Pluto: 90 years since dwarf planet's discovery

On 18 February 1930, self-taught astronomer Clyde Tombaugh discovered the dwarf planet Pluto.

Only five years earlier he built his own telescope from scratch and spent hours and hours photographing the sky.

In 1928 he started work at the Lowell Observatory in Arizona, USA, where he was instructed to identify a so-called 'Planet X'.

He eventually discovered Pluto, which was celebrated as the ninth planet in our solar system.

However, in 2006 Pluto was reclassified as a dwarf planet when astronomers realised that it was more similar to Kuiper Belt Objects than it was to our eight planets.

Pluto pictured on a Nasa telescope - once a planet, then not a planet

Despite this, we wanted to take the time to celebrate little Pluto with a quiz.

Let us know how you do in the comments!