Scientists are excited by the discovery of what appears to be an enormous “cryovolcano” on one of Saturn’s moons.
Experts have been searching for years for proof that ice volcanoes exist on the surface of Titan, where temperatures are thought to be as low as minus 180C.
Dr Randy Kirk of the US Geological Survey (USGS), whose team created and analysed the maps, told news.com.au he was certain of the finding.
“When we see these mountains with holes blasted out of them and flows coming out, my colleagues and I think there’s not any other way to explain that than volcanism,” he said.
Dr Kirk’s team first studied an image of an area of Titan’s surface known as Sotra Facula in 2004. At the time it seemed promising, but not conclusive.
“We were lucky there was a second image that was taken that covered the same area,” he said.
“My group at the USGS developed the tools to take the two images and use them as stereo images and make a topographic map.
“When we did that we found that not only was the round feature a mountain, but there were huge depressions in the ground.
“There was a bite out of the peak of the mountain and a pit deeper than anything we’ve seen anywhere on Titan next to it, and additional mountains nearby in the flow area and beyond.
“It looks like a whole cluster of volcanoes to us. We were quite excited.
“The real ‘jumping up and down’ phase came when we made a little video of it (Cassini) flying over the thing.
“It turned out that really put everything in perspective and showed us what we were looking at better than just the topographic map itself.”
Instead of molten lava, ice volcanoes are generally thought to erupt a watery mixture that flows out and turns to ice.
Dr Kirk said while he was sure the formation was volcanic, there was nothing to say whether or not it was active at the moment.
“We really don’t have any evidence one way or the other,” he said.
“With the radar instrument we’ve measured the heat, the temperature of the surface in that area and that the time we looked at it, it was no warmer than the rest of the surface.
“It’s possible that like volcanoes on earth, an active volcano might only erupt once a century or something.”
From ice to life?
One of the reasons the existence of ice volcanoes on Titan is so interesting is that it could explain the presence of methane in the moon’s atmosphere.
“Calculations show that the Sun would basically destroy all of it (methane) in only about 10 million years, so somewhere there must be a source that’s replenishing it,” Dr Kirk said.
“Volcanoes would be a very good way to bring gases like methane out of the interior of Titan and keep the atmosphere supplied.”
Another reason is that it may suggest the existence of water under the moon’s surface — leading to speculation about the possibility of life.
Observational astronomer Dr Michael Brown of Monash University’s School of Physics told news.com.au that the idea excited many experts.
“The thing that is very intriguing about this it suggests that if this volcano is spewing out water, there might be liquid water somewhere under the surface of Titan,” he said.
“The reason people start thinking about life when they see something about this is that anywhere that we look on Earth we see life wherever there is liquid water.
“Titan is known to have a lot of organic molecules in its atmosphere and on its surface as well, so people are sort of thinking that if the building blocks of life are there, the liquid water is there, perhaps there’s life there.”
Dr Brown said it was far too soon to say anything for certain, but there was a reason for all the excitement.
“They don’t have any direct evidence for life yet, it’s just there are a couple of elements of the puzzle there and that’s getting people very excited,” he said.
“But there’s a good reason to be excited if there’s some things that could be primitive building blocks towards life and liquid water there.”
Dr Kirk said more research needed to be done to find out what sort of material was erupted by the volcano before it could be said to increase the chances of life-sustaining conditions.
“Now that we have a model that says we found a rather tall mountain and chips blasted out of the ground and flows that are rather thin, those will be the constraints for theoreticians to try and make models and say which chemical compositions might have been erupted,” he said.
“Hopefully in that way we can understand a little bit better what this volcano might be made out of.”
Dr Kirk added: “It’s been a privilege to explore Titan for the first time. It really is almost the most interesting body in the solar system after Earth, just because so many things are going on there.”