Category: Guide to Space

Just like Jupiter, Saturn radiates out more energy that it draws in from the Sun. In fact, Saturn radiates 2.3 times more energy than it receives from the Sun.

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

This has been a bit of a mystery to scientists. But the solution lies in the fact that Saturn’s atmosphere is relatively poor in helium, compared to Jupiter. Scientists think it cooled faster than Jupiter after initial formation, and then helium droplets formed when the temperature of the atmosphere dropped below 15 K. These droplets have been falling down into the core of Saturn, heating it up, and generating the heat.

When NASA’s Cassini first arrived at Saturn, the spacecraft detected lightning storms and radiation belts around the planet. It even found a brand new radiation belt located inside the rings of Saturn. The belts extend from about 139,000 km from Saturn’s center out to 362,000, and contain highly charged particles.

Here’s an article about Cassini finding the radiation belts around Saturn, and another about strange radio emissions coming from Saturn, related to the belts.

Here’s more information on the radiation belts, and a nice photograph from NASA.

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.

Jupiter is well known for the storms that rage across its upper atmosphere, especially the Great Red Spot. But Saturn has storms too. They’re not as large, intense or large lived, but compared to Earth, they’re enormous. And Saturn has one of the big mysteries in the Solar System; a hexagon-shaped storms at its poles.

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

Winds blow hard on Saturn. The highest velocities are near the equator, where easterly blowing winds can reach speeds of 1,800 km/h. The wind speeds drop off as you travel towards the poles.

Like Jupiter, storms can appear in the bands that circle the planet. One of the largest of these was the Great White Spot, observed by the Hubble Space Telescope in 1990. These storms seem to appear once every year on Saturn (once every 30 Earth years).

NASA’s Cassini spacecraft discovered static hexagonal storm circling around Saturn’s north pole, including a clearly defined eyewall – just like a hurricane. Each side on the northern polar hexagon is approximately 13,800 km long, and the whole structure rotates once every 10 hours and 39 minutes; the same as a day on Saturn.

Here’s an article about a time when Cassini tracked a long-lived lightning storm on Saturn, and another about the strange “Dragon Storm” seen in the planet’s southern hemisphere.

Here’s an article about the northern hexagonal storm from MSNBC, and Astronomy Picture of the Day has an image of storm alley on Saturn.

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 hard to imagine a planet less hospitable for life than Saturn. The planet is comprised almost entirely hydrogen and helium, with only trace amounts of water ice in its lower cloud deck. Temperatures at the top of the clouds can dip down to -150 C.

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

Temperatures do get warmer as you descend into Saturn’s atmosphere, but the pressures increase too. When temperatures are warm enough to have liquid water, the pressure of the atmosphere is the same as several kilometers beneath the ocean on Earth.

To find life, scientists will want to take a good look at Saturn’s moons. They’re comprised of significant amounts of water ice, and their gravitational interaction with Saturn probably keeps their interiors warm. Saturn’s moon Enceladus is known to have geysers of water erupting from its southern pole. It’s possible that it has vast reserves of superheated water beneath an ice crust.

And Saturn’s moon Titan has lakes and seas of hydrocarbons, thought to be the precursors of life. In fact, scientists think that Titan is very similar in composition to the Earth’s early history.

Hydrocarbons have even been detected across the surface of Saturn’s moon Hyperion.

There might not be life on Saturn, but there are enough intriguing locations to explore around the ringed planet to keep astronomers busy for years.

Here’s an article about exotic life that could live on Titan, and another that dismisses the possibility that there’s life on Enceladus.

This is an article from the Guardian about the possibility of life on Enceladus, and hydrocarbons on Hyperion.

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 formed with the rest of the planets 4.6 billion years ago, out of a spinning disk of gas and dust. This dust collapsed down to form the Sun, and planets formed out of the disk around it. This is why all of the planets orbit the Sun in the same direction.

That’s the easy question.

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

The more complicated question is, how old are Saturn’s rings? Some parts might be almost as old as the Solar System, but others are being continuously refreshed. The primary theory for the formation of Saturn’s Rings is that a 300 km moon was torn apart by Saturn’s gravity into the ring system that we see today. But that probably happened more than 4 billion years old.

But Saturn’s rings are bright, and almost made of pure water ice. Since infalling dust should have darkened the rings, they might be as young as 100 million years old. Or perhaps they are ancient, but regular collisions between ring objects keep them looking fresh and new.

One interesting note. Astronomers think that the composition of Saturn – 88% hydrogen and 11% helium with other trace elements – almost exactly matches the composition of the early solar nebula. Saturn is like a miniature version of the Solar System.

Here’s an article from Universe Today that discusses how Saturn’s rings could be as old as the Solar System, and another article about how gas giant planets might have consumed many of their moons early on in their history.

Ask an Astronomer has another answer to this question, and another look at the age of the rings from Geology.com.

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 is almost entirely hydrogen and helium, but it does have trace amounts of other chemicals, including water. When we look at Saturn, we’re actually seeing the upper cloud tops of Saturn’s atmosphere. These are made of frozen crystals of ammonia.

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

But beneath this upper cloud layer, astronomers think there’s a lower cloud deck made of ammonium hydrosulfide and water. There is water, but not very much.

Once you get away from Saturn itself, though, the nearby area has plenty of water. Saturn’s rings are almost entirely made of water ice, in chunks ranging in size from dust to house-sized boulders.

And all of Saturn’s moons have large quantities of water ice. For example, Saturn’s moon Enceladus is thought to have a mantle rich in water ice, surrounding a silicate core. Geysers of water vapor were detected by NASA’s Cassini spacecraft, spraying out of cracks at Enceladus’ southern pole.

If you want to look for water at Saturn, don’t look at the planet itself, but there’s water all around it.

Here’s an article from Universe Today about the plume of water ice coming off of Enceladus, and how Saturn’s environment is driven by ice.

Here’s an article from NASA about the composition of ice at Saturn’s moon Rhea, and the discovery of liquid water on Enceladus.

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.

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.