It’s that time of the week again: NASA has released new images and data on Pluto and its moon Charon from the New Horizons spacecraft, and the latest batch doesn’t disappoint.
This week, a stunning new image of Pluto backlit by the Sun has been revealed. While we had seen a similar one of the sunlit crescent before, this latest image reveals the entire dwarf planet in all its glory. The wide-angle image was taken 15 minutes after New Horizons flew past Pluto on July 14, 2015.
The most amazing thing about this image is not the glorious vista on the right hand side, though. No, it is what is on the left, on the night side of Pluto. If you look at the horizon there, you can see the silhouetted profiles of features on the surface, possibly mountains or raised plateaus.
This side was in permanent darkness when New Horizons flew past. With no other mission to Pluto in the works, this is likely one of the clearest “views” you’ll ever see of the features on this side of the dwarf planet, at least for the foreseeable future. Neat.
Some of the features on the night side of Pluto. NASA/JHUAPL/SwRI.
Over on the sunlit side, you can see the informally named Sputnik Planum, the icy smooth expanse seen just below middle-centre. Above it, which is “west” in this orientation, are mountains that tower 3,500 meters (11,000 feet) above the surface. What appear to be glaciers, meanwhile, are located below (east of) Sputnik Planum.
The image also reveals the glorious layered haze of Pluto’s atmosphere, which is 90% nitrogen and 10% other complex molecules such as methane. More than a dozen different high-altitude layers in the thin atmosphere are seen here.
A close-up of the mountainous sunlit region seen in the main image. NASA/JHUAPL/SwRI.
In separate research, scientists think they may have found evidence for a crater on Charon that is younger than all the others. Informally named Organa, it seems to be rich in frozen ammonia – whereas other nearby craters, such as the Skywalker crater, are more similar to the rest of the surface and are dominated by water ice.
“This is a fantastic discovery,” said Bill McKinnon, deputy lead for the New Horizons Geology, Geophysics and Imaging team in the statement. “Concentrated ammonia is a powerful antifreeze on icy worlds, and if the ammonia really is from Charon’s interior, it could help explain the formation of Charon’s surface by cryovolcanism, via the eruption of cold, ammonia-water magmas.”
Both Organa and the nearby Skywalker crater are a similar size – about 5 kilometers (3 miles) in diameter – and also have a similar appearance. The different in composition, however, suggests Organa was created much more recently.
The craters are relatively close but different in composition. NASA/JHUAPL/SwRI.
"Why are these two similar-looking and similar-sized craters, so near to each other, so compositionally distinct?" asked Will Grundy, New Horizons Composition team lead from Lowell Observatory in Flagstaff, Arizona, in the statement.
"We have various ideas when it comes to the ammonia in Organa. The crater could be younger, or perhaps the impact that created it hit a pocket of ammonia-rich subsurface ice. Alternatively, maybe Organa’s impactor delivered its own ammonia."
Fascinating data from New Horizons will continue to be returned every week for the next year. For the spacecraft itself, it has now been maneuvered towards a new target in the Kuiper Belt, which promises to return even more fascinating science in 2019.
We’re being spoiled, really.