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(CNN)Images of Pluto captured by NASA's New Horizons mission have revealed a new surprise: ice volcanoes.
The spacecraft performed a flyby of the dwarf planet and its moons in July 2015, and the insights gathered then are still rewriting nearly everything scientists understand about Pluto.
Pluto was relegated to dwarf planet status in 2006 when the International Astronomical Union created a new definition for planets, and Pluto didn't fit the criteria.
The dwarf planet exists on the edge of our solar system in the Kuiper Belt, and it's the larger of the many frozen objects there orbiting far from the sun. The icy world, which has an average temperature of negative 387 degrees Fahrenheit (negative 232 degrees Celsius), is home to mountains, valleys, glaciers, plains and craters. If you were to stand on the surface, you would see blue skies with red snow.
A new photo analysis showed a bumpy region on Pluto that doesn't look like any other part of the small world -- or the rest of our cosmic neighborhood.
"We found a field of very large icy volcanoes that look nothing like anything else we have seen in the solar system," said study author Kelsi Singer, senior research scientist at the Southwest Research Institute in Boulder, Colorado.
A study detailing the findings published Tuesday in the journal Nature Communications.
The region is located southwest of the Sputnik Planitia ice sheet, which covers an ancient impact basin stretching 621 miles (1,000 kilometers) across. Largely made of bumpy water ice, it's filled with volcanic domes. Two of the largest are known as Wright Mons and Piccard Mons.
Wright Mons is about 13,123 to 16,404 feet (4 to 5 kilometers) tall and spans 93 miles (150 kilometers), while Piccard Mons reaches about feet 22,965 feet (7 kilometers) high and is 139 miles (225 kilometers) wide.
Wright Mons is considered to be similar in volume to the Mauna Loa volcano in Hawaii, which is one of the biggest volcanoes on Earth.
Some of the domes observed in the images merge together to form even bigger mountains, Singer said. But what could have created them? Ice volcanoes.
Ice volcanoes have been observed elsewhere in our solar system. They move material from the subsurface up to the surface and create new terrain. In this case, it was water that quickly became ice once it reached the frigid temperatures of Pluto's surface.
"The way these features look is very different than any volcanoes across the solar system, either icy examples or rocky volcanoes," Singer said ."They formed as mountains, but there is no caldera at the top, and they have large bumps all over them."
While Pluto has a rocky core, scientists have long believed that the planet lacked much interior heating, which is needed to spur volcanism. To create the region Singer and her team studied, there would have been several eruption sites.
The research team also noted that the area doesn't have any impact craters, which can be seen across Pluto's surface, which suggests that the ice volcanoes were active relatively recently -- and that Pluto's interior has more residual heat than expected, Singer said.
"This means Pluto has more internal heat than we thought it would, which means we don't fully understand how planetary bodies work," she said.