Watch: NASA New Horizons Video of Pluto Shows Never Before Seen Images of Icy Terrain and Miles-High Mountains

Pluto, with a heart-shaped region on its surface, is pictured in this image from the Long Range Reconnaissance Imager aboard NASA's New Horizons spacecraft, taken July 13, 2015, when the spacecraft was 476,000 miles from the surface. NASA/APL/SwRI via Getty

NASA's New Horizons mission has been instrumental in building knowledge about Pluto. The $700 million mission, which launched in 2006, conducted the first-ever flyby of the dwarf planet in 2015. The novel images of Pluto revealed much about its surface and even concluded that it was slightly larger than previously thought.

Now the American space agency has released a never before seen animation to celebrate the two-year anniversary of the flyby. The video, published Friday, was made with data and images sent back from the mission. It shows rocky mountain ranges and plains of ice on the planet's surface.

NEW! Enjoy this #Pluto flyby video, made with data from our historic #PlutoFlyby.

— NASA New Horizons (@NASANewHorizons) July 14, 2017

The mission has revolutionized the scientific community's understanding of Pluto. The 2015 flyby collected more than 1,200 images—including a striking image of a heart-shaped formation on the dwarf planet's surface—and 10 gigabits of data. It also revealed mountains that jut out up to 2 miles high and a wide variety of color variations, which could indicate a complex geology and climate. And it showed that Pluto is surrounded by a blueish atmospheric haze and that an ocean of liquid water may be flowing under the planet's icy surface.

The flyby found that all five of Pluto's moons are the same age and thus were likely formed in the same impact incident between Pluto and another celestial object billions of years ago. It also provided detailed images of Charon, the largest of Pluto's five moons, which has a reddish coloring and a dark area near the moon's north pole—which was dubbed Mordor, after the dark region in J.R.R. Tolkien's The Lord of the Rings.

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"I think the most surprising thing [to come out of New Horizons] is how complex that little planet is," the mission's principal investigator Alan Stern of the Southwest Research Institute in Colorado, told on the flyby's two-year anniversary. "It outstripped everyone's expectations, and I am certain that we're going to need an orbiter follow-up to make sense of Pluto."

Pluto was long considered to be the ninth planet in the solar system. But after years of debate, the International Astronomical Union demoted it to the rank of a dwarf planet in 2006, reducing the total number of planets in the solar system to eight. Some astronomers believe there may be a mysterious Planet Nine in the outer reaches of the solar system, but its existence has not yet been confirmed.

10-9-15 Pluto Blue Skies
Pluto’s haze layer shows its blue color in this picture taken by the Ralph instrument on the New Horizons spacecraft. NASA/JHUAPL/SwRI

The New Horizons probe remains on an extended mission into the Kuiper Belt, a distant region made up of icy celestial bodies, including dwarf planets like Pluto and comets. Little is known about the Kuiper Belt since its existence was predicted by Dutch-American astronomer Gerard Kuiper in 1973, and New Horizons is expected to go far into the region, at least a billion miles beyond the orbit of Neptune, the planet furthest from the sun in our solar system.

The probe is due to complete a flyby of a small celestial object, called 2014 MU69, on January 1, 2019. The icy object lies about 1 billion miles beyond Pluto.