In the past, astronomers found it difficult to track the rotational speed of Saturn, because it lacks measurable solid surfaces and is covered by thick layers of clouds, foiling direct visual measurements by space probes.
Saturn has presented a great challenge to astronomers, as different parts of this sweltering ball of hydrogen and helium are known to rotate at different speeds, whereas its rotation axis and magnetic pole are aligned.
However, a new method offers insight into the internal structure of the planet, its weather patterns, and the way it formed. This method helped astronomers to determine Saturn’s correct rotational speed. The method was developed by Dr. Ravit Helled of the Tel Aviv University, Dr. Eli Galanti and Dr. Yohai Kaspi of the Department of Earth and Planetary Sciences at the Weizmann Institute of Science. The method is based on Saturn’s measured gravitational field and the unique fact that its east-west axis is shorter than its north-south axis.
The method suggests that Saturn’s days are about 6 minutes shorter than what you’ll find in current textbooks about our solar system.
“While 6 minutes may not seem like a big change, it will cause scientists to drastically change how they think about how winds in the ringed planet’s atmosphere blow. We used to think that we knew the rotation period,” said Helled.
In the past, the Voyager spacecraft that flew past Saturn in the early 1980s measured the planet’s rotational speed as 10 hours and 39 minutes, while the Cassini spacecraft, which went into orbit around the planet in 2004, came up with a figure of 10 hours and 47 minutes.
However, Helled and her team used Saturn’s magnetic field to deduce its spin rate, which was 10 hours, 32 minutes and 45 seconds. That is at least 6 minutes faster than the Voyager’s measurement.
The researchers have stated that the findings will help researchers in understanding planet’s atmosphere and how the heavy elements in its interior, such as water and rocks, are affected by the speed of the planet’s rotation.
The findings were published in the Nature journal.