A new study suggests that each year, over a 4.5 billion life, ice volcanoes on the dwarf planet Ceres generate enough material to fill a standard cinema room. This is an amazing analysis, since we managed to calculate the rate of cryovolcanic activity from observations, and the results help us understand where the rest of the mountains are.
In 2015, NASA's Dawn spacecraft spotted the icy volcano Akhuna with a height of 3 miles. This is a young geological formation (not older than 200 million years). That is, it no longer erupts, but was active in the recent past. Youth and loneliness Akhuna seem incredibly mysterious. It would be strange if Ceres existed calmly and suddenly broke out at one point. Where, then, are the other volcanoes and why is Ahuna alone?
Last year, scientists suggested that evidence of the presence of ancient volcanoes over time was erased due to “viscous relaxation”. Viscous material, like honey or putty, can begin as a dense drop whose weight causes it to leak into a flatter shape. Rocks do not do it at normal temperatures, but with ice everything is different. Ceres consists of ice and stone, so there is a theory that the formations on the dwarf planet move under their own weight, like terrestrial glaciers. The composition and temperature of the beds affect how quickly they relax in the surrounding landscape. The more ice, the faster it flows. The lower the temperature, the slower it flows.
The Ceres rate never exceeded -30 degrees Fahrenheit, but the temperature varies across the surface. The poles are cold enough, but at the equator is warmer, so the mountain is changing. Computer simulation has shown that such a theory is viable. The model cryovolcanoes in Ceres remained frozen for centuries, but at other latitudes they activated and with time became more rounded.
To confirm the fidelity of computer models, the researchers studied topographic observations of the Dawn ship orbiting Ceres since 2015. Over a length of 1 million square miles, the team noticed 22 mountains, including Akhuna, which corresponded to the models.
Polar mountain Yamor seems old and beaten, but in form it resembles Akhun. It is 5 times wider than its height. Other mountains are endowed with lower proportions. The volume of volcanoes was estimated by studying their topography. By combining age and volume, the researchers obtained the rate of formation of cryovolcanoes in Ceres. It turns out that one volcano appears every 50 million years. These figures are more than 13,000 m 3 cryovolcanic material each year, which is enough to fill a cinema or four Olympic pools. This is less than the earth’s figures (1 billion cubic yards per year). In addition, instead of explosive eruptions, cryovolcanoes create the icy equivalent of a lava dome. This is a cryomagma - a salty mixture of rocks, ice and other volatile substances.
The causes of cryovolcanic activity are still a mystery, but future studies will find answers, because signs of ice volcanoes have been noticed on other bodies of the Solar System. There are suspicions that cryovolcanoes will be found on Europe and Enceladus (satellites of Jupiter and Saturn), along with Charon (Pluto's moon). Europe seems to be the most interesting, as it has a liquid ocean under the ice shell.