Pluto
When it was discovered in 1930, Pluto was classified as the ninth furthest planet from the Sun, however it has since been demoted to dwarf planet status. This is due to observations of similar sized bodies in the Kuiper Belt that Pluto calls home, hence it did not meet one of the three criteria that the International Astronomical Union has to define a planet, it ‘has not cleaned its neighbouring region of other objects’. Pluto has five moons of its own but is only about one sixth of the mass of our Moon. When NASA’s New Horizons visited Pluto in 2015 it discovered frozen methane dunes on the dwarf planet's surface.
Messages from the edge of the Solar System: What New Horizons is still revealing about Pluto and beyond
As the New Horizon’s spacecraft ventures deeper into the distant Kuiper belt, we take a look at what we’re learning from this groundbreaking mission.
Surprises are in store for the New Horizons’ fly by
There will be no New Year’s Eve revelry for those working on NASA’s New Horizon’s space probe.
What is the biggest a moon can be in relation to its mother planet?
The Earth’s moon is 27 per cent of its size, but how far this size ratio can be pushed depends on your very definition of a ‘moon’.
Public decides on demonic naming system for Pluto
New discoveries on the surface of the dwarf planet Pluto will be named after denizens of the underworld after public vote.
See every New Horizons picture of Pluto in one image
Nearly a year after the New Horizons passed Pluto, the spacecraft is still sending back incredible photos of the dwarf planet.
Is there a ninth planet on the outskirts of our solar system?
Sorry Pluto, but we’re not quite ready to reinstate you to full planet status – there could be another more mysterious Planet 9 well beyond you.
The final frontier: what will we find on Pluto?
As NASA's New Horizons spacecraft nears Pluto, Govert Schilling explores what we might find waiting for us on this alien world.
New Horizons captures Pluto in colour
Three months before it's due to sweep past the distant dwarf planet, NASA's New Horizons has sent back its first colour image of Pluto.
What drew Pluto into the Solar System?
Planet or not, Pluto has been a part our our solar system as long as the rest of them, but how did it come to join us?
Could Neptune and Pluto ever collide, as their orbits intersect?
New Horizons captured the public's imagination with stunning new images of Pluto. Could we lose this dwarf-planet to its neighbour, Neptune?