How Does Saturn's Atmosphere Affect the Planet?


I'm Eric Loberg director of the Taylor Planetarium at the Museum of the Rockies. I'm going to discuss how Saturn's atmosphere affects the planet. Which is kind of an interesting because most of Saturn's atmosphere is the planet. Saturn is a great big gas giant as are most of our outer planets so mostly it was gas that clumped around and as that gas starts to clump together it starts to form probably a rocky center in the middle but we're not quite sure so it's hard to say how the atmosphere affects that very center dense rock. Instead we can look at how the atmosphere around the planet affects the planet itself. We know that there's we think four bands, at least we know there's an outer band, that's the band we can see all the time of Saturn. It doesn't look at dark as Jupiter's because there's only trace elements. Saturn has a little bit different composition than some of the other planets. Saturn has quite a bit more helium. It doesn't add it up as much as weight. It's only a little bit of the weight of Saturn because Saturn is so light. Saturn is actually so light that if it was a marshmallow and you dropped it in a cup of cocoa it would float. And that's because there's so much helium in Saturn. It's lighter than the other planets, like Jupiter, Uranus and Neptune. It has a lot of hydrogen about 75 percent of hydrogen in Saturn but it has way more helium than those other planets. About 25 percent of the planet is helium and that really affects those cloud bases. The upper clouds go at about 1800 miles an hour wind speed. That is some of the highest winds you find in the solar system. It's about negative 250 degrees in these clouds, some ammonia up in the high cloud bubbles. It's hard to see underneath that, not nearly as much color as you'd get in the planets say like Jupiter. You see a lot of bands. The bands on Saturn look very, very white. Once in awhile you'll get cloud layers that erupt and these cloud layers will erupt from lower clouds. These lower clouds, we think there might be little drops of water in these clouds. Might get just warm enough that there's a little bit of trace elements in Saturn like ammonia, sulfur, oxygen, just enough oxygen you might get a little bit of liquid water up there in the cloud layers that might sustain things like giant storms. You have a giant wind storm in the northern hemisphere that's actually a very strange shape. It's shaped like a hexagon up in the northern hemisphere of Saturn. And it's been going there for at least 15 years. We saw it with the Voyagers we've seen it more recently with Casini, a weird odd shaped storm up in the cloud base. We're trying to figure out how to replicate that. It might be due to different liquids and it might because there's some liquid water in this lower cloud base that we can't see very often. Underneath that we just have to guess. There's probably hydrogen underneath that interior we have so much pressure it's starting to turn in to liquid and even farther down helium. Helium is even lighter than hydrogen so it will sink right through that hydrogen and collect at the bottom and you have helium down here in the middle of that planet and the planet has some sort of core that we think is rotating because it has a magnetic field just like Earth does and so with that metallic rotating core you get magnetic fields out of the north and south pole and so you'll get some aurora on Saturn and what you get the aurora from is both the magnetic pulses out of the planet itself, it has to interact with something, and so particles from its moons are coming out and interacting with Saturn, the planet itself and you get aurora at the north and south pole of Saturn due to the moons and due to the surface of Saturn. So how does the planet interact with the atmosphere. Well the atmosphere is most of the planet. The atmosphere starts out up high, it's pretty cold, it goes a little warmer down low but the pressure starts to increase and your gases start to turn in to liquid metals as you go farther and farther down. I'm Eric Loberg with the Taylor Planetarium at the Museum of the Rockies.

J. Eric Loberg is the manager, lecturer, and program planner at the Taylor Planetarium at the World, a renowned museum of the Rockies in Bozeman, Montana.