Katherine Choi

Year: 2015-16


Target: Rhea and Tethys

"The solar system contains many unique objects that scientists would be able to learn a great deal of practical knowledge from. Not only would further analysis of the solar system bring the potential for a better understanding of our own planet, it also could lead to the discovery of extraterrestrial life. Rhea and Tethys are two of Saturn's moons that would be the most beneficial to study compared to all other targets for the Cassini Project.


Rhea is the second largest moon of Saturn and has a high reflectivity suggesting a composition largely of water ice, which actually behaves like rock in Rhea's temperature range. Unfortunately, these are some of the only things we know about Rhea and studying it would allow us to learn more. One example which demonstrates how much we do not know about Rhea is its potential ring system, which may or may not exist. This is because the first time we observed Rhea, scientists found some evidence of a ring system but during the second time we could not find that same evidence again. Learning more about Rhea and determining whether it truly has a ring system would be important for scientists since we do not know of any other moons which potentially has rings. On top of this, there is a possibility that it may contain an internal ocean. This, aided by the presence of an oxygen and carbon dioxide atmosphere, brings the potential for the moon containing extraterrestrial life. These interesting unsolved questions make Rhea an ideal candidate to further analyze more with the Cassini satellite.

Tethys is a moon that has many characteristics which makes it a good target for the Cassini Project. Orbiting 183,100 miles from Saturn, it is the third largest one of its moons and happens to be almost fully covered in ice. This indicates that it is possible that Tethys might have had liquid water in the past, which allows the slight chance that there may have been life there. On top of this, by studying more about the water on Tethys we can actually learn more about the particular properties of water and how it interacts in different places other than Earth. This would be a fascinating place for scientists to explore, in addition to the shiny surface of the moon which comes from the ice there. By researching Tethys, scientists will learn more about this moon and more about the nature of water on Earth.

The opportunity to study Rhea and Tethys gives scientists the opportunity to solve many unanswered questions about them and better understand their unique characteristics. Rhea is interesting because of how many conflicting observations we have so far and the large presence of water ice on Tethys brings the opportunity to learn more about how it has evolved over time. Tethys and Rhea are undoubtedly the best targets for scientists to study through the Cassini project since they will aid scientists most in their quest to learn more about the universe."

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