Uranus is the seventh planet in the solar system, the third largest, and the fourth most massive. It is named in honor of the Greek god of heaven Uranus (from the ancient Greek "Οὐρανός"), the father of Crono (Saturn) and the grandfather of Zeus (Jupiter). Although it is detectable to the naked eye in the night sky, it was not cataloged as a planet by astronomers of antiquity due to its low luminosity and the slowness of its orbit.13 Sir William Herschel announced his discovery on March 13, 1781, expanding the then known borders of the solar system, for the first time in modern history. Uranus is also the first planet discovered by means of a telescope.
Neptune is the eighth planet in distance from the Sun and the farthest from the solar system. It is part of the so-called outer planets or gaseous giants, and it is the first one that was discovered thanks to mathematical predictions. Its name was put in honor to the Roman God of the sea - Neptune -, and it is the fourth planet in diameter and the third largest in mass. Its mass is seventeen times that of Earth and slightly larger than that of its "twin" planet Uranus, which has fifteen land masses and is not as dense. On average, Neptune orbits the Sun at a distance of 30.1 ua. It astronomical symbol is ♆, a stylized version of the trident of the god Neptune.
Uranus and Neptune