Less than a fortnight out from New Horizons’ flyby of everyone’s favourite maligned dwarf planet, Pluto, the spacecraft is starting to reveal details of the planet’s surface features.
Pluto appears red like Mars, but for very different reasons. Mars’ colouring is due to iron oxide (rust, basically) in
its soil. But according to NASA in Pluto’s case it is, “likely caused by hydrocarbon molecules that are formed when cosmic rays and solar ultraviolet light interact with methane in Pluto’s atmosphere and on its surface”.