It's official. Pluto just keeps getting weirder.

Last July the space probe New Horizons made humanity's first flyby of Pluto and glimpsed a world stranger and far more complex than anyone had imagined. Rather than dull and dead, the dwarf planet is smattered with odd geographical features and, somehow, ongoing geological activity. Today, we've learned even more about this weird world and its moons from the scientists trying to make sense of the discovery, who published the first detailed analysis of Pluto's landscape, atmosphere, moons, chemistry, and its surprising interaction with solar wind. Outlined in five new papers published in the journal Science, scientists have their first hints at the origin of mysteriously complex landscape.

"It turned out to be really crazy."

"This was the human race's first visit to a planetary body living out in the Kuiper Belt, [the region beyond Neptune], so it's an entirely new class of world," says Bill McKinnon, an astrophysicist at the University of Washington in St. Louis and deputy lead of the New Horizons Geology, Geophysics and Imaging team. "It turned out to be really crazy."

Pluto and its satellites H.A. Weaver et. al.

Alien Ice

McKinnon co-authored the paper in today's batch that's an overview of the menagerie of geographical features found on Pluto. As McKinnon will tell you, there are a lot.

"Pluto has possible cryovolcanoes, cratered plains, crater-free frozen planes, rugged plains, etched and pitted canyons, glacial erosion, glacially suspended terrain, upright blades of ice, mountain ridges, motion flow-lines around obstacles, wall-to-wall craters covered with some red material that may be methane ice baked by radiation, broken assemblages of water-ice crust assembled together like logs in a jam, big bands of land that are tracked with what looks like the arms of saguaro cactus," McKinnon says. "Should I keep going?"

He says these features place Pluto, once considered just a lonely ice-ball in the dark, on par with Mars (and second only to Earth) in terms of geological complexity. So what's causing Pluto's wacky, varied landscape?

New Horizons has shown that Pluto is continually shaped and carved by ices—not just water ice, "but some quite exotic," says McKinnon. Carbon dioxide ice, methane ice, and different nitrogen ices are present. These various ices have a wide range of melting, freezing, and evaporating temperatures. The way that they move about in the extreme cold at different layers of Pluto's surface —through melting, slipping, glaciating, and chemically transitioning straight from solid to gas—is an alien process to us, but one that cam at least partially explain why Pluto looks the way it does, and keeps changing.

"We're only just now learning how these different ices work at these extremely low temperatures," says Fran Bagenal, an astrophysicist and New Horizons' team leader at the University of Colorado. "This is a world radically different than anything we've seen before, so how these extremely cold ices can flow or not flow, or, say, form big chunky surfaces that act like rock, it's all new."

"Pluto has possible cryovolcanoes, cratered plains, rugged plains, etched and pitted canyons, glacial erosion, glacially suspended terrain, upright blades of ice... Should I keep going?"

Unknown Engine

Not all of Pluto's wild landscape can be described by shifting ices, McKinnon says. Something else gives Pluto the energy to form features that could be cryovolcanoes—volcanoes that spew cold liquids and snows. That same something is keeping the entire dwarf planet active enough that it effectively erases new craters within10 million years. What that is, "we just don't know," McKinnon, "it's just that nature has figured out ways of doing surprising things with icy worlds that we just didn't anticipate, and can't yet explain."

Hints may lie in today's exceptional new history of Charon, another of the new studies. As McKinnon explains, Charon has essentially two planes on its surface. One is craggy and covered with old craters, while the other is newly smooth. Scientists now believe that Charon was once holding in a liquid ocean (but not a water ocean), which at some point froze and punctured Charon like a water balloon. As that liquid spewed out, its wiped part of the moon's surface smooth with a fresh glaze of ice—which explains Charon's duality, its jagged and smooth halves.

Mysteries Galore

Today brought another Pluto surprise: The atmosphere is far, far smaller than anticipated. "We were expecting an atmosphere about 100 times larger than we ended up seeing," says Bagenal.

H.A. Weaver et. al.

Scientists now know that this size disparity is because the atmosphere is "much colder and so much more more tightly confined to Pluto," she says. Originally the researchers thought that because of Pluto's weak gravity, the atmosphere would easily heat up and expand due to oncoming solar wind, and be rapidly whisked away. That was not the case. But why the atmosphere is so cold, and clings so tightly, is anyone's guess. Yet another mystery.

Bagenal also led a research group which studied Pluto's interaction with solar wind. Data on this was collected as New Horizon flew behind Pluto—essentially in the minor planet's wake as Pluto eclipsed the sun. Because the wispy atmosphere was far smaller than anticipated, the research group discovered that Pluto barely interacts with solar wind (and other energetic particles that blast from the Sun).

The New Horizons probe also carried a dust measuring instrument meant to collect samples during the Pluto flyby. Today Bagenal reports that in the five days surrounding the fly-by New Horizons reported one dust particle. One. So, it's pretty clean out there.

Both Bagenal and McKinnon are emphatic that Pluto still holds many more secrets and discoveries—indeed, the New Horizons probe is still beaming back information from its fly-by. "And this is just a taste of what we can possibly find out further in our solar system and the universe," says McKinnon.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io