Goal to get to know the moons of Saturn a bit better and to understand the atmosphere and surface of Titan Objectives: 1)To explore some of the moons of Saturn and their important features 2)To learn about Atmosphere of Titan 3)To explore the Surface of Titan courtesy of the Huygens probe.

Janus and Epimetheus These two moons (181 km and 116 km in size) share an orbit – sort of. They swap positions every 4 years. Janus is the innermost right now, but will swap again in While their orbital distance differ by only 50 km, they never get closer than km to each other.

Pandora/Prometheus – F ring

Some newer inner moons details.cfm?videoID=158

Run for your lives, it’s the Death Star! Phew, it is just Mimas. Very ice, very old surface. The Herschel crater is 140 km in diameter. Mimas is 400 km in diameter.

Enceladus Somehow the south pole has warmed and partially melted. Geysers have been created as a result, and the surface of Enceladus is being covered over by fresh snow. Enceladus has the most reflective surface in the solar system (reflects 90%), and would make the best place in the solar system to ski. Diameter = 500 km, and somehow the rotation of the moon is slowing (and it is flattening).

To scale

Enceladus – 40% closer to Saturn than our moon is to us

Ice volcanoes!

Why Enceladus, and not Mimas? You need a full tug of war, and Enceladus has a 2:1 orbital resonance with Dione. So, it gets just enough tidal heating for geologic activity at the south pole. Some ramifications… This means that Enceladus has some atmosphere!

Enceladus atmosphere! The atmosphere is mostly water vapor and if pretty thin. Like on Io, the atmosphere is localized, and not global. Being small, it cannot hold onto it, so it has to be replenish it (with the eruptions). This loss of water vapor is the source for the E ring!

3 miles wide!

Explore, hike, and/or ski the mountains and craters of Enceldus’s older side

Results

The E ring

Tethys 1000 km in diameter. Very icy, and very old. Lots of craters. Density close to water. Oddly, this moon has two small “trojan” moons which share its orbit (60 degrees in front and in back) – Calypso and Telesto

More batterings 4 large craters

The companions to Tethys Telesto - 24 kmCalypso - 22 km Young, +60 degrees 60 degrees behind

Dione 560km in diameter. About same distance from Saturn as our moon is from earth. Mostly old surface, but has strange cracks.

Tale of two sides

High res

Dione’s companions Helene (32 km) leading Polydeuces 3 km discovered 2004

Rhea

Skipping Titan for now, Hyperion 266 km in size. Largest irregular shaped moon in the solar system. Different color possibly from falling objects. Very sponge like and low density

Wierdest moon! Hyperion Very low density Means lots of holes When it gets hit ejecta escapes instead of falling into other craters. 280 km across In addition, the crater floors get a dark material that allows it to heat up and vaporize ices

Iapetus Very bizarre surface. Due to newly discovered ring created from Phoebe

Iapetus By Saturn shine. The star trails are due to orbiting and a 82 second exposure.

craters and 6 mile mountains

details.cfm?videoID=105

Phoebe Very battered. The outermost of the sizable moons of Saturn (200 km in diameter)

Titan! 1 of 2 moons with an atmosphere. Atmosphere is 40% higher pressure than Earths! Mostly Nitrogen The orange is a methane haze. HST image. To see the surface requires a probe!

Titan’s atmospheric profile

Huygens probe s/video-details.cfm?videoID=117http://saturn.jpl.nasa.gov/multimedia/video s/video-details.cfm?videoID=117 s/video-details.cfm?videoID=124

Further Fly Bys s/movies/PIA09183.movhttp://saturn.jpl.nasa.gov/multimedia/video s/movies/PIA09183.mov

Clouds – N. Pole

Jet stream!

Rivers ?

Xanadu

The “rocks” of Titan But not stone, frozen water. But at these temperatures, water is hard as rock. Surroundings is a watery, tarry version of sand.

Volcano ?

RAIN! In the mornings (which last 3 earth days out of its 16 earth day rotational period) you get a morning drizzle! The drizzle is of course METHANE! Where does this methane in the atmosphere come from though? Evaporation from lakes or from volcanoes? Only future probes will be able to find out.

Conclusion Most of Saturn’s moons have old, cratered, icy surfaces. Some moons are quite strange. Enceladus is creating a new ring! Titan has evidence for methane rivers and lakes and once maybe a methane ocean and needs to be studied a lot more.