Mid Wales scientist finds it's raining on Saturn

Dr James O'Donoghue led a team which discovered that it's raining on Saturn – and that the giant planet's amazing rings are the cause.

Now working for NASA in Boston, Dr O'Donaghue was born in Newtown and made the incredible discovery while working with a team from the University of Leicester, where he studied his PhD.

"We found that tiny water-ice particles that compose the planet's distinctive rings are continuously eroded away and then deposited into the planet's upper atmosphere as 'ring rain'," he said.

• Saturn is the second largest planet in our solar system

• It has a small rocky core covered with liquid gas

• Its rings stretch out into space for thousands of kilometres

• Some of the rings’ ice crystals are as big as houses – others as small as dust

• Saturn is very light as it is made up of more hydrogen than helium so it is less dense than other planets

• Like Jupiter, Saturn has many moons which surround it

• Saturn is not a peaceful planet – storm winds race around the atmosphere at around 800kmp/h[/breakout]

"We estimate that one Olympic-sized swimming pool of water is falling on Saturn every day. This is actually a minute amount, given the size of Saturn and its ring system. It would take several billion years to extinguish the rings at that rate.

"But we were amazed to discover that the water input over just eight hours was visible in Saturn's atmosphere from ground-based telescopes."

The study was prompted by images taken in the early 1980s from NASA's Voyager spacecraft, which showed two to three dark bands on Saturn.

At the time, and scientists theorised that water could have been showering down into those bands from the rings, but were not able to observe the bands again until 2011 when Dr O'Donaghue's team used the Keck Observatory in Hawaii to make observations for two hours, seeing parts of the planet that had never been mapped in such detail before.

The team found that charged water molecules rain down only on certain parts of the planet, which showed up darker in the images from Keck.

Dr O'Donoghue then found a connection between those parts of Saturn and the parts of the rings which contained a lot of ice.

"The most surprising element to us was that these dark regions on the planet are found to be linked via magnetic field lines to the solid portions of water-ice within Saturn's ring-plane," he said.

"What we observed was a series of light and dark bands, with areas of reduced emission corresponding to water-dense portions of Saturn's rings and areas of high emission corresponding to gaps in the rings.

"Saturn is the first planet to show significant interaction between its atmosphere and ring system."

The discovery not only helped explain the mystery of the dark lines across the planet, but also helps scientists to better understand the origin and evolution of Saturn's ring system and changes in the planet's atmosphere.

And the study also could explain why each of Saturn's rings is a different density and size. The magnetic field that makes it rain in certain areas of the planet also could control the size and composition of the rings.

Dr O'Donaghue's grandmother Rona, who lives in Shrewsbury, said his family are delighted with the discoveries he has made.

She said: "We are very proud of James. He has worked extremely hard to realise his dream, he has always had a keen interest in science and astronomy."

After going to school at Maesyrhandir Primary and Newtown High School, Dr O'Donaghue studied for a physics degree at Aberystwyth, working at Morrison's supermarket to earn money towards his studies.

He completed his doctorate at Leicester University and now works for NASA as a post-doctoral researcher based at Boston University, Massachusetts, USA, and has visited observatories all over the world to help set up ground-based telescopes.

The rings of Saturn have been of interest to scientists since they were first observed by Galileo Galilei in 1610. But although Galileo was the first to observe them, he didn't know what they were, describing them as "ears" on either side of the planet.

Christaan Huygens first proposed that Saturn was surrounded by a solid ring in 1655, and in 1675 Giovanni Cassini discovered the largest gap in the ring system, now named the Cassini Division.

Scientists now know that Saturn has more than 30 rings thanks to the Cassini spacecraft which is orbiting the planet.

Each ring is made of particles ranging from tiny, dust-sized icy grains to a few particles as large as mountains. The rings are believed to be pieces of comets, asteroids or shattered moons that broke up before they reached the planet.

While the other three gas planets in the solar system – Jupiter, Uranus and Neptune – also have rings orbiting around them, Saturn's are by far the largest and most spectacular.