The heart-shaped structure on Pluto's surface was a mystery for years. Now a group of researchers has revealed the secret behind Pluto's "heart."
Munich - NASA researchers were certainly amazed when the New Horizons space probe sent images of the surface of the dwarf planet Pluto back to Earth in 2015. The space probe had been traveling for over nine years to explore Pluto and the Kuiper Belt and to take images in the distant regions of our solar system. Images from New Horizons, which passed the dwarf planet on July 14, 2015, showed a white, heart-shaped structure on the surface - Pluto's heart was born. For years, researchers around the world puzzled over the origins of the heart - now they have achieved a breakthrough.
After years of puzzling – researchers find explanation for Pluto’s “heart”.
An international team of astrophysicists led by the University of Bern and members of the National Center of Competence in Research (NCCR) PlanetS has succeeded in reproducing the formation of the heart-shaped structure in a simulation. The heart was formed as a result of a collision with another planetary body with a diameter of almost 700 kilometers. The findings were published on Monday (April 15) in the journal Nature Astronomy.
Collisions between planetary bodies are not unusual in themselves. The heart-shaped structure on Pluto's surface puzzled the researchers primarily because of its unusual shape, the geological composition and the height profile of the surface. In their calculations, the astrophysicists focused primarily on the formation of the Sputnik plane - the western, teardrop-shaped part of the “heart”.
Collision with a planetary body formed surface of Pluto
The Sputnik Plain covers an area of 1,200 by 2,000 kilometers - about a quarter of the area of Europe - and is three to four kilometers deeper than the surrounding areas. “The elongated shape of the Sputnik plane strongly suggests that the impact was not a direct head-on collision, but rather an oblique collision,” Martin Jutzi, co-author of the study, said in a University of University publication Bern.
The research team therefore tried to simulate the collision by varying the speed and angle of the colliding body as well as the composition of Pluto's surface. The researchers were able to reconstruct the collision in the simulation. The low speed and the special angle of incidence of the other planetary body, as well as the structure and temperature of Pluto's surface, ensured the special nature of the Sputnik plane.
Researchers solve mystery: Collision led to the creation of Pluto's “heart”
The publication also shows that the core of the planetary body that collided with Pluto is probably still below the Sputnik plane. “Somewhere beneath Sputnik is the remnant core of another massive body that Pluto never fully digested,” said Erik Asphaug of the University of Arizona. The reason for this is said to be the extremely low temperature of Pluto's core. As a result, the surrounding rock did not melt due to the heat of the impact and the core of the planetary body did not sink to the core of Pluto.
The simulation also provides evidence of the existence of a subterranean ocean on Pluto. According to the laws of physics, the deepening of Sputnik's plane should have migrated to the pole of the dwarf planet over time. The previous theoretical explanation for the absence of this movement was the existence of a subterranean ocean.
New study contradicts – but no underground ocean on Pluto?
However, the new study offers an explanation that does not involve an ocean. The collision and the subsequent deposition of the impactor's core material could have resulted in a local mass excess, which would explain the lack of migration to the poles. If this approach proves correct, Pluto would not have an underground ocean - or only a very thin one.
(fd)