Although nearly a decade has passed since NASA’s New Horizons spacecraft visited Pluto, the dwarf planet is still revealing itself as a surprisingly complex world.
Scientists studying spacecraft data for an unusual crater near a bright, heart-shaped area on Pluto called… Sputnik Planitia They say they may have found a supervolcano that likely erupted only a few million years ago. That may seem like an incredibly long time ago, but in cosmic terms, it’s very recent. For context, the solar system is more than 4.5 billion years old.
But instead of molten rock erupting from Earth’s volcanoes, the 44-kilometre-wide Kyladze crater appears to contain It spewed icy lava On the surface of Pluto in a process known as cryovolcanism. This process, which also occurs on the moons of the gas giants in our solar system and likely created other mysterious landforms on Pluto, is thought to have forced water from Earth’s hidden subsurface ocean onto its surface, reshaping it over millions of years.
Volcanoes require some kind of heat source to erupt, so recent activity on Pluto suggests there is more heat left in the dwarf planet’s interior than previously thought.
Related: Cracks on Pluto’s moon Charon may be evidence of a frozen subsurface ocean
The researchers analyzed images taken by New Horizons of the Kiladze crater, which is located northeast of Sputnik Planitia. While the crater initially appeared similar to one left by meteorite impacts, it appeared to be missing a central peak expected for such geological phenomena. It also appeared to be slightly elongated, consistent with movements caused by tectonic forces from within Pluto, according to the researchers. New studywhich has not yet been peer-reviewed.
Most of Pluto’s surface is covered in methane and nitrogen ice, so “the tell-tale sign that Kyladze is different” from the rest of Pluto’s surface is the strong presence of water ice around the crater, says the study’s lead author. Dale CruikshankA professor at the University of Central Florida told Space.com. “Water ice stands out clearly from the methane ice that covers much of the planet’s surface.”
Pluto’s axis is tilted at a sharp angle of 120 degrees, meaning it rotates almost on its side, causing dramatic changes in climate as it orbits the sun. As a result, the methane ice sublimates into a mist of hydrocarbons in the dwarf planet’s atmosphere, some of which falls as snow and covers its surface.
Over the 4.6 billion-year lifespan of Pluto, scientists estimate that this layer of methane ice must have been at least 14 meters (46 feet) thick. “Even a centimeter or two of this organic smog would mask the spectral signature of water ice that we observe,” Cruickshank said.
Such a layer could have formed in just three million years. This led Cruickshank and his team to conclude that Kiladze was “alive” only a few million years ago.
Scientists don’t fully understand how cryovolcanism works on Pluto. The world is so small that it has lost all heat since its formation long ago. One possibility is that the dwarf planet has radioactive elements in its core that release heat as it decays, although previous research has suggested this There may not be enough Of these elements to provide energy to Pluto.
Whatever the source of the heat, something seems to be preventing the ocean beneath Pluto’s surface from freezing.
“As the planet cools, it is plausible that pockets of liquid water are left behind, and perhaps water eruptions on the surface flow into those pockets,” Cruickshank said.
But the researcher added: “We don’t know.”
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