These were the only planets that were bright enough for them to see. Later, when telescopes were used, other planets were discovered. Astronomers decided to continue naming the planets after Roman Gods. Neptune, a blueish planet, was named after the Roman god of the sea. read more
Urbain Le Verrier, who discovered the planet, claimed the right to name his discovery: Neptune. Soon Neptune became the internationally accepted name. In roman mythology, Neptune was the god of the sea. read more