Mission to Saturn Will Reveal Rich Information About the Ringed Planet, Trinity Scientist Says

by Susie P. Gonzalez

Additional Resources: NASA- Jet Propulsion Labratories Cassini-Huygens Website

June 25, 2004 – The end of June and beginning of July will mark a historic time in the quest for outer planetary information. That’s when the Cassini spacecraft, which was launched in 1997, will arrive at Saturn, the most easily recognizable plant in the solar system because of its highly visible ring system.

After its long journey, the Cassini craft is expected to reveal a wealth of new scientific information about Saturn’s rings and its multiple moons. Mark C. Lewis, assistant professor of computer science at Trinity and a student of Saturn’s rings since the 1990s, said data about Saturn has been limited for decades to flyby missions such as the Pioneer or Voyager, when photographs were taken as the craft was streaking by.

With the Cassini mission, Professor Lewis says, “We will get a completely new vision of the Saturnian system, one with much more depth and detail.” A graduate of Trinity in 1996 with degrees in physics and computer science, Professor Lewis went on to earn a doctorate in astrophysics and planetary science from the University of Colorado at Boulder. With regard to Saturn, his research interest lies in computer simulations of planetary rings.

“While all of the giant planets have rings, the ones at Saturn are by far the most impressive and they contain a variety of distinct subsystems,” Professor Lewis says. “Some parts of the ring are optically thick while others are optically thin and largely transparent.” In addition, he notes that some parts of the ring system interact in different ways with various moons. In some cases, the moons actually are buried in the rings and pull on the ring particles as they orbit the planet.

In addition to learning more about the planet’s rings, the mission will shed new light on Saturn’s moons. An onboard probe named Huygens will focus on the largest moon, Titan. Professor Lewis says the probe is the size of a school bus and contains a large array of scientific instruments to measure and photograph all aspects of the Saturn, its moons, and its rings.

Why spend seven years traveling to such a distant planet? Professor Lewis says the reasons are numerous. “We have a fundamental interest in the planet itself and what we can learn about its inner workings from the cloudy layers visible on the surface. We have an interest in Titan because it is a very odd moon in many ways. Titan is the only moon in our solar system with a thick atmosphere. Not only does it have a thick atmosphere, but its composition is very similar to what scientists think the early Earth atmosphere was like.” However, Titan’s atmosphere has been in a state of deep freeze, which has slowed chemical reactions and kept it in a state similar to the time of formation, he says.

Professor Lewis said scientists have an interest in understanding the dynamics of the rings because they resemble disks in our solar system and others that formed around young stars. “In addition, Cassini is likely to teach us things that we didn’t even realize we didn’t know,” he says, adding that Cassini will transmit as much information back to Earth in a week as a Voyager probe would in its full flyby mission. “The amount of information we get will be unprecedented in the exploration of the outer solar system.”

Erika Barth, who graduated from Trinity in 1998 and received a doctorate in May from the University of Colorado at Boulder, has been studying Titan’s atmosphere by developing models of the moon’s cloud formations. The Cassini mission will enable astronomers to look through the haze surrounding Titan and learn more about its surface composition, she says. Based on the Voyager’s findings, scientists have thought the large moon is covered with ice amid layers of methane and ethane gases. But Dr. Barth is hopeful that the mission will prove or debunk this theory in her current work with planetary science in the Boulder branch of Southwest Research Institute.

© 2006 Trinity University