Millions of years ago, Ceres' surface might have had plenty of icy volcanoes to keep Ahuna Mons company. Scientists have always found its solitary existence weird anyway. "Imagine if there was just one volcano on all of Earth," University of Arizona in Tucson's Michael Sori said. "That would be puzzling." That's why Sori and his team from the university's Lunar and Planetary Laboratory explored the idea that Ceres used to have many other cryovolcanoes. After taking what we know about the dwarf planet into account, the researchers were able to come up with one possible explanation for the land formations' disappearance: they may have flattened out over time.
They believe the volcanoes disappeared due to viscous relaxation, a term used to describe the idea that any solid material will flow if you give it enough time. Since it's the same reason why glaciers flow on Earth, it doesn't sound crazy that volcanoes partially made of ice could go through the process. Especially since Ceres is located between Mars and Jupiter, closer to the sun than other ice-covered worlds like the moons Europa and Titan.
The team created a model to see if it's actually possible for icy mountains to flatten out, and they came to the conclusion that they have to be at least 40 percent water ice. Further, it probably took hundreds of millions of years for them to disappear. Ahuna Mons might just be relatively young at 200 million years old -- it could also end up vanishing in the end.
The researchers are planning to look for and identify any remnant left by the flattened volcanoes. Southwest Research Institute's Kelsi Singer says: "Because all of the putative cryovolcanic features on other worlds are different, I think this helps to expand our inventory of what is possible." If the team does find residue of ancient ice volcanoes, then scientists are bound to look for their presence on other icy moons and planets.