating from deep inside the planet.

Saturn is made mostly of hydrogen and helium – the lightest and simplest chemical elements. But its core contains a lot of rock, metal, and other heavy materials – more than 15 times the total mass of Earth. Gravity squeezes the core tightly, causing it to shrink. That produces heat, which rises to the surface and shines out into space.

But that doesn’t explain all of Saturn’s heat. The rest may come from an odd type of rainfall. Droplets of liquid helium may fall toward the core. As they fall, they produce friction, which produces heat.

Saturn’s internal heat drives much of the weather in its atmosphere, including storms that can be as big as continents – swirling clouds on a cold, dark planet.

Despite the lack of sunlight, Saturn looks bright in our sky because it’s huge – about nine times the diameter of Earth. It’s easy to see how bright the next couple of early mornings because it’s close to the Moon. Tomorrow, it’s to the lower left of the Moon at dawn. It’ll be a little farther to the right of the Moon on Wednesday.

Script by Damond Benningfield