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Pluto Up Close: Majectic mountains, nitrogen glaciers, hazy atmosphere

Ever since last summer’s Pluto flyby of NASA’s New Horizons spacecraft, two UVA scientists have been astounded by images streaming in from the edge of the solar system: breathtaking shots of Pluto and its moons, close-up views of icy mountains, glaciers of frozen nitrogen and the dwarf planet’s hazy, tenuous atmosphere.

UVA planetary astronomer Anne Verbiscer, and UVA planetary geologist Alan Howard were among the first scientists to witness and begin analyzing photos and data.

“We’re all in awe of what we’ve seen, as well as what can be accomplished when humanity pursues its fundamental desire to explore,” Verbiscer said. “What we now know that we didn’t know is that Pluto is an incredibly rich and diverse world that will keep us busy for years to come.”

UVA’s Anne Verbiscer and Alan Howard at mission control at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Howard, called the experience “very emotional.”

“Pluto, we have found, is decorated with an amazing variety of landforms and frost features,” he said.

Verbiscer and Howard have selected a handful of images to share with Illimitable readers. In the coming years they will examine hundreds more, gaining new understanding of how planets form and evolve, and, by implication, how geological processes on Earth made conditions favorable for life.

(All images are courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.)

(Image in video, above) New Horizons captured this high-resolution, enhanced-color view of Pluto on July 14, combining blue, red and infrared images taken by the Ralph/Multispectral Visual Imaging Camera. Pluto’s surface sports a remarkable range of subtle colors, enhanced in this view to a rainbow of pale blues, yellows, oranges and deep reds. Many landforms have their own distinct colors, telling a complex geological and climatological story that scientists have only just begun to decode.

Anne Verbiscer: “Here we see Pluto in all its glory, as New Horizons instantly transformed what had been only a point of light [a blurry smudge in Hubble Space Telescope images] since Pluto’s discovery in 1930 into a world we have explored.”

Alan Howard: “The color of planetary surfaces, in both our normal visible light range and in the infrared, can inform us about the materials on the surface. These colors have resulted in identification of water ice, nitrogen ices and methane ices on Pluto’s surface, among others.”

The image above, taken just 15 minutes after its closest approach to Pluto on July 14 as New Horizons looked back toward the sun, shows the deep haze layers of Pluto’s atmosphere and rugged mountains up to 11,000 feet high.

Anne Verbiscer: “This single image is definitely one for the ages. It is without a doubt one of the most spectacular views of a planetary landscape ever returned from a robotic spacecraft. I think you’re looking at the cover of future planetary science textbooks here. The sheer variety of geologic processes is simply breathtaking: from mountain ranges rising over the horizon, to glaciers flowing, to even possible ice volcanoes. It’s got it all — a picture of unrivaled and unexpected beauty in the solar system, from an outpost farther from the sun than we have ever explored before.”

Alan Howard: “Pluto looks so welcoming in this image — mountains and plains, and a bright, clear atmosphere with just a hint of hazes. It is hard to believe that such a landscape could be so cold that the nitrogen, which is the most abundant part of [Earth’s] atmosphere, lies frozen on the surface of this distant body, forming the vast smooth plain.”

This view from New Horizons combines blue, red and infrared images. The bright expanse is the western lobe of the “heart,” informally called Sputnik Planum, which has been found to be rich in nitrogen, carbon monoxide and methane ices.

Anne Verbiscer: “This is one of those ‘wow’ images that illustrates once again the amazing diversity of terrains on Pluto, which display a broad range of compositions, colors, reflectivities and ages across the surface as a result of a variety of geologic processes.”

Alan Howard: “About 10 years ago, when the New Horizons mission was launched, it was necessary to choose what side of Pluto to visit. All that the planners had were tiny, blurry images taken by the Hubble Space Telescope. They chose to visit the brightest spot on Pluto, which turned out to be this vast expanse of frozen nitrogen surrounded by enigmatic mountains, craters and troughs incredibly more beautiful and interesting than anyone had expected.”

We’re all in awe of what we’ve seen, as well as what can be accomplished when humanity pursues its fundamental desire to explore.

-Anne Verbiscer

The Moons of Pluto

Anne Verbiscer: “Pluto’s small moons tell the story of how the Pluto system came to be. We think that Pluto and Charon formed from a collision between two Pluto-sized objects, and these small moons may be remnants from that catastrophic event.”


  • Discovered June 15, 2005
  • 5 mi. diameter
  • Orbital period of 38.2 days
  • Rotational period of 10 hours


  • Discovered June 28, 2011
  • 6-7 mi. diameter
  • Orbital period of 32.2 days
  • Double-lobed shape


  • Discovered June 15, 2005
  • 25 mi. diameter
  • Orbital period of 24.9 days
  • 6,300 times fainter than Pluto


  • Discovered June 26, 2012
  • 6-7 mi. diameter
  • Orbital period of 20.2 days
  • Highly reflective, icy surface


  • Discovered June 22, 1978
  • 753 mi. diameter
  • Gravitationally locked with Pluto
  • Surface composed of water-ice
Hover over a moon for more information.Charon Styx Nix Kerberos Hydra

New Horizons captured this high-resolution, enhanced-color view of the moon Charon just before its closest approach on July 14. The image combines blue, red and infrared images, processed to best highlight the variation of surface properties; most striking is the reddish north (top) polar region, informally named Mordor Macula.

Anne Verbiscer: “While Pluto’s mountains, valleys and plains give us vistas reminiscent of those on Earth, the region on Charon, informally named Vulcan Planum, resembles those on our own moon.”

Alan Howard: “Charon, the cratered satellite of Pluto, is in some ways similar to other moons we have visited in the solar system. But it wears an enigmatic red hat and a unique broad crumpled sash of broken rock.”

Just 15 minutes after its closest approach to Pluto on July 14, New Horizons looked back toward the sun and captured a near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named Sputnik Planum (at right) is flanked to the west (left) by rugged mountains up to 11,000 feet high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. The backlighting highlights more than a dozen layers of haze in Pluto’s atmosphere. The image was taken from a distance of 11,000 miles to Pluto; the scene is 230 miles across.

Alan Howard: “The mountaineers among the readers will have caught on to the significance of the informal names for these major peaks: Hillary and Norgay were the first to scale Mt. Everest.”

Base to Summit Height (in feet)

  • 16,000
  • 12,000
  • 8,000
  • 4,000
  • 0
  • Mount Everest
  • Norgay Montes
  • Hillary Montes
  • Mount Mitchell, NC

Calculated heights are from base to summit.

What’s on the Horizon for the UVA Scientists?

An expert on the planets of the solar system, Anne Verbiscer is playing a key role in determining New Horizon’s flight path beyond Pluto to icy objects in the Kuiper belt, a vast debris- and comet-strewn region rimming the solar system. “I am working with Hubble Space Telescope data to help refine targeting, so New Horizons can explore entirely new classes of outer-solar-system objects,” she said.

Alan Howard has made a 50-year career of comparing geological surface processes on Earth and Mars, as well as on moons of Jupiter and Saturn. He is best known for studying the processes that shaped Earth, and using that to inform knowledge about the terrain of Mars — and vice versa. He now is looking at areas on Pluto where asteroids may have impacted, regions of erosion, ice deposits, and how the atmosphere has interacted with the surface.