We are in a great era of space exploration. This magnificent photo of Pluto (colour-enhanced, but otherwise a true visual image) was taken by the New Horizons probe, which is now more than six billion kms from Earth. New Horizons, launched in 2006, is entering the vast outer regions of our solar system, which we are discovering is far bigger and more complex than was ever imagined. The heart-shaped plain called Sputnik Planitia is an ocean of nitrogen ice, which is semi-fluid and shows dynamic features similar to those that occur in polar pack-ice on Earth. Adjacent to it is a mountainous region charmingly named Cthulhu Macula, which seems to be coloured by hydrocarbon tars.