LOUISVILLE, Ky. (WDRB) -- NASA scientists recently announced they'd solved a major mystery about Saturn: the length of a day on the ringed planet. But a University of Louisville professor made a similar discovery 10 years ago.

Dr. Timothy Dowling is director of the atmospheric science program at the University of Louisville. Ten years ago, Dr. Dowling and two colleagues set out to figure out the length of a day on Saturn. It's a question that's stumped scientists for hundreds of years.

"We've been trying to figure out the length of Saturn's days since the 1790s and it's very difficult," said Dr. Dowling.

Why? While on earth, scientists can just track landmarks, like mountains, to figure out time. But Saturn is made of gas, so there are no solid landmarks on the surface to track rotation and an unusual magnetic field hid the planet's rotation rate.

"We just threw our hands up, and no one knew what the length of a day on Saturn was," he said.

Dr. Dowling and his colleagues were able to measure waves in the atmosphere using data from NASA's Cassini spacecraft.

"We got a number of 10 hours and 34 minutes. But how do we know we're right?" said Dowling.

For a decade, Dr. Dowling waited for his Saturn data to be confirmed. Then just last week another group from NASA got the same exact number.

"We actually have two observations independently get the same number. That's how science works. So we've been repeated and confirmed and we now know the length of a day on Saturn," he said.

They too used Cassini data, but this time the answer was in the rings.

"Now they have very intricate, very wispy little waves in the inner ring of Saturn," said Dr. Dowling.

Both teams got 10 hours 34 minutes.

"To have that confirmed is just the icing on the cake," he said.

Dr. Dowling says the next step is to get it down to seconds. Scientists can then use that information to learn more about the rest of the galaxy.

"To understand how the planets were put together and also how they evolved and that actually tells us how we evolved. And how planet earth became habitable," said Dr. Dowling.

Dr. Dowling will be discussing Cassini discoveries on February 1 at Gheens Science Hall and Rauch Planetarium. The talk is from 6:30 p.m. to 7:30 p.m. and is free and open to the public.

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