This is the best image we've ever seen of Pluto's largest moon - and it has stunned scientists

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After hours of tense waiting, NASA finally released the first images its New Horizons spacecraft took during its historic flyby of Pluto and its moons.

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That full collection of images will trickle in over the next year or so, but NASA's first release included some unprecedented views of Pluto's largest moon Charon (pronounced Shar-on, according to its discoverer):

nh charon ORIGINAL IMAGE

NASA-JHUAPL-SwRI

Remarkable new details of Pluto's largest moon Charon are revealed in this image from New Horizons' Long Range Reconnaissance Imager (LORRI), taken late on July 13, 2015 from a distance of 289,000 miles (466,000 kilometers).

"Charon just blew our socks off," Cathy Olkin, New Horizons deputy project scientist, said during a NASA press conference Wednesday. "The team has just been abuzz, 'look at this, look at that, that's amazing!'"

We've known about Charon since the 1970s - well before the New Horizons mission. But the best images we had of it were fuzzy blobs, like the one below, which the Hubble space telescope captured in 1998. Charon is the top right object:

pluto and charon 1998

NASA

The New Horizons team expected to find a cold, dead, and cratered satellite of Pluto. But the mission's principle investigator Alan Stern shared some surprising news:

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"Charon has been active [recently], and there are mountains in the Kuiper belt," Stern said during the press conference.

Charon is the same size as other objects in the Kuiper Belt, and scientists always thought these objects were just "candy-coated lumps of ice," New Horizons scientist John Spencer said. Now they're entirely questioning that assumption.

Olkin explained that the smooth band that runs from the northeast part of Charon to the southwest corner suggests that the moon might be geologically active and resurfacing the world.

The canyon in the top right corner of Charon is four to six miles deep, Olkin said, and there are cliffs that extend about 600 miles across.

Researchers are also learning a lot more about Charon's mysteriously dark-colored north pole that they have nicknamed "Mordor."

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"We think that the dark coloring could perhaps be a thin veneer," Olkin said, as evidenced by bright-white impact craters.

Charon has already blown away scientists, and it will certainly continue to do so as we slowly download more data from New Horizons.

"Pluto did not disappoint. I can add that Charon did not disappoint either," Olkin said.

But that wasn't all we learned about Pluto's moons. In the last decade we've discovered four new ones orbiting Pluto. We got a glimpse of two - Nix and Hydra - in this image taken by Hubble in 2006:

pluto, charon, nix and hydra 2006

NASA

"Pluto and Charon are going to steal the day today, but let's not forget that Pluto has four small moons," Hal Weaver, project scientist for New Horizons, said during the NASA press conference.

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And we got our first-ever image of one of them - Hydra. It's not as clear as the Charon photo, since it was farther away from the New Horizons spacecraft:

nh hydra_1  ORIGINAL IMAGE

NASA-JHUAPL-SwRI

Image of Pluto's moon Hydra taken from New Horizons on July 14th, 2014. Hydra was approximately 400,000 miles away from New Horizons when the image was acquired.

But there's a trove of surprising information hidden in the pixelated blob.

"The surface of Hydra is surprisingly large - about 45% percent of sunlight gets reflected away," Weaver said. "The surface is composed primarily of water ice. That's the only way to get it that bright. And that's cool."