By Irene Klotz
LAUREL, Md. (Reuters) - The first close-up views of Pluto show mountains made of ice and a surprisingly young, crater-free surface, scientists with NASA's New Horizons mission said on Wednesday.
The results are the first since the piano-sized spacecraft capped a 3 billion mile (4.82 billion km), 9-1/2-year-long journey to pass within 7,800 miles (12,550 km) of Pluto on Tuesday.
New Horizons is now heading deeper into the Kuiper Belt, a region of the solar system beyond Neptune that is filled with thousands of Pluto-like ice-and-rock worlds believed to be remnants from the formation of the solar system, some 4.6 billion years ago.
Scientists do not know how Pluto formed such big mountains, the tallest of which juts almost 11,000 feet (3,350 meters) off the ground, nearly as high as the Canadian Rockies.
Another puzzle is why Pluto has such a young face. The icy body, which is smaller than Earth's moon, should be pocked with impact craters, the result of Kuiper Belt rocks and boulders raining down over the eons.
Instead, New Horizons revealed that the surface of Pluto has somehow been refreshed, activity that may be tied to an underground ocean, ice volcanoes or other geologic phenomenon that gives off heat.
Scientists believe Pluto's mountains likely formed within the last 100 million years, a relative blink compared to the age of the solar system.
New Horizon's first close-up, which covered a patch of ground about 150 miles (241 km) near Pluto's rugged equatorial region, even has scientists wondering if the icy world is still geologically active.
"Pluto has so much diversity. We're seeing so many different features ... there’s nothing like it," New Horizons scientist Cathy Olkin told reporters at John Hopkins University Applied Physic Lab where the mission control center is located.
Another surprise was Pluto's primary moon, Charon, which was believed to be geologically dead. Instead, New Horizons found troughs, cliffs and giant canyons - all evidence of internal processes.
"Charon just blew our socks off," said Olkin.
So far only a fraction of the thousands of pictures and science measurements collected by New Horizons during its traverse through the Pluto system have been relayed. The data will be transmitted back to Earth over the next 16 months.
"I don't think any one of us could have imagined that it was this good of a toy store," said New Horizons' lead scientist Alan Stern.