Ever wonder how long a day on Saturn is? Well, now we know, thanks to new data from NASA’s Cassini spacecraft.
The gas giant has recently been the focus of a study on the age of its iconic rings — which turned out to be a lot younger than previously believed, per a previous report from the Inquisitr.
Fresh data on the rings of Saturn has also helped scientists solve a decade-old enigma by finally revealing how long a day on Saturn lasts. The answer: exactly 10 hours, 33 minutes and 38 seconds, reports NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
“The figure has eluded planetary scientists for decades, because the gas giant has no solid surface with landmarks to track as it rotates, and it has an unusual magnetic field that hides the planet’s rotation rate,” explains JPL, which designed, developed, and assembled the Cassini orbiter, and manages the Cassini mission for NASA’s Science Mission Directorate in Washington.
The length of time it takes for Saturn to complete a full rotation around its axis — or the length of a day on Saturn — was finally unveiled after scientists took a closer look at its icy rings. Upon examining Cassini’s detailed observations of Saturn’s rings, researchers led by Christopher Mankovich, a graduate student in astronomy and astrophysics at University of California Santa Cruz, uncovered wave patterns within the rings, which were found to mirror movements deep within Saturn’s interior.
According to the scientists, Saturn’s core emits vibrations occurring at frequencies that have an impact on the planet’s gravitational field. These vibrations produce a series of oscillations that ripple through the field and are then picked up by Saturn’s rings — much like a seismometer detects earthquake waves rumbling in beneath the ground.
“Particles throughout the rings can’t help but feel these oscillations in the gravity field,” said Mankovich.
“At specific locations in the rings these oscillations catch ring particles at just the right time in their orbits to gradually build up energy, and that energy gets carried away as an observable wave.”
The new data enabled Mankovich to create models of Saturn’s inner structure and match them with the waves observed within the rings. This ultimately helped track the movements of the planet’s core and discover its rotation rate.
This is not the first time that scientists have tried to unravel Saturn’s rotational period. In 1981, magnetic field data acquired by NASA’s Voyager spacecraft provided an estimate for Saturn’s rotation rate of 10 hours, 39 minutes, and 23 seconds. Previous Cassini data had placed the gas giant rotation rate between 10:36 and 10:48. These latest observations, which also relied on magnetic data, narrowed it down to 10:33:38 — several minutes faster than the Voyager estimates.
While a day on Saturn lasts less than half a day on Earth, a year on the gas giant is as long as 29 Earth years, notes JPL.
The reason why Saturn’s emblematic rings were instrumental in finding out its rotation rate has to do with the fact that this planet — unlike Earth, or Jupiter for that matter — has its magnetic axis nearly perfectly aligned with its rotational axis. shows a news release from UC Santa Cruz.
“We now have the length of Saturn’s day, when we thought we wouldn’t be able to find it,” said Cassini Project Scientist Linda Spilker.
“They used the rings to peer into Saturn’s interior, and out popped this long-sought, fundamental quality of the planet. And it’s a really solid result. The rings held the answer.”
The results of this exciting research were published yesterday in the Astrophysical Journal.