An Ocean Under Pluto’s Heart
September 23rd, 2016, 2:17PMCould it really be possible that Pluto, orbiting so far from the warmth of the sun, might have a liquid ocean? Scientists at Brown University have come up with a fantastic scenario that helps explain some characteristics of the dwarf planet observed by NASA’s New Horizons. The team, using computer models from New Horizons data, suggest that a massive impact created Sputnik Planum, a 900-km basin that makes up the western lobe of the “heart” seen in the first photos returned from the spacecraft. The impact would have been so hard that when the surface rebounded, it pulled up material from Pluto’s interior—not just any material, but liquid water, which is denser than the ice that had been on the surface and largely blasted away from the impact. If enough water was pulled up, it would create a “positive mass anomaly” at Sputnik Planum—precisely what the data suggests, because Pluto is tidally locked with its moon Charon along an axis that goes through the basin. If this is all correct—that a liquid ocean sits underneath Pluto’s heart—it would be about 100-km deep.