Pluto’s Radioactive Volcanoes Spewed Icy Slurry — Mystery Mountains Are ‘Definitely Weird’

Pluto gets weirder every day. NASA has just uncovered what looks like volcanoes on the distant planet’s surface — ones that once spewed an icy slurry fueled by radioactivity.

However, NASA isn’t shouting from the rooftops that they’ve found icy volcanoes on Pluto just yet. Instead, they are tentatively suggesting that the formation discovered by the New Horizons probe last July resemble volcanoes and for now, that’s their best and only theory, Scientific American reported.

So far, NASA has discovered two of them on Pluto. The peaks are being called Wright Mons and is two miles high, and Piccard Mons, which is 3.5 miles high, Smithsonian reported. And when the New Horizons flew by Pluto this summer, it almost missed them.

Icy volcanoes may lie on the southern rim of #Pluto's frozen heart. https://t.co/jo23UNiIFe pic.twitter.com/jBJJGM1Tm9

— SPACE.com (@SPACEdotcom) November 10, 2015

Piccard sits in a twilight zone at the day-night border on the planet and was hard to spot. Wright, luckily, is dappled with light on its slopes, a clue that the icy volcanoes are older than the surrounding area, Smithsonian explained. Both were found on the southern edge of Pluto’s so-called “heart,” a plain now called Sputnik Planum.

Both icy volcanoes are 100 miles wide — scientists spied depressions at the peaks. Both resemble shield volcanoes, like Hawaii here on Earth and Olympus Mons on Mars. Both icy volcanoes on Pluto once spewed a “slurry of ices” onto the surface of the planet, but haven’t erupted in quite some time.

Science has never seen anything like them, said NASA scientist Oliver White.

“We see nothing of this scale with a summit depression anywhere else in the outer solar system. Whatever they are, they are definitely weird, and volcanoes may be the least weird hypothesis at the moment.”

So what makes them so weird? The universe has a few examples of cryovolcanism, but Pluto’s icy volcanoes are very different, he told Space.com.

Something on Saturn’s moon, Enceladus, churns out icy material on its southern pole from fissures in the ground, not a mountain. The planet’s other moon, Titan, may have cryovolcanoes, but they’ve only been spied on radar and no one can agree on what they are. Neptune’s moon, Triton, has icy volcanoes sustained by Neptune’s gravitational pull, which flexes the moon to create frictional heat.

NASA's New Horizons mission spots 2 mountains on Pluto that may be icy volcanoes! https://t.co/sHQZHXo1ew #DPS15 pic.twitter.com/tSEObtKYxy

— nature (@Nature) November 10, 2015

But Pluto’s icy volcanoes are a whole new thing, but they’re still mysterious. Not only is NASA not ready to call them volcanoes, but they don’t know when they were last active or what made them erupt. They have a theory, of course.

Pluto is pretty active geologically, which suggests an internal heat source. This source is likely from the radioactive decay left over from the birth of the planet 4.5 billion years ago. This material, stored deep inside Pluto, may be hot enough to instigate an eruption. But don’t think of Earth’s volcanoes when you imagine this awesome sight — Pluto’s icy versions wouldn’t need that much energy to explode, because the planet’s ices are quite unstable.

If scientists have, indeed, found icy volcanoes on Pluto, this hints that the planet is covered in volatile ice that flows at the surface and below it. And the presence of two formations provides a final, and tantalizing, idea: there may be more.

White said that a larger field of icy volcanoes may populate Pluto, but weren’t captured by the probe last summer. So, for now, there’s no way to check that assumption.

“We’ll have to go back in a hundred years and see.”

NASA has also learned that Pluto is littered with tall scarps and expansion features that suggest that the planet has an ocean beneath its surface that expands when it freezes, Smithsonian added. The atmosphere on the planet is also quite compact and being peeled off by solar radiation a thousand times slower than thought. And Pluto’s moons — Styx, Nix, Kerberos, and Hydra — are titled and spinning like mad, so fast that Hydra’s day is only 10 hours long.

[Photo By NASA / Getty Images]