Study Suggests Pluto Started Out With Liquid Oceans

Related Articles

Related Articles

A new study suggests that Pluto and other large Kuiper belt objects started out with liquid oceans which have been slowly freezing over time.

The accretion of new material during Pluto’s formation may have generated enough heat to create a liquid ocean that has persisted beneath an icy crust to the present day, despite the dwarf planet’s orbit far from the sun in the cold outer reaches of the solar system.

This “hot start” scenario, presented in a paper published June 22 in Nature Geoscience, contrasts with the traditional view of Pluto’s origins as a ball of frozen ice and rock in which radioactive decay could have eventually generated enough heat to melt the ice and form a subsurface ocean.

“For a long time people have thought about the thermal evolution of Pluto and the ability of an ocean to survive to the present day,” said coauthor Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz. “Now that we have images of Pluto’s surface from NASA’s New Horizons mission, we can compare what we see with the predictions of different thermal evolution models.”

Because water expands when it freezes and contracts when it melts, the hot-start and cold-start scenarios have different implications for the tectonics and resulting surface features of Pluto, explained first author and UCSC graduate student Carver Bierson.

“If it started cold and the ice melted internally, Pluto would have contracted and we should see compression features on its surface, whereas if it started hot it should have expanded as the ocean froze and we should see extension features on the surface,” Bierson said. “We see lots of evidence of expansion, but we don’t see any evidence of compression, so the observations are more consistent with Pluto starting with a liquid ocean.”


Subscribe to more articles like this by following our Google Discovery feed - Click the follow button on your desktop or the star button on mobile. Subscribe

The thermal and tectonic evolution of a cold-start Pluto is actually a bit complicated, because after an initial period of gradual melting the subsurface ocean would begin to refreeze. So compression of the surface would occur early on, followed by more recent extension. With a hot start, extension would occur throughout Pluto’s history.

“The oldest surface features on Pluto are harder to figure out, but it looks like there was both ancient and modern extension of the surface,” Nimmo said.

The next question was whether enough energy was available to give Pluto a hot start. The two main energy sources would be heat released by the decay of radioactive elements in the rock and gravitational energy released as new material bombarded the surface of the growing protoplanet.

Bierson’s calculations showed that if all of the gravitational energy was retained as heat, it would inevitably create an initial liquid ocean. In practice, however, much of that energy would radiate away from the surface, especially if the accretion of new material occurred slowly.

“How Pluto was put together in the first place matters a lot for its thermal evolution,” Nimmo said. “If it builds up too slowly, the hot material at the surface radiates energy into space, but if it builds up fast enough the heat gets trapped inside.”

The researchers calculated that if Pluto formed over a period of less that 30,000 years, then it would have started out hot. If, instead, accretion took place over a few million years, a hot start would only be possible if large impactors buried their energy deep beneath the surface.

The new findings imply that other large Kuiper belt objects probably also started out hot and could have had early oceans. These oceans could persist to the present day in the largest objects, such as the dwarf planets Eris and Makemake.

“Even in this cold environment so far from the sun, all these worlds might have formed fast and hot, with liquid oceans,” Bierson said.

In addition to Bierson and Nimmo, the paper was coauthored by Alan Stern at the Southwest Research Institute, the principal investigator of the New Horizons mission.

UNIVERSITY OF CALIFORNIA – SANTA CRUZ

- Advertisement -

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Study Suggests Pluto Started Out With Liquid Oceans

A new study suggests that Pluto and other large Kuiper belt objects started out with liquid oceans which have been slowly freezing over time.

Scientists provide new explanation for the far side of the Moon’s strange asymmetry

The Earth‐Moon system's history remains mysterious. Scientists believe the two formed when a Mars‐sized body collided with the proto‐Earth.

300-million-year-old fish resembles a sturgeon but took a different evolutionary path

Sturgeon, a long-lived, bottom-dwelling fish, are often described as "living fossils," owing to the fact that their form has remained relatively constant, despite hundreds of millions of years of evolution.

Study Suggests Cosmic Body Destroyed Ancient Village 12,800 Years Ago

A study submitted in Scientific Reports suggests that the debris stream from a short-period comet may have destroyed the archaeological site of Tell Abu Hureyra.

Archaeologists Find Large Neolithic Structure at Durrington Walls

Archaeologists from the University of Bradford have announced the discovery of a large prehistoric site at Durrington Walls near Stonehenge in England.

Cliff Villages of Bandiagara – The Land of the Dogons

The cliffs of Bandiagara is a large geological escarpment rising above the surrounding flatlands in Mali that contains various archaeological sites and 289 ancient settlements.

Study Suggests the Mystery of The Lost Colony of Roanoke Solved

The Roanoke Colony refers to two colonisation attempts by Sir Walter Raleigh to establish a permanent English settlement in North America.

Drones Map High Plateaus Basin in Moroccan Atlas to Understand Human Evolution

Researchers from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) have been using drones to create high-resolution aerial images and topographies to compile maps of the High Plateaus Basin in Moroccan Atlas.

The Kerguelen Oceanic Plateau Sheds Light on the Formation of Continents

How did the continents form? Although to a certain extent this remains an open question, the oceanic plateau of the Kerguelen Islands may well provide part of the answer, according to a French-Australian team led by the Géosciences Environnement Toulouse laboratory.

Ancient Societies Hold Lessons for Modern Cities

Today's modern cities, from Denver to Dubai, could learn a thing or two from the ancient Pueblo communities that once stretched across the southwestern United States. For starters, the more people live together, the better the living standards.

Popular stories