Undergraduate Student Discovers How To Tell Time On Saturn
Time on Saturn has proved to be a fickle beast for scientists to pin down because of the thick layers of clouds and liquid gases rotate at their own speeds around the planet.
Decades ago, a strong and naturally occurring radio signal called the Saturn Kilometric Radiation (SKR) was thought to provide an accurate measurement of a Saturn day. But data gathered since then has rebuffed the idea.
But Tim Kennelly, a junior majoring in physics and astronomy at the University of Iowa, has made a significant observation about a process occurring Saturns's magnetosphere that is linked to the planet's seasons and changes with them. The find provides the breakthrough astronomers needed to accurately determine how time passes on Saturn and could also change our understanding of the magnetosphere on Earth.
The findings were made possible by data gathered from NASA's Cassini spacecraft, which has been in orbit around Saturn since 2004.
It turns out that Saturn's north and south poles each have their own "SKR days" that vary over periods of weeks and years. The find is one of the first direct observations of seasonal changes in Saturn's magnetosphere.
According to NASA officials, how these different periods arise and are driven through the magnetosphere has become a central question of the Cassini mission.
Moreover, the observation carries over to all planets having a magnetosphere, including Earth.
Kennelly looked at inward-moving "flux tubes" composed of hot, electrically charged gas, called plasma. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, he found that the occurrence of the tubes correlates with activity in the northern and southern hemisphere depending upon the season.
Kennelly also found that during winter in the northern hemisphere, the occurrence of flux tubes correlates with SKR period originating in the northern hemisphere. A similar flux tube and SKR correlation was noted for the southern hemisphere during southern winter. The events are strongly ordered and follow Saturn's seasonal changes, Kennelly said in the statement.
As for such an esteemed discovery coming from a student only three years into his undergraduate education, Kennelly remains modest.
"I'm pleased to have contributed to our understanding of Saturn's magnetosphere so early in my career," said Kennelly. "I hope this trend continues."
Kennelly is lead author of the paper published online in the American Geophysical Union's (AGU) Journal of Geophysical Research.