NASA releases a series of photos as the New Horizons probe approaches showing areas of intermediate brightness and also very bright and very dark surface features. The probe is 4.7 billion km (2.9 billion miles) from Earth and 39 million km (24 million miles) from Pluto.
Even though the latest images were made from more than 30 million miles away, they show an increasingly complex surface with clear evidence of discrete equatorial bright and dark regions—some that may also have variations in brightness. We can also see that every face of Pluto is different and that Pluto’s northern hemisphere displays substantial dark terrains, though both Pluto’s darkest and its brightest known terrain units are just south of, or on, its equator. Why this is so is an emerging puzzle.