The Planetarium Science Center, an affiliate to the Bibliotheca Alexandrina, is organizing a lecture on Neptune, the blue giant. The lecture is a thorough exploration of Neptune and the outer Solar System. It also presents in detail the story of the discoveries of Uranus, Neptune, and Pluto. In addition, the lecturer explains the new definition of the term planet, devised by the International Astronomical Union, and why Pluto was officially demoted to the rank of dwarf planets.