How the Planets in Our Solar System Got Their Names

Organized by IAU and Zooniverse, it is the first opportunity for the public to name a list of 20 most popular ExoWorlds (exoplanets).

The International Astronomical Union (IAU) is the internationally recognized authority that is responsible for naming all celestial bodies in this universe. Established in the year 1919, the IAU works to promote and safeguard the science of astronomy in all its aspects, through international cooperation.

A planet, according to IAU, is a celestial body that
(a) is in orbit around the Sun
(b) has sufficient mass for its self-gravity to overcome rigid body forces, so that it assumes a hydrostatic equilibrium (nearly round) shape
(c) has cleared the neighborhood around its orbit

Have a look at how these rocky and gaseous bodies came to be christened after mythological characters.

Mercury, Venus, Mars, Jupiter, and Saturn were named thousands of year ago. The rest were not discovered until a few hundred years back. The IAU recognizes and thus carries forward the tradition of naming the planets after Roman and Greek deities.

The IAU Working Group for Planetary System Nomenclature (WGPSN) is the body that finalizes and assigns names to any newly discovered celestial body or the features on their surface.

As kids, we must have found these nine names difficult to remember. It is only with some trick that we succeeded in memorizing them; of course, better if they are memorized in the correct order.

All the planets, except for Earth, are named in a similar fashion. A common thread among all is their association to Greek or Roman mythology. Pluto is not considered a planet now, but since it was earlier, and has some history to its naming, it has been included here.

We cannot forget this little celestial body which is closest to the Sun. The Romans named this planet 'Mercurius', because its movement in the sky appears very quick and swift. It is also identified as the Messenger of the Gods (or of Jupiter). Known as 'Hermes' in Greek mythology, it refers to the god of commerce, theft, cunning, and invention.

If you have ever gone out for star gazing, this is one of the first identifiable objects in sky. Venus is beautiful, prominent, and the brightest amongst all. The term 'Venus' represents the Roman Goddess of Love and Beauty. Also, it is known as the counterpart of the Greek Goddess Aphrodite.

Interesting fact: Until it was evident that both are the same object, this planet was called 'Lucifer' as a morning star, and known by the name 'Venus' as an evening star.

We don't make a guess here! This is not any Roman goddess representing life, or any other emotion. In fact, as you might have even noticed, many languages use similar terminology for denoting the Blue Planet.

The term stems from the Indo-European base of 'er', which formed the German noun 'ertho'. In German language, the Earth is known as 'Erde', in Dutch 'Aarde', in Scandinavian 'Jord', and in English it is 'Earth'.

The red color of this planet is the reason behind its name. The Romans named it their God of War due to its blood-like appearance. He was also the father of Romulus and Remus. Ares is his Greek counterpart. In other civilizations too, its peculiar red color has created its names; 'Her Desher' is the name for Mars in Egypt, which means the 'the red one'.

Jupiter symbolizes the King of Gods for the ancient Roman culture. Being the largest of all the planets in our solar system, 'Jupiter' seemed to be the perfect nomenclature for this massive gas giant. This planet is called 'Zeus' by the Greeks. With the symbols of a lightening bolt and an eagle, Jupiter was the most significant deity for these civilizations.

Saturn is the Roman God of Agriculture and Vegetation. This planet, with its famous concentric rings of ice particles, has a Roman name that is interpreted to be the Greek Kronos (or Cronus). According to Roman mythology, Saturn is the father of Zeus (or Jupiter), Neptune, and Pluto.

Uranus was discovered in 1781 by William Herschel, who had earlier named the planet 'Georgian Sidus' after George III. Later that year, Johann Bode named it 'Uranus', or God of the Sky, or the Heavens for the Greeks. Also, as per Greek mythos, Kronos is the son of Uranus, and Jupiter is the grandson of Uranus.

Another planet with a magnificent blue color, besides Earth, is Neptune. It was discovered by Johann Gottfried Galle in 1846, based on the predictions made by Urbain Le Verrier. Perturbations in the orbit of Uranus gave way to its discovery.

Initially, Galle wished to name his discovery after Le Verrier, but it was not agreed upon by the international astronomical community. So, it was named after the Roman God of Sea. Poseidon is the Greek deity similar to this Roman sea god.

Since the 2006 resolution of IAU that published the definition of what constitutes a planet, Pluto was no more in the list of nine. Discovered by Clyde Tombaugh in 1930, it is understood to be a dwarf planet instead. It is named after the Roman God of the Underworld. It also exemplifies the eternal darkness that is associated with its distant location.