Pluto’s volcanoes are still active

For the second half of the XXand century, the geologists and planetary scientists suspected far from the importance of volcanism in the Solar systemstarting with the earth itself and its geodynamics controlled by the tectonic plates† Everything will change thanks to the development of thespace travel and in particular with the Travel missions who will make us discover the Io volcanismthe Moon infernal of Jupiterand the cryovolcanism of Triton around Neptune† Today we even wonder about possible eruptions underway on Venus and potential cryovolcanoes have even been detected on Titan, Saturn’s largest moon. In fact, there is already a large body of work on it volcanoes of the solar system as shown in the book Planetary Volcanism Across the Solar System co-author of Rosaly Lopezthe famous planetary scientist of the NASA

For several years now, researchers have also wondered whether there are volcanoes on the surface of Pluto but so far they had been rather wary of looking at the images provided by the mission new horizons in July 2015, during his only visit to the surroundings of the dwarf planet and his procession of moons.

What heat sources for the volcanoes of the solar system?

Indeed, it takes internal energy in the form of heat in a rocky celestial body to have volcanism, which the lavas issued from basalt melted or a mixture of water,ammonia and methanol as believed in cryovolcanoes. For planets like Venus and the earth, this warmth is a legacy of the process ofaccretion gravity and especially radioactive elements brought in during accretion. They have therefore received a supply of energy that is the weaker and the faster it will be depleted the smaller the planet. It is for this reason that there seems to be no more volcanic activity on the moon and mercury for a long time, even though we suspect that some eruptions are still possible in the case of the moon

In case of Io and D’EnceladusSaturn’s moon with geysersthey are supposed to be tidal forces who heats these? stars† This is not the case with Pluto today (except at the beginning of its history with the birth of its main moon, Charon), which is also smaller than the moon. Logically, therefore, you would not expect significant volcanic or other activity on Pluto’s surface, which would therefore be dead and heavily cratered.

As for this last point, it is certain that this is not the case, as the images of the plain show Sputniknamed after the first artificial satellite, which is a plain about 1,000 kilometers wide made up of ice fromnitrogen-methane and carbon monoxide† Indeed, it is relatively smooth and free of craters, to the point that it should probably only be less than 100 million years old. In addition, there is a polygonal structure that was first interpreted as a manifestation of cells of convection nitrogen/carbon monoxide ice. But recently, this interpretation has been called into question.

An unprecedented cryovolcanism

A team of planetary scientists recently published an article in: NatureCommunication where they explain that the images and data provided by new horizons strongly suggest that a region southwest of the Sputnik Plain does contain cryovolcanoes, but manifests in a way never seen before when considering other known cryovolcanoes in the solar system. However, this is not the first time the existence of this phenomenon on Pluto has been considered.

This region had already caught the attention of researchers in 2015 because it seemed very different from the others and since then the analyzes of the images and the topography it revealed have continued. According to planetary scientists, other geological processes have shown that cryovolcanoes to create the observed features are unlikely. For example, the area has significant differences between the elevations of the terrain’s fortunes that could not have been created by erosion.

Data on the chemical composition of the intriguing structures that have been detected suggest that it is mainly water ice. But given Pluto’s average temperature, about 40 Kelvin (-233°C), even taking into account a small additional component with ammonia or methanol, the supposed cryovolcanoes should not emit liquid water and the visible flows should rather be comparable to those of the glaciersalthough it is indeed a matter of movements of matter analogous to that of liquid lava spewed out by volcanoes.

This is enough to revive speculation about the exact energy sources that make Pluto a still-living celestial body.

One of the benefits of exploring new places in the solar system is that we find things we didn’t expect. These gigantic, eerie cryovolcanoes observed by New Horizons are a prime example of how we are expanding our knowledge of volcanic processes and geological activity on icy worlds. stated Kelsi Singer, assistant scientist on the project new horizons from Southwest Research InstituteBoulder, Colorado, and senior author of the published article.

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