re space news from feb aw st in article apr dazixco ingr com jbreed ingr com writes pluto s atmosphere will start to freeze out around and after about increasing areas of both pluto and charon will be in permanent shadow that will make imaging and geochemical mapping impossible where does the shadow come from there s nothing close enough to block sunlight from hitting them i wouldn t expect there to be anything block our view of them either what am i missing you re assuming that their normal rotation carries all areas of the surface into sunlight not so even on earth each pole gets several weeks without sunlight in mid winter pluto and charon have much more extreme axial tilt and a much longer orbit pluto s north pole for example gets over a century of darkness followed by over a century of perpetual light at the moment we re in luck pluto and charon are just past their equinox when the sun was just on the horizon at both poles of each if we get probes there soon only the immediate vicinity of one pole on each will be in long term shadow this will get steadily worse the longer we wait all work is one man s work henry spencer u of toronto zoology kipling henry zoo toronto edu utzoo henry
