Pluto’s north pole

© J Marshall/Alamy

Pluto’s north pole

Pluto may no longer be considered a full-fledged planet, but it’s still the largest of our solar system’s dwarf planets and holds plenty of mysteries waiting to be discovered. Because it’s so far away—about 40 times as far from the sun as Earth is—scientists knew relatively little about Pluto until the New Horizons spacecraft reached it in 2015. In a flyby study, the craft spent more than five months gathering detailed information about Pluto and its moons, while taking photographs like those that make up this composite image.