A new discovery raises questions about whether there is an underground ocean on Pluto.
Two weeks after the scientists at NASA’s New Horizons mission published a study showing that the planet has an underground ocean, another team put forward an alternative explanation for how the characteristic heart-shaped pool formed.
A new document published on Wednesday in the journal Nature suggests that the formation of the basin began not from the impact of a comet or other influential body, but from the mass of ice collected on the surface. This explanation does not require an ocean.
“This is a path without an ocean that explains the features of Sputnik Planitia,” wrote an astronomer from the University of Maryland, Douglas Hamilton, in a letter.
“Although Pluto does not need an internal ocean, there is nothing in my research that would oppose its presence,” he added.
Computer simulations show that Pluto’s ice resembles the Greenland ice sheet and can alone form a basin by clicking on the underlying crust.
“The idea that the pool was created from a mass of ice came at the end of the creative process,” said Hamilton. “Initially, I focused on explaining the location of ice caps (Sputnik Planitia’ ice) on the surface of the planet. This feature is centered on 25 north latitude and 175 longitude, almost opposite the gigantic moon of Charon. ” “Coming up with a viable scenario to explain these observations, I realized that the idea of influences limits successful models to small groups of impact sites. Although there is a more reliable option that could explain the location of the ice caps under any initial conditions, ”he wrote.
“My model does not rely on exposure. But you still need to explain why these ices are found in a deep pool. I believe that it appeared just because of the huge weight of the massive ice cap - the planet's crust bends slightly under the weight, just as it did in Greenland, Canada and Scandinavia during the last ice age. This is a natural explanation of the coincidence in the location of the ice cap and the pool, ”said Hamilton.
A new study suggests that the ice sheet formed early when the rotation of Pluto was fast, and the pool itself appeared later. The ice cap creates a slight asymmetry that turns towards or away from Charon when the planet’s rotation slows down to correspond to the orbital motion of the moon.
The unusual location of the ice is associated with the climate and axis of rotation of the planet, bent at 120 degrees (on Earth - at 23.5 degrees). This was written in a press release from the University of Maryland. “Modeling the temperatures of the dwarf planet showed (taking average values for the 248-year orbit of Pluto) that the places at 30 degrees to the northern and southern latitudes are the coldest locations. Their temperature is lower than at any pole. Ice would form in these areas naturally. This also applies to the Sputnik Planitia center, ”the press release says.
Over time, the ice field attracts even more ice cover, reflecting the solar side of light and heat. This maintains low temperatures (“runaway albedo effect”).
Since the pool is larger than the volume of ice filling it, scientists believe that Sputnik Planitia has been losing mass for a long time.
Pluto is only the third object in the Solar System, along with Earth and Mars, capable of boasting ice caps.
