Explore Alliance Presents: How Do You KNOW? – Episode #52: ''Who Discovered Neptune?"

From its discovery in 1846 until Clyde Tombaugh's discovery of Pluto in 1930, Neptune was the farthest-known planet. Now with the controversial recategorization of Pluto being a "Dwarf Planet", Neptune has regained its status as the farthest-known major planet of our solar system.

But the discovery of Neptune itself is not without drama and controversy: Johann Gottfried Galle, using calculations by Urbain Le Verrier and John Couch Adams, is credited with the discovery in 1846. But In 2009, a study reviewing Galileo's drawings on 28 December 1612 and 27 January 1613 contain plotted points that match up with what is now known to have been the positions of Neptune on those dates. And although faithfully recorded, Galileo did not recognize he had found another planet.

So, who should receive recognition for the discovery? One who was the first to actually see it and record it, even though he did not know what it was, or to someone who tracked down the object, specifically looking for a planet? This the topic of Dr. Daniel Barth in the 52nd How Do You KNOW?