Geological map of Pluto’s surface allows scientists to trace its history
NASA’s New Horizons mission scientists have created a geological map of Pluto’s surface that provides key insights into its varied terrains – as well as how they formed and evolved over time.
The base map was created by starting with a mosaic of some 12 encounter-side images taken by the Long Range Reconnaissance Imager (LORRI) an hour and 40 minutes before the July 14, 2015, closest approach, from a distance of 48,000 miles (77,300 km), each with a resolution of approximately 1,280 feet (390 meters) per pixel.
The map does not cover the entire encounter side of Pluto but highlights a region measuring 1,290 miles (2,070 km) from top to bottom showcasing the left side of Pluto’s “heart” – an extensive plain covered with nitrogen ice known as Sputnik Planum.
This particular region was chosen because it includes a wide array of surface textures and morphologies, ranging from small mounds to smooth areas, pitted regions, craggy features, and ridged landscapes.
All the images laid onto the base map have resolutions of about 1,050 feet (320 meters) per pixel, high enough for mission scientists to confidently view and map surface regions.
Each color highlights a particular type of terrain. Blue and green areas across Sputnik Planum depict its range of terrains, from the polygonal, cellular areas in the plain’s center and north to the pitted plains and smooth regions in the south. A close up of the mapped region, complete with color coding identifying its amazingly diverse terrains, is shown below.
The blocky mountain ranges that line the western border of Sputnik Planum are shown in purple while the floating ices at the opposite, eastern boundary of the plain are portrayed in pink.
Cthulhu Regio, a dark region of rugged highlands at the bottom of the image that borders the western edge of Sputnik Planum, is shown in dark brown. Large impact craters scattered along Cthulhu Regio are portrayed in yellow.
Wright Mons, a suspected ice volcano located in the map’s southern corner (bottom left of the image), is marked in red.
Troughs marking the boundaries of Sputnik Planum’s polygonal regions of nitrogen ice are represented by black lines.
By observing the patterns of the boundaries between the different terrains, scientists can see which terrains overlie others and construct a chronology for each of the different units, along with a timeline for the processes that have formed Pluto’s surface.
As an example, they can tell that the craters (highlighted in yellow) in Cthulhu Regio formed later than the terrain surrounding them.
The latest in a series of blog entries by New Horizons mission scientists, by Kimberly Ennico, project scientist and a member of the mission’s Composition Theme Team, discusses the hemispheres of Pluto and Charon opposite the encounter sides. Titled “The Many Faces of Pluto and Charon”, her entry can be viewed here.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.