The latest images from the NASA New Horizons spacecraft have led to the conclusion that Pluto could hide, under an icy layer, a thick and cold underground ocean, composed of a kind of frost or sleet. The discovery has been published in the journal Nature and directly puts this dwarf planet on the list of candidate celestial bodies to have a sea inside (and to host life).
The dwarf planet has very particular geological characteristics. Its surface has fractures and one region in particular has always caught our attention: a bright area that became famous for its curious and striking heart shape . Going deeper into this territory, specifically in Sputnik Planitia, which is 1,000 kilometers in diameter, scientists have discovered that just below the plain, behind an icy layer, there may be a somewhat viscous and very cold liquid ocean (the temperature Pluto mean is -230º C).
The researchers (from the University of California at Santa Cruz and the Lunar and Planetary Laboratory of the University of Arizona (USA)) wanted to find out why this area was located near the equator of the dwarf planet. The explanation is that the collision of an object in the past left a crater whose hole was filled with nitrogen ice and, probably, water in a liquid state that, finally, would form an underground ocean, modifying the total mass of the planet until it rotated and place it in its usual position, in such a way that the heart-shaped plain is always facing away from the moon Charon . And it is that the Sputnik plain was extremely well aligned with Pluto’s tidal axis. This is the explanation.
According to the calculations that integrate both the size of this frozen world at the end of the solar system and its internal heat flow (temperatures, pressures …), this ocean would be semi-melted , as if it were a gigantic hailstorm. Additionally, the ocean may contain ammonia, “a good antifreeze,” experts say.
The New Horizons probe, responsible for this study, is now traveling towards a new object in the Kuiper belt called 2014 MU69 , whose encounter is scheduled for January 1, 2019.
