Was Pluto's “core” formed as a result of a celestial collision, or is there no underground ocean? |. Official website of Forbes Japan (Forbes Japan).

In 2015, NASA's New Horizons spacecraft sent back to Earth the first images of Pluto in human history. Since then, scientists have puzzled over a mysterious heart-shaped area on the surface of the dwarf planet.

A new simulation study published recently shows that the region known as Sputnik Planitia in the Tombo region was formed by a massive collision with a planetary body more than 640 kilometers in diameter. The size of the object is equivalent to the distance from north to south of the US state of Arizona.

Pluto was discovered in 1930 by Clyde Tombaugh, an American astronomer who worked at Lowell Observatory in Flagstaff, Arizona.

Ice shell

Sputnik Planitia is a white basin located near Pluto's equator and extends 2,000 kilometers long and 1,200 kilometers wide. It was discovered during the New Horizons flyby mission. Pluto's ice crust is particularly thin on the plains, where scientists believe there is an underground ocean isolated from Pluto's frigid environment.

However, in the specialized journal Nature Astronomy on the 15th of this month,PublishA paper summarizing this latest research also suggests that Pluto does not have an underground ocean.

Most of the surface

While most of Pluto's surface is made up of methane ice and its derivatives with a crust of water ice, “the region is full of nitrogen ice,” said Harry Ballantyne, lead author of the study and a researcher at the University of Bern in Switzerland. “Because this is a low-lying area, it was likely deposited quickly after the impact.”clarificationThey do.

An image showing the most important landforms on the surface of Pluto and their names. Sputnik Planitia is at the center, and the area surrounded by the white line is the Tombo region (NASA/Johns Hopkins University Applied Physics Laboratory/Southwestern Research Institute).

The essence of Pluto

“Pluto's core is so cold that even when it was heated by collisions, the underlying rocks did not melt and remained very solid,” Ballantine continued. “Due to the low angle and speed of the impact, the core of the impacting object was settled intact on top of Pluto's core, rather than sinking into it.”

It is thought that Sputnik Planitia's shape and position on the equator can be explained by oblique collisions with other planetary bodies, rather than direct collisions, and the flattening of the cores of the colliding bodies, rather than the presence of an underground ocean.

Important means

“The formation of Sputnik Planitia provides a very important way to learn about the early history of Pluto,” said co-author Aden Denton, a planetary scientist at the University of Arizona's Lunar and Planetary Laboratory (LPL). “By expanding our study to include more unique formation scenarios, we were able to learn some entirely new possibilities for Pluto's evolution, which may also apply to other Kuiper Belt objects.”

Kuiper belt

The Kuiper Belt is a donut-shaped region surrounding the outer solar system beyond the orbit of Neptune, and is thought to be home to icy bodies and comets.

Pluto is 40 times farther from the Sun than Earth, and it takes sunlight about 5 and a half hours to reach it. Because sunlight reaches only 1/1600 of the Earth's surface, surface temperatures can drop to -240°C.

(Forbes.com original text)