The region that scientists suspect may conceal a subsurface ocean with life on Pluto was formed through a catastrophic event.
“The Heart of Life” on Pluto is the vast icy plain, which has a nearly perfect heart shape in images captured by NASA’s New Horizons spacecraft since 2015.
A recent study published in the journal Nature Astronomy indicates that this unusual heart has formed from nitrogen ice accumulating after a major, slow-moving impact.
A violent collision created Pluto’s heart-shaped ice field? – (Graphic: UNIVERSITY OF BERN)
The work, led by researcher Martin Jutzi from the University of Bern in Switzerland, employed a simulation method known as fine-grained hydrodynamics to investigate various impact angles and the size of the impacting object in the area known as Sputnik Planitia.
Sputnik Planitia is the western lobe of the heart-shaped icy plain, covering about 2,000 km2 and lying approximately 4 km below the surrounding area.
Pluto with its prominent heart-shaped structure on one side – (Photo: NASA).
The authors found that this shape could arise from a glancing blow, which created the elongated tail-like shape of one half of the heart.
The object that collided with Sputnik Planitia in the past was a massive icy rock with a diameter of up to 730 km.
Due to Pluto’s icy core, the impact did not melt or liquefy parts of the dwarf planet, unlike what occurs in collisions on other celestial bodies with warmer climates.
This mysterious icy object may have been flattened, and the remnants could be hiding somewhere beneath the fine nitrogen ice.
Additionally, the simulation from the team at the University of Bern brings somewhat disappointing news for astrobiologists, suggesting that there may not be a subsurface ocean beneath Sputnik Planitia.
Previously, some scientific groups had posited that a vast body of liquid water had kept the heart positioned near the equator rather than gradually shifting towards the poles during the celestial body’s evolution.
This perspective suggested that a subsurface ocean helped weigh down this ice field, allowing it to maintain its position near the equator. If it were merely ice, this heart would be too light and could easily “drift.”
Notably, the work from Hokkaido University, Tokyo Institute of Technology, Tokushima University, Osaka University, Kobe University (Japan), and the University of California, Santa Cruz (USA) stood out in this regard.
This group argued that the subsurface ocean could still be in a liquid state due to the presence of a layer of insulating clathrate hydrate gas between the ice shell and the ocean. Thus, they believe that the possibility of life existing remains.
However, according to the University of Bern team, the original cover was shattered by a meteoric impact, causing the heart to be heavy enough to move towards the equator without necessarily needing a subsurface ocean.
To arrive at a definitive answer, we must wait for additional space agencies to send more spacecraft to Pluto.
