One of the first features on Pluto to capture the attention of researchers is a region near the icy dwarf planet’s equator that shows young mountains rivaling the Colorado Rockies at 11,000 ft. Because the region does not indicate impact craters, scientists say it could be less than 100 million years old, may still be active and made primarily from water ice. Although methane and nitrogen ice cover much of the surface of Pluto, these materials are not strong enough to build the mountains. Instead, a stiffer material, most likely water-ice, created the peaks. “At Pluto’s temperatures, water-ice behaves more like rock,” says deputy geology and geophysics team lead Bill McKinnon of Washington University, St. Louis.
Varieties of Ice
Pluto's surface has a veneer of volatile ices including nitrogen and methane. In the north, nitrogen appears to prevail. Near the equator, nitrogen levels seem lower. The infrared spectral image here shows how the measurements differ. “This is providing a lot of information about the different regions of Pluto and how they work,” says Will Grundy of the Lowell Observatory in Arizona.
Pluto’s largest moon is proving to be a topographical marvel, home to craters, cliffs and canyons that are up to 6 mi. deep. “There is so much interesting science in this one image alone,” says Cathy Olkin of the Southwest Research Institute, the deputy project scientist.
The mission’s Long-Range Reconnaissance Imager (Lorri) captured this shot of Pluto’s moon Hydra from about 400,000 mi. away. Scientists are discussing the moon’s variations in reflectivity, pointing out that the brightness of Hydra suggests that it is reflecting light — thereby indicating that its surface is likely covered with water-ice.
While speeding past Pluto on July 14, the New Horizons spacecraft is already sending back data that sheds light on the features and composition of Pluto and its moons.