Cassini Scientist for a Day -- Spring 2009 Winners, Target 3: Epimetheus and Janus, Grade 9 to 12
|Congratulations Cassini Scientist for a Day Winners |
Target 3: Epimetheus and Janus
|Grade 9 to 12
Seminole Ridge Community High School
"The Cassini spacecraft should photograph Epimetheus and Janus, moons of Saturn which share almost exactly the same orbit but have managed to avoid colliding for billions of years now, because they have much to tell us about the physics and history of our solar system.
Primarily, both moons are heavily cratered and so they would serve as an excellent record of major activity near Saturn. I am not suggesting that some unusual activity has occurred to crater these moons more heavily, but rather that because their surfaces are heavily cratered, it would be logical to assume that they are very old. The rule of thumb is the rate of cratering remains constant, so the more craters, the older the surface. Thus using these moons as a geological record we could find evidence of the event that caused both moons to share the same orbit hidden in the geological features of both moons, and getting just a little bit closer with Cassini would allow us more detailed images to help solve this mystery.
We need to get close enough to the moons to look for sharp edges on both moons. Previous images taken show us that Janus is larger, and this presents evidence toward the theory that both moons started as one body and a smaller chunk was ripped off by some celestial event. And possibly, these edges will show the two moons fitting together like puzzle pieces (similar to supercontinent Pangaea). This would mean that they came from the same object. If we were able to find what caused the original object to split, we could use this information to find similar cases to that of the satellites.
Most importantly, by using Cassini to study Epimetheus and Janus we could get a look at the movements of these moons. This could lead to a greater understanding of the forces that cause these two celestial bodies to switch orbit on a seemingly regular interval and possibly use this application of physics to manipulate smaller celestial bodies, such as if we discovered an asteroid headed toward us. We could also make better sense of the theory that currently explains why the two moons switch orbits every four years, which is that because each moon has a different velocity the inner will catch up to the outer and the gravitational attraction boosts the inner moons orbit, causing it to decelerate, at the same time the outer moon loses momentum and slows to the lower orbit. We should study to see if they switch like a double pendulum swinging.In closing, the Cassini spacecraft should image Epimetheus and Janus, because observing these two bodies would show the most benefit toward us. Doing so would allow us to take a glimpse back in geological history to see just exactly what caused these two moons to share the same orbit around Saturn. If we were to get closeup photographs of Epimetheus and Janus, we would certainly gain clearer insight into the physical forces governing their movements."