This frozen region of Pluto has been informally named Sputnik Planum (Image: NASA/JHUAPL/SWRI)
The latest pictures from New Horizons have revealed yet another baffling terrain on the surface of Pluto: fresh icy plains that are less than 100 million years old, and could be even more recent.
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鈥淲hen I saw this image for the first time I decided I was going to call it 鈥榥ot easy to explain鈥� terrain,鈥� said team geologist Jeff Moore in a press conference earlier today at NASA headquarters in Washington DC. 鈥淭his could be only a week old, for all we know.鈥�
This region, informally named Sputnik Planum after the Earth鈥檚 first artificial satellite, is right next door to the icy mountain terrain shown earlier this week .
That location has now been dubbed Norgay Montes, after the Nepalese Sherpa who made the first ascent to the summit of Mount Everest.
The plains are broken up into irregular shapes about 20聽kilometres wide, with shallow troughs in between.
Some of these troughs are filled in with dark material, and others even contain small hills. It鈥檚 possible these shapes are created by convection within Pluto, heating and melting the surface likely a slowly bubbling pot of porridge. Or, they could be formed by contractions of the surface, similar to the processes that produce mud cracks on Earth.
鈥淲ho would have expected this kind of complexity?鈥� said mission lead Alan Stern. 鈥淲e can see that there are stark contrasts on Pluto in terms of the geology.鈥�
There are even tantalising hints of plumes erupting from the surface, as we know happens on Neptune鈥檚 icy moon Triton. The team have not seen the plumes directly, but they see dark smudges that appear to be aligned behind objects sticking out of the plains. They could also be created by winds blowing at speeds of a few metres per second and lifting up small particles.
Data on Pluto鈥檚 atmosphere is also making its way back to Earth. Measurements from ground-based telescopes had previously seen only the dwarf planet鈥檚 largely nitrogen atmosphere at altitudes of between about 50 and 300 kilometres.
Now New Horizons has seen it all the way from the surface of Pluto to about 1600 kilometres out, further than the radius of the dwarf planet itself. Ionised nitrogen escaping from the atmosphere also seems to be forming a tail behind the Pluto system, blowing in the solar wind of charged particles from the sun.
The team also presented our first pixelated look at Nix, one of Pluto鈥檚 smaller moons, and confirmed the presence of a large region of carbon monoxide at Tombaugh Regio, the heart on Pluto鈥檚 surface. This region had previously been noted from Earth, but New Horizons has now confirmed that there is nothing else like it on the surface, and the team doesn鈥檛 have an explanation for it.
New Horizons has now uploaded just 1聽or 2聽per cent of the data gathered during its fly-by earlier this week, but more is on the way. Researchers are as fascinated as they are confused by what they鈥檙e seeing, and the findings at Pluto show it is every bit as complex as the other planets we鈥檝e explored. 鈥淚 think the solar system saved the best for last,鈥� said Stern.
