After decades of uncertainty, scientists have finally figured out the length of a day on Saturn.

Saturn’s peculiar magnetic field and landmark-free surface have long stood in the way of scientists’ ability to determine its rotation rate.

But, thanks to Cassini data, they’ve now solved the mystery.

Vibrations picked up by particles in the planet’s rings have provided a window into the movement of Saturn’s interior for the first time, revealing a day on the icy planet lasts just 10 hours, 33 minutes and 38 seconds.

According to a new study published in the Astrophysical Journal, the ring particles respond to vibrations within Saturn much like a seismometer might to an earthquake.

This gives rise to measurable wave patterns.

‘Particles throughout the rings can’t help but feel these oscillations in the gravity field,’ said Christopher Mankovich, a graduate student at UC Santa Cruz.

‘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.’

Previous efforts to narrow down the Saturn day estimated it to be 10 hours, 39 minutes, and 23 seconds based on what was known about its magnetic field from radio signals captured by the Voyager spacecraft in the 1980s.

Others, based on Cassini data, suggested it could fall anywhere between 10 hours and 36 minutes to 10 hours and 48 minutes.

Previous efforts to narrow down the Saturn day estimated it to be 10 hours, 39 minutes, and 23 seconds based on what was known about its magnetic field from radio signals captured by the Voyager spacecraft in the 1980s. A Voyager image of Saturn's rings is pictured above

Saturn’s magnetic field, however, is not a reliable source of information for working out a Saturn day because it aligns almost perfectly with the planets rotational axis.

‘The researchers used waves in the rings to peer into Saturn’s interior, and out popped this long-sought, fundamental characteristic of the planet,’ said Cassini Project Scientist Linda Spilker.

‘And it’s a really solid result. The rings held the answer.’

WHAT DID CASSINI DISCOVER DURING ITS 20-YEAR MISSION IN SPACE?

Cassini launched from Cape Canaveral, Florida in 1997, then spent seven years in transit followed by 13 years orbiting Saturn.

An artist's impression of the Cassini spacecraft studying Saturn 

In 2000 it spent six months studying Jupiter before reaching Saturn in 2004.

In that time, it discovered six more moons around Saturn, three-dimensional structures towering above Saturn's rings, and a giant storm that raged across the planet for nearly a year.

On 13 December 2004 it made its first flyby of Saturn's moons Titan and Dione.

On 24 December it released the European Space Agency-built Huygens probe on Saturn's moon Titan to study its atmosphere and surface composition.

There it discovered eerie hydrocarbon lakes made from ethane and methane.

In 2008, Cassini completed its primary mission to explore the Saturn system and began its mission extension (the Cassini Equinox Mission).

In 2010 it began its second mission (Cassini Solstice Mission) which lasted until it exploded in Saturn's atmosphere.

In December 2011, Cassini obtained the highest resolution images of Saturn's moon Enceladus.

In December of the following year it tracked the transit of Venus to test the feasibility of observing planets outside our solar system.

In March 2013 Cassini made the last flyby of Saturn's moon Rhea and measured its internal structure and gravitational pull.

Cassini didn't just study Saturn - it also captured incredible views of its many moons. In the image above, Saturn's moon Enceladus can be seen drifting before the rings and the tiny moon Pandora. It was captured on Nov. 1, 2009, with the entire scene is backlit by the Sun

In July of that year Cassini captured a black-lit Saturn to examine the rings in fine detail and also captured an image of Earth.

In April of this year it completed its closest flyby of Titan and started its Grande Finale orbit which finished on September 15.

'The mission has changed the way we think of where life may have developed beyond our Earth,' said Andrew Coates, head of the Planetary Science Group at Mullard Space Science Laboratory at University College London.

'As well as Mars, outer planet moons like Enceladus, Europa and even Titan are now top contenders for life elsewhere,' he added. 'We've completely rewritten the textbooks about Saturn.'

The discovery is just the latest bit of insight to come from the Cassini data even after the mission ended this past September.

During its many orbits of Saturn, it viewed the planet’s rings in greater detail than ever before.

‘Two decades later, in the final years of the Cassini mission, scientists analyzed mission data and found ring features at the location of Mark’s predictions,’ said co-author Jnathan Fortney, professor of astronomy and astrophysics at UC Santa and a member of the Cassini team.

‘This current work aims to make the most of these observations.’