Pluto may contain a colossal underground ocean, say New Horizons mission scientists.
Two new Letters in Nature, Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto and Reorientation and faulting of Pluto due to volatile loading within Sputnik Planitia considers the icy heart-shaped “lava lamp” found on the former planet's surface.
The new Letters suggest that the Sputnik Planitia faces in the wrong direction and ended up that way after something knocked the dwarf planet off balance.
One theory is that Pluto was struck by something big, creating the crater Sputnik Planitia inhabits. That impact also cracked Pluto, sending lots of volatile materials to the surface. Those materials froze, but formed in such quantities that Pluto tilted.
None of this would be possible, the Letters suggest, if Pluto's innards weren't liquid.
At this point Reg readers may protest that it's always mighty cold out Pluto way, so how could anything be liquid even under a couple of hundred kilometres of rock? There's two answers to that conundrum. Firstly, Pluto's still got some nuclear action going on way down below, plus some tectonic activity. Together, they keep its core warm enough that liquids are feasible. Secondly, there's a decent chance Ammonia has formed out there and it helps to keep freezing points low.
The Letters suggest the oceans are extensive, perhaps 100km deep and rivalling the volume of Earth's bodies of water.
Pluto's therefore being tentatively added to the growing list of locations with ingredients that could conceivably foster life as we know it. And of course the presence of something watery also offers all sorts of fuelling-up possibilities if humanity gets its space travel act together. ®