Icy basin in heart of Pluto 'may be natural sinkhole'
The deep icy basin in Pluto's heart-shaped region may be a natural sinkhole, a study has claimed.
A team led by University of Maryland astronomer Douglas Hamilton suggests the basin may have resulted from the weight of surface ice.
Computer modelling by the researchers indicates an ice cap formed at that location early in Pluto's history.
A ll the ice may have caused the underlying crust to slump, creating the 600-mile-wide basin in the "left lobe" of the heart, now called Sputnik Planitia.
Other models point to a crater caused by an impact.
Nasa's New Horizons spacecraft unveiled Pluto during last year's historic fly-by.
Two weeks ago, another study in the journal Nature suggested there was an ocean beneath Sputnik Planitia. Mr Hamilton said that still could be the case.