NASA scientists announced on Wednesday that the New Horizons interplanetary space probe had captured the first close-up high-resolution photos of Pluto in history. The probe's first close-up image covers around 150 miles (241 kilometers) near the dwarf planet's equator, and has researchers wondering if the frigid far-off world could still be geologically active.

The pictures show large ice mountains, the tallest of which peaks at around 11,000 feet (3,350 meters), almost as high as the Canadian Rocky Mountains.

A geological puzzle

What has really piqued scientific curiosity, however, is the relatively young, crater-free face of Pluto. As a result of its proximity to the Kuiper Belt, a stretch of rocks and asteroids beyond Neptune which is 20 times wider and 20 to 200 times as massive as the asteroid belt between Mars and Jupiter, Pluto should have a face scarred by impact craters.

NASA hypothesized that the surface of the planet must somehow have been refreshed, either through ice volcanoes, an underground ocean, or other geological activity that gives off heat.

"Pluto has so much diversity. We're seeing so many different features ... there's nothing like it," New Horizons scientist Cathy Olkin told the press.

Another surprise was found on the surface of Charon, Pluto's primary moon, which was filled with great valleys, cliffs, and canyons - evidence that is it not geologically dead as previously thought.

"Charon just blew our socks off," said Olkin.

Now that New Horizons has completed its 3 billion mile (4.82 billion kilometer), nine and a half year journey out to the edge of the solar system, it will continue on deeper into the Kuiper Belt to investigate what scientists believe to be remnants from the formation of the solar system around 4.6 billion years ago.

es/msh (AFP, Reuters)