Author: Fraser Cain

Like Earth, Saturn’s axis is tilted relative to the Sun’s equator – 27-degrees on Saturn, compared to 23-degrees for Earth. And this tilt is very easy to see, because Saturn’s rings extend out from its equator. There are times during its orbit when we see Saturn’s rings fully extended, and other times when the rings are just a thin line, seen edge on.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

Since Saturn takes 30 years to orbit the Sun, so it’s seasons are much, much longer than Earth’s. Each of the planet’s hemispheres take turns soaking up radiation from the Sun, heating up. When the rings are fully facing the Sun, they can shade the planet, and further decrease the amount of energy received by the hemisphere experiencing winter.

And these seasons do have an impact on the planet’s weather. Over the course of 20 years, scientists recorded that wind speeds around Saturn’s equatorial regions decreased by about 40%. NASA’s Voyager flybys in 1980-81 detected wind speeds of 1,700 km/h, while they were only going about 1,000 km/h in 2003.

Here’s an article from Universe Today about how Saturn’s weather changes over long periods, and the discovery of a cyclone at the planet’s north pole.

Astronomy Picture of the Day has a beautiful image of Saturn’s changing seasons, and an article from BBC about the planet’s changing wind speeds.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

It’s almost impossible to say what is the temperature of Saturn. The highest cloud tops, right at the edge of space, are colder than -150 °C. But as you travel down into the planet, pressures and temperatures rise. At the very core, temperatures can reach 11,700 °C.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

As I mentioned above, the internal core of Saturn gets as high as 11,700 °C. This comes from the huge amount of hydrogen and helium compressing down and heating up the core.

Saturn actually generates heat. In fact, it’s putting out 2.5 times as much energy as it receives from the Sun. This is because the planet’s gravity is slowly compressing it down, and generating heat as it does this.

Once you reach the cloud layers in Saturn’s atmosphere, temperatures drop quickly. The bottom of the clouds are made of water ice and have an average temperature of -23 °C. Above this is a layer of ammonium hydrosulfide ice, with an average temperature of -93 °C. Above this are the ammonia ice clouds that give Saturn its orange/yellow color. Temperatures at the very edge of Saturn can get as low as -150 °C.

Here’s an article about a hot spot on Saturn, and the temperature of its rings.

Here’s an article about Saturn from How Stuff Works, and more facts on Saturn from ESA.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

Even through a small telescope, Saturn takes on a beautiful pale yellow with hints of orange. With a more powerful telescope, like Hubble, or images captured by NASA’s Cassini spacecraft, you can see subtle cloud layers, swirling storms mixing orange and white together.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

But what gives Saturn its color?

Like Jupiter, Saturn is made almost entirely of hydrogen, a small amount of helium, and then trace amounts of other compounds, like ammonia, water vapor and hydrocarbons.

The colors we see come just from the upper cloud layers of Saturn, which are largely composed of ammonia crystals, and the lower level clouds are either ammonium hydrosulfide or water.

Saturn has a banded pattern in its atmosphere, similar to Jupiter, but they’re much fainter and wider near the equator. It also has long-lived storms – nothing like Jupiter’s Great Red Spot – which often occur when the planet nears the summer solstice for the northern hemisphere.

Some photographs of Saturn captured by NASA’s Cassini spacecraft make the planet look blue, similar to Uranus. But this is probably just because of how the light is scattering from Cassini’s perspective.

This article has a nice full-color image of Saturn, and another nice wallpaper of Saturn.

Here’s a beautiful image of Saturn from Solar Views, and a false color image from Hubble.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.

Saturn has the lowest density of all the planets in the Solar System. The actual number is 0.687 grams per cubic centimeter. This is actually less dense than water; if you had a large enough pool of water, Saturn would float.

You can also check out these cool telescopes that will help you see the beauty of planet Saturn.

Just for comparison, Jupiter has an average density of 1.33 grams per cubic centimeter. So it wouldn’t float on water. And Earth, the densest planet in the Solar System, measures 5.51 grams/cubic centimeter.

If you’d like to calculate the density of Saturn for yourself, grab a calculator, and then divide the mass of Saturn (5.6846×10²⁶ kg) by its volume (8.2713×10¹⁴ cubic kilometers. This gives you a final number of 0.687 g/cubic centimeter.

Here’s an article about a fluffy extrasolar planet, even less dense than Saturn, and more information about the density of Jupiter.

Here’s a textbook that helps you make the density calculations for yourself, and more information here.

We have recorded two episodes of Astronomy Cast just about Saturn. The first is Episode 59: Saturn, and the second is Episode 61: Saturn’s Moons.