Each week, we look forward to new and exciting Pluto announcements, and this week is definitely no exception. Just five months ago we were on the edge of our seats, anticipating the first-ever up-close views of the icy world.
Now, with less than half of the data collected by New Horizons beamed back to Earth, we are just beginning to understand it.
Included with the latest images is a mosaic like we saw last week. However, in this series of images we see a variety of rugged terrain as opposed to the smooth icy shores of Sputnik Planum. Also featured is Wright Mons, a possible cryovolcanic edifice according to NASA.
Along with these incredible new images are detailed scientific findings revealing the secrets of Pluto’s geography, atmosphere and moons. The research was presented today during the American Geophysical Union’s Fall Meeting.
We’ve seen Pluto resemble the Earth in remarkable ways. This week, scientists presented evidence for “hanging valleys” like the ones in Wyoming’s Yellowstone National Park. The presence of these eroded valleys are geological evidence indicating there was widespread glacial activity both in Pluto’s past and its present.
Alan Howard, a scientific collaborator with the New Horizons’ Geology, Geophysics and Imaging team, said in a statement: “Pluto has greatly exceeded our expectations in diversity of landforms and processes – processes that continue to the present.”
As New Horizons’ principal investigator Alan Stern has said previously that what we knew about Pluto when New Horizons "could fit on one sheet of paper," and soon we will be able to "write the textbook.” However, before we can write the book, we need to understand the processes taking place on this icy world. Scientists believe the key to understanding Pluto’s geological activity is to understand the role of nitrogen and other volatile ices.
Pluto has a heart – as seen in the iconic post-flyby image – with two very different lobes. The left side is a vast, icy basin covering an area 1,000 kilometers (620 miles) wide. Unofficially dubbed Sputnik Planum, after the first satellite launched into space, the region is littered with icy polygonal features and covered in nitrogen ice. New numerical models show that thermal convection is taking place within the icy layers of the planum and are the driving source behind the unusual polygons. The models show this area is still being transformed today by glacial flows of nitrogen ice, erasing any evidence of craters or scarring.
Unlike the smooth icy plains of Sputnik Planum, the right side of Pluto’s frozen heart is covered in strange pits and rougher terrain. Unofficially named Tombaugh Regio after the man who discovered Pluto, Clyde Tombaugh, the region appears to be older than the neighboring planum. This region of Pluto is scarred by vast chasms and chock full of impact craters and even mountains that tower above the surface – basically tons of interesting surface features to stare at. The new images show details resolve features as small as 500 meters (1,640 feet) across, revealing Pluto’s contrasting surface in stunning detail.
Adjacent to Tombaugh Regio in Pluto’s western hemisphere is Wright Mons, one of two potential cryovolcanoes on Pluto. Similar to the shield volcanoes we see on Earth, Wright Mons and Piccard Mons have a broad, circular basin with a deep depression at the summit. However, instead of lava and ash, cryovolcanoes would spew a melted slurry of water ice, ammonia and other volatiles.
Also included in the latest image release is a new view of Nix, Pluto’s third largest moon. This is one of the best images we have of Pluto’s potato-shaped moon and shows a heavily cratered surface. The image was taken on the day of the flyby, July 14, and at a distance of 23,000 kilometers (14,000 miles).
Image in text: The full new mosaic of Pluto. NASA/JHUAPL/SwRI