Timeline of discovery of Solar System planets and their moons

They will be known only by the numbers X and XI, written in Roman numerals, and usually prefixed by the letter J to identify them with Jupiter."[2]).

The International Astronomical Union (IAU) eventually started officially approving names in the late 1970s.

In the 5th century BCE, the Greek philosophers Philolaus and Hicetas speculated separately that the Earth was a sphere revolving daily around some mystical "central fire" that regulated the universe.

[3] The Earth's position in the Solar System was correctly described in the heliocentric model proposed by Aristarchus of Samos.

In his work Kosmotheôros[16] (published posthumously in 1698), Christiaan Huygens relates "Jupiter you see has his four, and Saturn his five Moons about him, all plac’d in their Orbits."

The numbering of Titania and Oberon underwent some confusion, because in 1797, Herschel reported four more satellites of Uranus[23] that turned out not to exist.