It’s Monday. It’s NASA. It’s Pluto. Why fight it?
Why, indeed, when there seems to be a never ending stream of stunning images being beamed back by the New Horizons probe? Looky here:
As usual, check out the full size image here.
This image is interesting for a number of reasons. Firstly, it gives more detail on Pluto’s hazy atmosphere which, whilst very thin, is somewhat more substantial than anyone had predicted. Secondly, although the haze appears to be blue its components are actually reddish coloured tholins, so that’s a bit of a mystery. The tholins are what gives Pluto its now distinctive reddish patches on the surface, but they are actually created up in the atmosphere.
Nitrogen and methane molecules in the atmosphere are ionised (split apart) to form more highly reactive species that are able to combine with each other. The reactive ions can grow and grow with the addition of more and more volatile gases until they start to form these red tholin particles that then fall down to the surface.
Another new picture released at the same time ties into this. Below you can see a wonderful close up of the surface with certain areas highlighted in blue (original here). These patches represent areas where the surface is covered in water ice, most of the surface being covered in nitrogen ice, methane ice and others. Curiously, these water ice regions match up quite closely with the reddish tholin rich areas. Why this would be the case is yet another surprising question the dwarf planet is posing us.