The biggest discovery in new images of Pluto is what scientists didn't see

New Horizons Probe Reveals Pluto Has Ice Mountains

NASA's New Horizons team has just revealed the most detailed images of Pluto yet, and the space agency is ecstatic about what it has seen: a smooth, young, and active surface on what had been thought to be an old, battered ball of ice.

The New Horizons spacecraft took the following images on Tuesday, almost a decade after the mission began, at a distance of 47,800 miles. The spacecraft's closest approach was within 7,800 miles.

The latest close-up image reveals a young, pointy mountain range that is about 11,000 feet high. Members of the New Horizons team believe this region, which covers less than 1% of Pluto's surface, is no more than 100 million years old — a youngster in the 4.56-billion-year-old solar system.

What's more: The mountain ranges are probably still growing.

nh plutosurface

"This is one of the youngest surfaces we've ever seen in the solar system," Jeff Moore, a member of the New Horizons geology, geophysics, and imaging team, said in a NASA press release.

Scientists expected Pluto's surface to be heavily marked with craters from billions of years of pummeling by space rocks. Instead the team discovered the dwarf planet's surface — or at least the part seen so far — to be relatively free of craters.

"We have not yet found a single impact crater on this image," John Spencer, one of the co-investigators on the New Horizons team, said in a news conference. "This means that Pluto has a very young surface."

But that doesn't mean it's smooth. The mountain range is about as tall as Earth's Rocky Mountains.

Those are signs the dwarf planet is geologically active. Moore, Spencer, and the researchers can't explain where that activity is coming from, because Pluto doesn't have the push and pull of gravity from a larger planet to heat it and keep it active.

This tells us some other type of process must be making Pluto's surface geologically active.

One theory is that radiation in the planet keeps it warm and active.

"We know there's radioactive material in Pluto and Charon," Spencer said, referring to Pluto's largest moon, "as the same as bodies in our solar system. This may be telling us that even in small bodies, if they're icy, radioactive heat is enough to produce [geologic] activity."

Click through to see photos from the flyby:

25 PHOTOS
New Horizons' Pluto mission
See Gallery
The biggest discovery in new images of Pluto is what scientists didn't see
IN SPACE - JULY 15: In this handout provided by the National Aeronautics and Space Administration (NASA), Backlit by the sun, Plutos atmosphere rings its silhouette like a luminous halo in this image taken by NASAs New Horizons spacecraft around midnight EDT on July 15, and released July 23, 2015. New Horizons passed by Pluto July 14, closing to a distance of about 7,800 miles (12,500 kilometers). This global portrait of the atmosphere was captured when the spacecraft was about 1.25 million miles (2 million kilometers) from Pluto and shows structures as small as 12 miles across The 1,050-pound piano sized probe was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, (Photo by NASA/JHUAPL/SwRI via Getty Images)
IN SPACE - JULY 14: In this handout provided by the National Aeronautics and Space Administration (NASA), A newly discovered mountain range lies near the southwestern margin of Plutos Tombaugh Regio (Tombaugh Region), situated between bright, icy plains and dark, heavily-cratered terrain. This image was acquired by New Horizons Long Range Reconnaissance Imager (LORRI) on July 14, 2015 from a distance of 48,000 miles (77,000 kilometers) and sent back to Earth on July 20, 2015. Features as small as a half-mile (1 kilometer) across are visible.. The 1,050-pound piano sized probe was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, (Photo by NASA/JHUAPL/SwRI via Getty Images)

Pluto's largest moon Charon

Image Credit: NASA-JHUAPL-SwRI

This July 13, 2015, image of Pluto and Charon is presented in false colors to make differences in surface material and features easy to see. It was obtained by the Ralph instrument on NASA's New Horizons spacecraft, using three filters to obtain color information, which is exaggerated in the image.  These are not the actual colors of Pluto and Charon, and the apparent distance between the two bodies has been reduced for this side-by-side view.

Image Credit: NASA/APL/SwRI

One of the final images taken before New Horizons made its closest approach to Pluto on 14 July 2015. (Photo via NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute)
LAUREL, MD - JULY 14: In this handout provided by the National Aeronautics and Space Administration (NASA), Alice Bowman New Horizons mission operations manager, Johns Hopkins University Applied Physics Laboratory (APL), left, New Horizons Principal Investigator Alan Stern of Southwest Research Institute (SwRI), Boulder, CO., and NASA Associate Administrator for the Science Mission Directorate John Grunsfeld unveil the last and sharpest  image of Pluto captured before closest approach of the New Horizons spacecraft during a media briefing moderated by NASA Senior Public Affairs Officer Dwayne Brown, right, Tuesday, July 14, 2015 at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. New Horizons spacecraft is nearing its July 14 fly-by when it will close to a distance of about 7,800 miles (12,500 kilometers). The 1,050-pound piano sized probe, which was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, is traveling 30,800 mph as it approaches. (Photo by Bill Ingalls/NASA via Getty Images)
IN SPACE - JULY 11: In this handout provided by the National Aeronautics and Space Administration (NASA), the dwarf planet Pluto is shown at distance of about 2.5 million miles July 11, 2015. NASA's New Horizons spacecraft is nearing its July 14 flyby when it will close to a distance of about 7,800 miles (12,500 kilometers). The 1,050-pound piano sized probe, which was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, is traveling 30,800 mph as it approaches. (Photo by NASA/JHUAPL/SWRI via Getty Images)
IN SPACE - JULY 11: In this handout provided by the National Aeronautics and Space Administration (NASA), the dwarf planet Pluto (R) and Charon are shown July 11, 2015. NASA's New Horizons spacecraft is nearing its July 14 flyby when it will close to a distance of about 7,800 miles (12,500 kilometers). The 1,050-pound piano sized probe, which was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, is traveling 30,800 mph as it approaches. (Photo by NASA/JHUAPL/SWRI via Getty Images)
Artist’s concept of the New Horizons spacecraft as it approaches Pluto and its largest moon, Charon, in July 2015. (Photo via NASA)
A view of Pluto and Charon as they would appear if placed slightly above Earth's surface and viewed from a great distance. (Photo via NASA)
Artist conception of New Horizons Spacecraft. (Photo by Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute via NASA) 
In this artist's rendering, Pluto's largest moon Charon rises over the frozen south pole surface of Pluto, casting a faint silvery luminescence across the distant planetary landscape. (Photo by JHUAPL/SwRI via NASA)

This map of Pluto, made from images taken by the LORRI instrument aboard New Horizons, shows a wide array of bright and dark markings of varying sizes and shapes. The elongated dark area informally known as “the whale,” along the equator on the left side of the map, is one of the darkest regions visible to New Horizons. It measures some 1,860 miles (3,000 kilometers) in length. Continuing to the right, along the equator, we see the four mysterious dark spots that have so intrigued the world, each of which is hundreds of miles across. Meanwhile, the whale’s “tail,” at the left end of the dark feature, cradles a bright donut-shaped feature about 200 miles (350 kilometers) across. (Photo via NASA-JHUAPL-SWRI)

IN SPACE - JULY 8: In this handout provided by the National Aeronautics and Space Administration (NASA), the dwarf planet Pluto (R) and it's largest moon Charon is shown at distance of about 3.7 million miles from NASA's New Horizons spacecraft July 8, 2015. The craft is nearing its July 14 flyby when it will close to a distance of about 7,800 miles (12,500 kilometers) from Pluto. The 1,050-pound piano sized probe, which was launched January 19, 2006 aboard an Atlas V rocket from Cape Canaveral, Florida, is traveling 30,800 mph as it approaches. The color information in the image, obtained earlier in the mission from instruments, has been added. (Photo by NASA/JHUAPL/SWRI via Getty Images)

This image of Pluto and its largest moon, Charon, was taken by the Ralph color imager aboard NASA's New Horizons spacecraft on April 9 and downlinked to Earth the following day. It is the first color image ever made of the Pluto system by a spacecraft on approach. The image is a preliminary reconstruction, which will be refined later by the New Horizons science team. Clearly visible are both Pluto and the Texas-sized Charon. The image was made from a distance of about 71 million miles (115 million kilometers)-roughly the distance from the Sun to Venus. At this distance, neither Pluto nor Charon is well resolved by the color imager, but their distinctly different appearances can be seen. As New Horizons approaches its flyby of Pluto on July 14, it will deliver color images that eventually show surface features as small as a few miles across.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

A Lockheed Martin Atlas V rocket carrying the New Horizons spacecraft lifts off from Launch Complex 41 at Cape Canaveral in Florida, Thursday, January 19, 2006. The New Horizons spacecraft is bound for the planet Pluto to map surface composition and temperatures, and examine Pluto's atmosphere. It will take 9 years for the spacecraft to reach the planet Pluto. (Photo by Red Huber/Orlando Sentinel/MCT via Getty Images)
KENNEDY SPACE CENTER, UNITED STATES: As photographers follow with their camera lenses, the New Horizons spacecraft atop an Atlas V rocket, disappears into the clouds 19 January 2006 at the Kennedy Space Center, Florida. Following two days of delays, the spacecraft is on a trailblazing probe to Pluto, at the solar system's outermost limits. AFP PHOTO/ Bruce Weaver (Photo credit should read BRUCE WEAVER/AFP/Getty Images)
CAMBRIDGE, MA - DECEMBER 10: Richard Binzel, a professor of planetary sciences at MIT who is part of a team working on a NASA mission to Pluto. This is a globe of the solar system. (Photo by Suzanne Kreiter/The Boston Globe via Getty Images)
UNSPECIFIED - JANUARY 17: American astronomer Clyde Tombaugh discovered Pluto, the ninth planet in our solar system, on 18 February 1930. Many key questions about Pluto, its moon Charon, and the outer fringes of our solar system await close-up observations. A proposed NASA mission called New Horizons, depicted in this artist's concept, would use miniature cameras, radio science experiments, ultraviolet and infrared spectrometers and space plasma experiments to study Pluto and Charon, map their surface compositions and temperatures, and examine Pluto's atmosphere in detail. (Photo by SSPL/Getty Images)
KENNEDY SPACE CENTER, UNITED STATES: Engineers from Johns Hopkins University check out NASA's New Horizons spacecraft 04 November 2005 in the Payload Hazardous Servicing Facility at Kennedy Space Center, Florida in preparation for its mid-January 2006 launch aboard an Atlas V rocket. The New Horizons will be the first mission to the planet Pluto and the Kuiper Belt, the journey taking about nine years. Pluto was discovered in 1930 at a distance of some 6.4 billion kilometers (three billion miles) from the sun in the heart of the Kuiper Belt -- a zone beyond Neptune 4.5-7.5 billion kilometers (2.8-4.6 billion miles) from the sun, which is estimated to include more than 35,000 objects of more than 100 kilomters (65 miles) in diameter: the remnants of the sun's accretion ring of matter from which all the planets were formed. AFP PHOTO/Bruce WEAVER (Photo credit should read BRUCE WEAVER/AFP/Getty Images)
KENNEDY SPACE CENTER, UNITED STATES: Engineers from Johns Hopkins University check out NASA's New Horizons spacecraft 04 November 2005 in the Payload Hazardous Servicing Facility at Kennedy Space Center, Florida in preparation for its mid-January 2006 launch aboard an Atlas V rocket. The New Horizons will be the first mission to the planet Pluto and the Kuiper Belt, the journey taking about nine years. Pluto was discovered in 1930 at a distance of some 6.4 billion kilometers (three billion miles) from the sun in the heart of the Kuiper Belt -- a zone beyond Neptune 4.5-7.5 billion kilometers (2.8-4.6 billion miles) from the sun, which is estimated to include more than 35,000 objects of more than 100 kilomters (65 miles) in diameter: the remnants of the sun's accretion ring of matter from which all the planets were formed. AFP PHOTO/Bruce WEAVER (Photo credit should read BRUCE WEAVER/AFP/Getty Images)
A Lockheed Martin Atlas V rocket carrying the New Horizons spacecraft lifts off from Launch Complex 41 at Cape Canaveral in Florida, Thursday, January 19, 2006. The New Horizons spacecraft is bound for the planet Pluto to map surface composition and temperatures, and examine Pluto's atmosphere. It will take 9 years for the spacecraft to reach the planet Pluto. (Photo by Red Huber/Orlando Sentinel/MCT via Getty Images)
The New Horizons spacecraft atop an Atlas V rocket lifts off 19 January 2006 at the Kennedy Space Center, Florida. The spacecraft is on a trailblazing probe to Pluto, at the solar system's outermost limits, following two days of delays AFP PHOTO/Bruce Weaver (Photo credit should read BRUCE WEAVER/AFP/Getty Images)
HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

Another possibility is a thawing and freezing ocean just under Pluto's surface, the researchers said during a NASA news conference.

The team has plenty of work ahead as data and images continue to stream in over the following days, weeks, and months.

Pluto will "send a lot of geophysicists back to the drawing boards," said Alan Stern, the team's principal investigator from the Southwest Research Institute. "We haven't found geysers and we haven't found cryovolcanoes, but this is very strong evidence that will send us looking ... for evidence of these exact phenomena."

Pluto 16x9

This is just the tip of the iceberg for Pluto. There are more questions than answers at this point. But a couple of things are clear: These preliminary images of Pluto have far exceeded the expectations of the team — and there's still a lot more to learn about this icy yet surprisingly youthful world.

NOW WATCH: Bill Nye and NASA scientists react to seeing a clear picture of Pluto for the first time

See Also:

SEE ALSO: The Pluto flyby is just the start of NASA's epic New Horizons mission

Read Full Story