Pluto may be hiding vast ancient OCEAN that formed 4.5billion years ago – and is slowly freezing
PLUTO may be hiding a vast ancient, ocean that formed 4.5billion years ago.
It’s now believed that Pluto may have had a “hot start”, allowing a huge sea to form – which is slowly freezing over time.
The dwarf planet is distant from the sun, making it extremely frosty.
It can be as cold as -240C, which has allowed an enormous icy crust to form across the planet’s surface.
Previously, experts thought that Pluto began as a frozen ball of ice and rock, ice melting to form a subsurface ocean.
But new research suggests that the planet started off warm with an early ocean – freezing over the aeons.
The discovery was made thanks to images from Nasa spacecraft.
“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 Francis Nimmo, of the University of California 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.”
Water expands when it freezes, and contracts when it melts.
This means that we see different surface features on planets, depending on what’s happening to water.
And that provides key clues to Pluto’s make-up.
“If it started cold and the ice melted internally, Pluto would have contracted and we should see compression features on its surface,” said USCS’s Carver Bierson.
“Whereas if it started hot, it should have expanded as the ocean froze, and we should see extension features on the surface.
“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.”
Researchers think that if Pluto formed over a period of less than 30,000 years, then it would have started out hot.
However, if it took a few million years, a hot start is less likely – but still possible, if “large impactors” buried their energy deep below the surface.
“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.”
Pluto – the key facts
Here's what you need to know, according to Nasa...
- Pluto measures roughly 1,400 miles across, around half the width of the USA
- It orbits the Sun around 3.6billion miles away on average – 40 times farther than Earth
- It takes 248 Earth years for Pluto to orbit the Sun – with each day lasting 153 hours
- Pluto has a thin atmosphere of nitrogen, methane and carbon monoxide
- Unlike the eight “proper” planets in our Solar System, Pluto is officially classified as a dwarf planet
- Pluto has five moons, the biggest of which is called Charon
- Nasa’s New Horizons is the only spacecraft to visit Pluto, passing by in July 2015
Bierson added: “Even in this cold environment so far from the sun, all these worlds might have formed fast and hot, with liquid oceans.”
Hidden oceans on other worlds are of huge interest to scientists.
Pluto’s surface is far too cold to sustain life as we know it.
Oceans can harbour life, and sub-surface seas could be protected from destructive forces – potentially allowing alien lifeforms to thrive.
This research was published in the Nature Geoscience journal.
In other news, stunning images of a recent Starlink launch reveal a magical “rocket nebula” phenomenon.
Scientists think they’ve found a potentially habitable exoplanet.
Elon Musk has said SpaceX’s Starship rocket, which he hopes will put Americans on Mars, is now the company’s “top priority”.
And, Nasa has revealed the design of a moon lander that could take astronauts back to the lunar surface by 2024.
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