New Delhi :
New images from Pluto show a giant mark on the planet’s surface. This giant ‘bite mark’ scientists suggest may have been caused by a process known as sublimation - the transition of a substance from a solid to a gas.
What does it mean?
It means that methane ice-rich surface on Pluto may be sublimating away into the atmosphere, exposing a layer of water-ice underneath, NASA said.
The image captured by NASA shows the cratered plateau uplands informally named Vega Terra.
Cutting diagonally across the mottled plans is the long extensional fault of Inanna Fossa, which stretches eastward 370 miles (600 kilometers) from here to the western edge of the great nitrogen ice plains of Sputnik Planum.
The compositional data from the New Horizons spacecraft's Ralph/Linear Etalon Imaging Spectral Array (LEISA) instrument, shown in the right inset, indicate that the plateau uplands south of Piri Rupes are rich in methane ice (shown in false color as purple) in the image.
What scientists suggest?
According to scientists, this 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.
The surface of Piri Planitia in the compositional data shows its more enriched in water than the higher plateaus which may indicate that Piri Planitia's surface is made of water ice bedrock, just beneath a layer of retreating methane ice. The surface of Pluto is so cold that water ice is rock-like and immobile.
The suspected remnant of methane that haven’t yet sublimated have also been marked as light/dark mottled pattern of Piri Planitia in the left inset as reflected in the composition map.
Previous researches have also shown Pluto's huge mountains may have vast expanses of snow covering their peaks. The LEISA data was gathered when the spacecraft was about 47,000 kilometres from Pluto.
Surface of Piri Planitia is more enriched in water ice than the higher plateau according to compositional data , which may indicate that Piri Planitia's surface is made of water ice bedrock, just beneath a layer of retreating methane ice.