The planet Saturn, shown here in a 2007 image from the Cassini spacecraft, rotates rapidly, so a "day" on the giant world lasts only about 10 or 11 hours. Because Saturn is made of gas, however, locking down that number is difficult. Astronomers use different techniques to measure the length of a day, producing varying estimates. [NASA/JPL/SSI]
You are here
Moon and Saturn
StarDate:
December 17, 2023It’s a long time between birthdays on Saturn. That’s because a year on the giant planet lasts about 29 and a half Earth years. That’s how long it takes the planet to complete a single orbit around the Sun. That adds up to a lot of days — more than 24 thousand sunrises and sunsets between birthday cakes.
The exact number of days has been a little unclear. Because Saturn is a big ball of gas, it’s hard to measure the length of its day. There aren’t any mountains or lakes or continents to track as the planet rotates. And different latitudes and depths can rotate at different rates.
Without solid landmarks, planetary scientists use other methods to measure the length of a day. They track features in the planet’s clouds, which give an approximate length. They look at features in Saturn’s rings, which are pulled along by the planet’s gravity. And they use spacecraft to track radio waves produced by Saturn's magnetic field.
Those methods have produced different results, ranging from about 10 hours and 14 minutes to 10 hours and 45 minutes. The best average is about 10 and a half hours — giving Saturn some pretty short days.
Saturn is in great view tonight. It looks like a bright star quite close to the Moon. They’re in the south-southwest as night falls, and set in late evening.
Script by Damond Benningfield
Get Premium Audio
Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.
