Pluto elevation map

Pluto Ocean of Mystery – Trapped Under Ice

Pluto Ocean – Hidden Oceans of Far Worlds

A Buried Pluto Ocean!

Thanks to Hubble Space Telescope and revolutionary methods in astronomy, more structural Pluto facts became available with 1990’s. Simultaneously, scientists initiated discovery of many other Kuiper Belt objects.

Consequently, detailed analysis pointed out presence of water ice on Pluto. Domination of water ice and some other characteristic features brought possibility of a buried ocean of water beneath kilometers of icy Pluto surface as well as other similar frozen planets.

In previous years, there has been some ideas about how those subsurface oceans can form and maintain liquid form.

Eventually, recent simulations prepared by a team leaded by Shunichi Kamata from Hokkaido University reflects more possibilites for a Pluto ocean now.

Related article and the simulation results published in Nature Geoscience on May 2019.

Inner Layers of Pluto
General view of Pluto’s geological and atmospheric layers. Source: NASA

Pluto Ocean – Background of Knowledge

Beginning with the grand New Horizons Mission‘s invaluable approach to Pluto System, many interesting features of our sidelined fellow Pluto started to flow. After the famous flyby in July 2015, we now have basic and more solid knowledge about the planet. However, the knowledge about those facts is mostly limited with what scientists can see: Surface and atmospheric features.

When it comes to internal features of planets, it generally remains uncertain or dependent to simulations. Because our current methods for analyzing inner layers of rocky planets do not reveal all the secrets yet.

We have a good example of a big rocky laboratory to construe though: The Planet Earth. Exploring more of the physical behaviours of Earth and tracking them millions of years back means understanding others more.

How Can Pluto Have A Buried Ocean?

So what happened from 4+ billion years back till today to make a hidden Pluto ocean possible? Simulations predict as below:

We believe Pluto had a violent history among with some others in solar system. Initially, big collisions drew ultimate shape of the planet and finalized this task. At the same time, planet Pluto was pushed away from gravitational center of solar system. Finally in time, she settled to her new orbit around the Sun. Most probably the moon Charon was the best company through these years.

Pluto elevation map
This Pluto picture is not a map of Pluto oceans. This is only an elevation map, where different colors mean different altitudes. But it looks cool for this article, right?

After the violent times are over, common destiny of rocky planets (which are far enough from their stars) rules the rest. As a result; gravitational effects settle down, rotational forces decrease and the rocks start to cool down.

Since our case is about possibility of a buried ocean, it’s very important how cool we are talking about.

Pluto Ocean – Depends On How Cool Pluto Is

This is where two different results of simulations take place.

In one scenario, planet Pluto does not own enough protection to keep the inner temperature high enough. What we mean by “protection” here is a kind of layer to cover the ocean surface and inhibit cooling it down. Consequently, lack of such shield won’t let her keep the water in liquid form. Considering planets age in this scenario, simulations result with the hypothetical Pluto ocean getting frozen couple of hundred million years back.

A second option according to the researchers could be an insulating layer of gas hydrates among the liquid surface. When simulations ran according to this assumption, the result is charming: Pluto has a subsurface ocean for over a billion years!

Pluto layers in details
A sketch illustrating the hypothetical Pluto ocean and its shield. Source: Kamata S., “Pluto’s Ocean is Capped and Insulated By Gas Hydrates”, Nature Geosciences, May 20, 2019, Link here

What If The Buried Ocean Exists?

Do you feel time to time you don’t get the basic fact on popular science articles? This happens. And we want to avoid such confusions as long as we can:

We are still not 100% sure that an underground Pluto ocean exists. So the new study basically seeks an answer to “How could Pluto have an underworld ocean?” and explicates the possibilites.

But for a second, let’s assume the Pluto ocean is still waving down there.

If we knew it for sure, it could mean a lot: We could verify, or at least better estimate existence of liquid water on other cold and icy planets as well. And what is more important, water could mean life on Pluto in a primitive way.

The life in the way we know depends on several different conveniences. And liquid water is one of the essentials. However, we have some weird examples in the world, where existence of only water and/or methane is enough.

Methane bubbles on Lake Baikal. Image credit: Kristina Makeeva

Similarly, we know Pluto is rich in terms of methane. And the results of calculations show most of the methane seems to be buried beneath the surface. This is where it can meet liquid water!

Consider above and the age of a possible ocean underneath the icy crust. Close your eyes for a moment and imagine swimming in the vast, dark Pluto ocean.

OK, now open your eyes and turn on your flaslights. Would it be a big shocker to confront primitive Plutonian creatures?


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