This volcano erupts in ice instead of molten rock (video)

Ahuna mons
Public Domain Image from Dawn's low-altitude mapping orbit, from an altitude of 240 miles. (NASA)

It may be 3.1 billion miles away, but Ceres’ Ahuna Mons is nonetheless a spectacular thing.

We may be accustomed to our vibrant blue sky, day-glo fuchsia sunsets, clouds that explode with electricity, and wind that can level buildings – but these are the kinds of things that serve to remind us that our planet is just as otherworldly as other celestial bodies. On particularly dramatic days I sometimes feel like I’m living in a sci-fi movie.

There are all kinds of things going on in this amazing universe, but right here in our very own solar system we have a dwarf planet, Ceres, with a pretty nifty trick. Well, a lot of nifty tricks actually, but this one was just published by a team of scientists working with NASA's Dawn mission. What they conclude in their research is that the mountain called Ahuna Mons is a volcanic dome unlike any seen elsewhere in the solar system. It’s a cryovolcano – an ice volcano that erupts a liquid made of volatiles such as water, instead of silicates.

"This is the only known example of a cryovolcano that potentially formed from a salty mud mix, and that formed in the geologically recent past," says Ottaviano Ruesch of NASA's Goddard Space Flight Center. "Geologic activity was discussed and debated among scientists: now we finally have observations testifying to its occurrence."

ceres© Approximate true-color image of Ceres. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/Justin Cowart)

At nearly 3 miles high and 11 miles wide at the base, Ahuna Mons is a significant structure on the dwarf planet; while Ceres is the largest body in the asteroid belt, it is still only 600 miles wide. Rather than the extreme heat of the types of volcanoes we’re accustomed to on our own orb, Ceres’ ice volcano is the result of low-temperature volcanic activity – where molten ice -- water, usually mixed with salts or ammonia -- replaces the molten silicate rock erupted by terrestrial volcanoes. Ahuna’s dome was built by repeated eruptions of freezing water.

ahuna mons© Dawn Science Team and NASA/JPL-Caltech/GSFC

"There is nothing quite like Ahuna Mons in the solar system," said Lucy McFadden of NASA Goddard, a co-author on the paper. "It's the first cryovolcano we've seen that was produced by a brine and clay mix." The solid worlds in our solar system form a continuum from heavier, denser materials closer to the sun, such as the rocky terrestrial planets, to less dense, more volatile materials farther out, such as the icy moons of the giant planets and the Kuiper Belt objects, according to NASA. "Ceres, which orbits between Mars and the gas giant Jupiter, is interesting because it appears to be a transition object – it's not completely rocky, but it's not an ice world either," says McFadden.

As Dawn completes its low altitude phase of the Ceres mission – where it has been working from a distance of 240 miles – it prepares for the next phase which will take it to a higher altitude to gather more information from a new vantage point. We can only imagine what other wonders will be discovered about this queen of the asteroid belt.

Learn more about beautiful Ceres and Ahuna Mons in the video below.

Tags: Nasa | Nature | Space

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