June 16, 2024
1 Solar System Way, Planet Earth, USA
Space

Pluto's ocean is super salty, scientists say

Pluto's Ocean: Partial view of a rocky, planet-like sphere with a large smooth region covering most of the right side.
View larger. | from NASA New Horizons The spacecraft captured this view of Sputnik Planicia when it passed near Pluto on July 14, 2015. The large ice-filled basin forms the western half of the famous heart formation on Pluto. Fractures and bulges on Sputnik Planitia indicate that Pluto's ocean beneath the surface is slightly denser and saltier than Earth's oceans. Image via POT/ JHUAPL/ SWRI.
  • Pluto is small and far from the sun.. You wouldn't expect it to have liquid water.
  • But scientists believe Pluto has an ocean, beneath a thick layer of ice.. The evidence came from the New Horizons spacecraft's pass by Pluto in 2015.
  • New research, published in May 2024, suggests that Pluto's ocean is slightly saltier and denser than Earth's seawater. If you could take a dip, you would float easily, the scientists said. Cracks and bulges in the Sputnik Planitia impact basin provided clues about the salinity and density of the ocean.

A salty ocean on Pluto

The outer solar system, where Pluto orbits, is sometimes called deep freeze. It's a cold, desolate place, with Pluto so far from the sun that, from its vantage point, the sun looks like a bright star. However, Pluto is believed to have a liquid ocean beneath its icy crust. That makes Pluto similar to some moons in the outer solar system, such as Europa on Jupiter or Enceladus on Saturn. from NASA New Horizons The mission discovered evidence of Pluto's underground ocean when it passed by this world in 2015. This month (May 21, 2024) researchers released More details about the ocean hidden under Pluto's crust. They now believe it is a little denser or saltier than seawater on Earth. If you could take a dip, they said, you could easily float in it, just as you can easily float in exceptionally salty seas on Earth. like the dead sea.

Alex Nguyen at Washington University in St. Louis in Missouri, and Patrick McGovern at the Lunar and Planetary Institute in Houston, Texas, published his new peer reviewed findings in the magazine Icarus (Science Direct/ Elsevier) on February 15, 2024 (finalized version).

Looking at Pluto's ocean

Pluto's ocean is well hidden beneath a thick outer crust of nitrogen, methane and water ice. We will never be able to see it from a spaceship. But New Horizons' instruments were still able to detect the ocean far below the surface. Nguyen and McGovern used that data to find more clues about the nature of the ocean. In fact, the discovery came as a surprise to planetary scientists. Most calculations prior to New Horizons had suggested the existence of some ocean within Pluto. ought They froze shortly after Pluto formed and cooled rapidly. Nguyen saying:

Pluto is a small body. It should have lost almost all of its heat shortly after forming, so basic calculations would suggest that it is frozen to its core.

Later studies using data from New Horizons suggested that Pluto did indeed have an ocean. Paper fixed:

The existence of an ocean of water beneath the surface of Pluto has been inferred for numerous reasons. The characteristics of that ocean are vital inputs for various types of modeling being carried out to illuminate the interior structure and evolution of Pluto, especially in light of the complementary relationship between the dimensions of the ocean and an outer layer of water ice. .

Sputnik Planicia

The new study focused on the huge impact basin called Sputnik Planitia. This basin is part of the famous heart formation on Pluto and has many cracks and bulges in the ice. A massive meteorite impact created the basin billions of years ago. Nguyen and McGovern created mathematical models to try to explain the formation of cracks and bulges.

The results supported other studies, which point to a subsurface ocean of water beneath the basin. They estimated that the ice sheet over the ocean was between 40 and 80 kilometers (25 and 50 miles) thick. It is that impressive layer of ice that prevents the ocean from freezing completely.

Long nose cutaway view of the interior of the planet with several different layers and black text labels on a white background.
Pluto's ocean lies far beneath an icy crust of nitrogen, methane and water. Its salinity and density are only slightly greater than seawater on Earth. Image via Howett et al./ Research Gate (CC BY 4.0).

You could float in Pluto's ocean

The findings also provide more information about the salinity or density of the ocean. It turns out that it is not much different from Earth's oceans. The study suggested that Pluto's ocean is only 8% saltier than Earth's seawater, at most. That is similar to Great Salt Lake in Utah. If it were somehow possible to get to the ocean, a person could easily float in it.

Cracks in the surface of Sputnik Planitia provided clues to its density. like paper described he:

The density of Pluto's interior ocean affects the state of stress in the icy layer above.

If the ocean were less dense than it is, there would be many more fractures and the ice sheet would collapse. On the other hand, if it were denser, there would be fewer fractures than they observed. like nguyen noted:

We estimate a kind of Goldilocks Zone where the density and thickness of the shell are correct.

Bottom line: A new analysis of data from NASA's New Horizons mission shows that Pluto's ocean is slightly denser than seawater on Earth. You could easily float in it.

Source: The role of Pluto's ocean salinity in supporting nitrogen ice loads within the Sputnik Planitia basin.

Via Washington University in St. Louis

Read more: How Pluto got his heart

Read more: Ripples on Pluto hint at an underground ocean

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