New research suggests that liquid water could be common at the solar systems outermost regions and that Dwarf Planet Pluto may even have an ocean beneath its surface.
In 2015, NASA’s New Horizons spacecraft zoomed past Pluto making its way toward the Oort cloud. As it passed next to the dwarf planet, it turned its cameras toward Pluto and snapped a series of stunning images of the dwarf planet’s heart-shaped geography. On its way toward the outermost parts of the solar system, the spacecraft took a peek at Pluto’s “Dark Side.” Images of Pluto’s dark side have revealed striking geological features that have not helped scientists better understand Pluto and what the dwarf planet is like in its interior. One of the images New Horizons snapped shows black ripples of rock that happen to be on the opposite side of Sputnik Planitia, the basin that forms the left lobe of Pluto’s heart.
Does Pluto have a 93-mile-thick ocean?
These ripples offer new evidence that the dwarf planet may have a 93-mile-thick ocean (150 kilometers) between its crust and core. The findings, the result of data analysis submitted by the New Horizons spacecraft after its Pluto flyby in 2015, were presented at the Lunar and Planetary Science Conference, a virtual conference online in response to the Coronavirus pandemic. The impact that carved the Sputnik Planitia basin probably sent shock waves around Pluto that shattered the landscape on the other side, according to results that are yet to be peer-reviewed, first published in October.
What we know so far
Scientific American reports that signs of a similar event on Mercury are also evident, where a 1,528-kilometer-long impact crater lies exactly on the opposite side of the planet from a region of chaotic geography. “If the impact was large enough, the planet itself can act as a lens and focus the wave energy at the exact opposite point on the planet from the impact,” Adeene Denton, a planetary scientist at Purdue University, told Science News. So how do we know there’s an ocean hiding within our solar system’s favorite (ex)planet? When a cosmic body–say 450 kilometers (250 miles) wide–impacts a dwarf planet like Pluto, it produces a massive shock wave followed by a stress wave. These waves travel across the surface of the alien world.
As they move, they reveal clues
They also happen to cross through the center. However, waves travel at different speeds through different materials: They travel faster through the dwarf planet’s dense core, slower through an icy crust, and much lower through a liquid ocean. In other words, Pluto may have controlled how the shock waves caused by the impact traveled through the dwarf planet. And precisely, there is where experts should look for evidence for an ocean. By analyzing the cracks in the surface ice, scientists can obtain crucial data about the thickness of the proposed ocean and the core’s chemical makeup.
What computer simulations show
To understand more, Danton and her colleagues ran a series of computer simulations of an impact and looked for clues. The model, which is still in early development, offers additional, growing evidence that suggests there could be water on (inside) Pluto. Another study four years ago analyzed Pluto’s surface fissures, suggesting that an ocean beneath the surface may be a possible explanation.
The impact at Sputnik Planiti
A research paper published in 2019 suggests that the impact at Sputnik Planitia may have made its way through the dwarf planet’s cruise and caused the ocean to resurface. Once there, it froze, and it caused Pluto to tip into its current orientation. “To explain the lines seen on the dwarf planet, not only would Pluto need a large ocean, 150 kilometers or more in thickness, but the core must contain minerals, such as serpentine, that form through interactions between rock and water,” Danton revealed to Science news.