Discover the giant ocean on Pluto

The giant heart shape on Pluto has long been a mystery. Recently two research groups said it was possible that this was a giant ocean.

Pluto may contain a giant ocean beneath the ice crust, according to researchers on the planet's surface.

The New Horizon spacecraft in 2015 recorded the heart-shaped image of the Tombaugh Regio . The "left lobe" area of ​​the "heart" is created by 1,000km Sputnik Planitia . This area may have been formed after a meteorite crashed into the surface of Pluto years ago, creating a volcanic crater filled with nitrogen.

However, scientists still cannot explain why the Sputnik Planitia ice region is near the equator of Pluto and almost directly opposite the Charon satellite. Scientists point out that only 5% of the chances of it being in such a position are accidental.

The Sputnik Planitia region stretches 1,000km.(Photo: The Guardian).

Existing in articles published in the prestigious Nature journal, the two research groups said they had the answer: Pluto is likely to contain a giant ocean beneath its ice cover.

"It can be said that this ocean has the same mass as the oceans on Earth. Pluto is smaller than Earth, but this ocean is very deep, can be as deep as 100km" - Francis Nimmo from University of California and Santa Cruz , co-author of the studies, said. They also added that the ocean is capable of spreading across Pluto.

According to Nimmo, meteorite impact on Pluto has created a huge amount of ice, causing the crater to have only a thin layer of ice at the bottom. If an ocean exists below this ice, it can be liquid - or in the mud. Also because frozen nitrogen accumulates in the basin over time, the volume of this area will become larger than before the impact, Nimmo said. This massive mass can cause Pluto to tilt.

Pluto may contain a giant ocean beneath the ice cover.(Photo: The Guardian).

"There are two things going on" - Nimmo said - "The rotation of Pluto is pulling this giant mass towards the equator and the gravitational force of the satellite object Charon will push it below the satellite or in opposite, whichever is closer ". As a result, the Sputnik Planitia glacier is still in the current position, near the equator of Pluto and away from the satellite object Charon.

Research shows that without the influence of the ocean, the nitrogen ice layer needs to be more than 40km thick before there is enough weight to make the Pluto turn. Scientists think this is a very unreasonable perspective.

The second study from researchers in the US and Japan also suggested that Pluto could be overturned. Cracks in the ice crust match its direction, along with the slow freezing of the ocean below the surface.

But researchers also say there is another possibility. It is possible that substances ejected by meteorite collisions may fall around the crater's edge. They can remove the holes and then the accumulated nitrogen ice creates extra volume large enough to cause Pluto to tilt.