It’s been all of five minutes since the last big news story about Pluto so high time for another. NASA recently released the image below which, whilst not on a par with previous ones when it comes to sheer breathtaking beauty, is, nonetheless, scientifically intriguing.
What we have here is an aerial view of a geological feature that looks rather like a shield volcano here on earth. It is about 100 miles across and 13,000 feet high but the really curious thing about it is the depression in the centre which is reminiscent of a crater.
This is unusual because Pluto is so small and so far from the sun that scientists had previously thought that there was no way that it could have any heat left in it, and without heat there is no energy for planetary activity. On earth we get heat from the sun which drives our weather systems and heat from the hot, molten, radioactive core of the planet which give us earthquakes and vulcanism; both phenomena being able to sculpt and renew the surface. Pluto has neither and, yet, there is clear evidence that parts of the surface are relatively new and so there must be some mechanism that allows the movement of material that we are as yet unaware of.
The next image shows the photo above, plus another with a similar volcano-like feature; both have been coloured to show different heights in the terrain to make the crater-like feature more apparent.
The key difference between our volcanoes and those of Pluto is the temperature. Ours spew out red hot molten rock at more than 1,000oC, on Pluto the temperature would be nearer -240oC. Instead of magma the eruption would be more of an icy slurry, probably a mixture of liquid nitrogen and maybe some ammonia too.
To be clear, scientists are not yet saying that these definitely are volcanoes, there could certainly be other explanations, but one scientist involved in the project has described volcanoes as being the ‘least weird’ possible interpretation. This is the latest in a string of surprises that Pluto has thrown up and, once again, it has got heads scratching. With more than 6 months still to go until the last of the New Horizons data returns to earth I think it’s a safe bet that it won’t be the last.