The hunt for alien life has been given a boost after scientists discovered a habitable planet almost the same size as Earth.
Astronomer Thomas Barclay from Nasa's Ames Research Centre in California made the discovery using data collected by the Kepler space telescope.
The unnamed planet was found orbiting an unidentified star in its so-called Goldilocks zone - a region around the star that emits just enough energy, light and temperature for liquid surface water to appear.
Neptune was supposedly discovered in 1846 by Johann Gottfried Galle using calculations by Urbain Le Verrier and John Couch Adams, making it a joint British-French-German discovery.
But these astronomers were not the first to observe Neptune. That honor goes to the famous Italian astronomer Galileo Galilei.
While sketching the moons of Jupiter with his newly discovered telescope, Galileo twice drew Neptune, which happened to be in conjunction with Jupiter in early 1613. It's usually said that Galileo mistook Neptune for a star because of its slow movement.