Scientists using the Hubble telescope believe they have discovered hydrocarbon molecules on Pluto, which could go some way to explaining the origins of life as well as the planet’s unusual colours.

Pluto is slightly less red than Mars but its swirling surface colour varies between charcoal black, white and dark-orange. One of the most mysterious planets the tiny planet orbits in darkness, “the last rock from the sun.”

Astronomers used Hubble to detect “absorbers” of ultraviolet light. The absorption could be due to the sunlight mixing with gasses locked in the ice on the planet’s surface, a reaction which may cause Pluto’s “ruddy” colour.

The "absorbers" also point to the presence of hydrocarbons.

Made up entirely of hydrogen and carbon, hydrocarbons are found in crude oil on Earth.

The discovery is exciting because humans are essentially carbon-based life forms. Hydrocarbons have also been found in the atmospheres of Jupiter and Saturn. It's posited that hydrocarbons were vital during the formation of life on Earth

"The discovery we made with Hubble reminds us that even more exciting discoveries about Pluto’s composition and surface evolution are likely to be in store when Nasa’s New Horizons spacecraft arrives at Pluto in 2015," said Alan Stern of the Southwest Research Institute.