Members of the New Horizons mission team have discovered a huge ‘bite mark’ on the surface of the dwarf planet Pluto.
‘Bite mark’ on Pluto. The image at left was obtained by NASA’s New Horizons spacecraft at a range of 21,100 miles (33,900 km) from Pluto. The LEISA data at right was gathered when New Horizons was 29,000 miles (47,000 km) from the dwarf planet. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute.
The southern portion of the left image above shows the cratered plateau uplands Vega Terra.
A wall of cliffs, known as Piri Rupes, borders the young plains of Piri Planitia. The cliffs break up into isolated mesas in several places.
Cutting diagonally across the mottled plans is the long extensional fault of Inanna Fossa, which stretches eastward 370 miles (600 km) from here to the western edge of the great nitrogen ice plains of Sputnik Planum.
Data from New Horizons’ LEISA infrared spectral imager, shown in the right image above, indicate that the plateau uplands south of Piri Rupes are rich in methane ice (purple).
“Sublimation of methane may be causing the plateau material to erode along the face of the cliffs, causing them to retreat south and leave the plains of Piri Planitia in their wake,” New Horizons scientists said.
The LEISA data also show that Piri Planitia’s surface is more enriched in water ice (blue) than the higher plateaus, which may indicate that the surface is made of water ice bedrock, just beneath a layer of retreating methane ice. Because the surface of Pluto is cold, the water ice is rock-like and immobile.
The light/dark mottled pattern of Piri Planitia in the left image is reflected in the composition map, with the lighter areas corresponding to areas richer in methane – these may be remnants of methane that have not yet sublimated away entirely.
‘Bite mark’ on Pluto. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute.
According to NASA, New Horizons is currently 3.28 billion miles (5.28 billion km) from Earth and 180.3 million miles (290.2 million km) beyond Pluto, with all systems healthy and operating normally.
The spacecraft is on course for a close flyby of the Kuiper Belt object 2014 MU69 in 2019.
