Pluto Is Full of Water Ice, Probably From the Tears It Cried When We Rejected It

Illustration of Pluto full of water ice

Pluto's heart of ice is even colder than we originally thought

NASA recently revealed that the lonely planet, which we so cruelly voted out of our solar system in 2006, contains far more water ice than scientists initially suspected.

"The new map shows exposed water ice to be considerably more widespread across Pluto's surface than was previously known — an important discovery," NASA said in a statement.

Though the term "water ice" may sound redundant to us Earthlings, it's so named to differentiate it from other ices, such as methane, nitrogen and carbon monoxide, which are also present on Pluto. 

The revelation came from data collected by the New Horizons spacecraft when it flew past Pluto in July. According to NASA, a previous map based on the same data also showed evidence of water ice, but the new map, which is much more detailed, revealed a much fuller picture.

Check out the differences below — the old map is on the left; the new map is on the right:


"In this particular instance, it's more of a clue as to what's going on on Pluto, and more information to help us unravel the mystery of what is turning out to be a really complex and unusual and strange planet," David Grinspoon, an astrobiologist and senior scientist at the Planetary Science Institute, told Mic. ("I can't help but call it a planet," he added, laughing.)

Water ice is an important part of Pluto's makeup, as it's considered the dwarf planet's "crustal bedrock," which NASA describes as "the canvas on which its more volatile ices paint their seasonally changing patterns." 

The previous map wasn't quite as clear because much of the water ice was concealed by methane ice; this time, by focusing on all known ices together, researchers were essentially able to tone down the non-water ices, thereby allowing them to observe much more of the good stuff.

"Water ice on Pluto is basically the bedrock. It's like finding deposits of granite on Earth," Grinspoon said. "It's more than telling us one specific thing — it's giving us a great diagnostic tool. There'll be a lot of PhD theses written [about this]." 

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So, why does this matter? We've known for a while that Pluto was an icy wonderland — it is the possible home of ice volcanos, after all. 

But water is considered one of the key features of habitable planets, and scientists are always on the lookout for those. It's the eternal question: Are we all alone in this great big universe? (Spoiler alert: Probably not, but it's complicated.)

"We're very interested in the water in the universe because we are water in a certain sense," Grinspoon told Mic. "We're very tuned in to where in the universe water is and what it's doing, because it's connected to these larger questions of origin and existence."

This isn't to say that Pluto can sustain life, but Grinspoon said he's "tantalized" by the prospect.

"It's active. It's fresh. There's sources of activity, and possibly sources of heat, that we don't understand. And you combine that with the presence of water, and you have to go, well, wait a minute, what are the requirements of life?" he said. New discoveries like this, besides being cool to think about, are small yet important pieces of the larger space puzzle.

"It doesn't tell me, aha, there's life on Pluto!" Grinspoon added. "But it tells me it's the kind of environment that we astrobiologists are interested in learning more about."