NASA has released a newimage taken by the New Horizons spacecraft as it sped past the dwarfplanet Pluto, displaying the locations of a number of "floating hills" composed of water ice. It is believed that these mobile peaks brokeaway from the highlands bordering a region known as Sputnik Planum,and subsequently carried with the flow of the nitrogen ice glaciers.
The New Horizonsspacecraft has already succeeded in discovering a wealth of unusualquirks in the geology of the dwarf planet, and it seems tobe far from done. NASA scientists believe that the vast chunks ofwater, some of which measure several miles across, float on thedenser nitrogen ice flows that carry the fragments to an unusuallandscape characterized by cell-like formations.
This region of Pluto'ssurface is believed to continually refresh itself, with the materialat the centre of the cells falling beneath the surface, leaving onlythe edges of the cells behind, to be filled in by warmer blobs ofnitrogen ice that rise from the reservoir below.
As a side-effect ofthis mechanism, the water ice fragments are dragged to the edges ofthe cells, sometimes clustering in groups 12 miles (20 km) across. Therecently-released image of Sputnik Planum displays an unusually largecluster of the icebergs some 22 miles (35 km) across and 37 miles(60 km) in length.
The unusual grouping is currently believed to beevidence of chunks beaching in an area where the nitrogen ice isparticularly shallow.
Source: NASA