Why are the planets Mercury, Venus, Mars, Jupiter, and Saturn named as they are?
Why are the planets Mercury, Venus, Mars, Jupiter, and Saturn named as they are?
Wikipedia and various astronomical websites from around the world provide the following explanations:
Mercury: “The planet that moves fastest around the Sun, so the Romans named it after the fastest god, Mercury.”
Venus: “The planet was considered the brightest and most beautiful star in the sky, so it was named in honour of the goddess of love.”
Mars: “The Romans named the planet after the god of war because of its blood-red colour.”
Jupiter: “The Romans named the largest of the planets after the god Jupiter because he was the most important among the gods.”
Saturn: The reasons for this name are not always explained. Saturn is the Roman name for the Greek god Cronus, the father of Zeus (Jupiter). Sometimes it’s said that Saturn was the god of time, and that this planet moves very slowly.
It’s not surprising that such explanations are prevalent, as they were even featured on the website of planetary nomenclature in 2021, developed jointly with the International Astronomical Union [1]. However, as noted by Peter Gainsford, a reputable researcher of Greek antiquity, these explanations are inaccurate and spun out of thin air [2].
- Mercury: The explanation is inaccurate as people in ancient times couldn’t determine the true orbital speed of the planet. They could only observe its apparent speed, which doesn’t significantly differ from that of Venus. Interestingly, the Akkadian name for Mercury, "šihṭu" (leap), corresponds to its movement around the Sun. However, there’s no indication of a similar connection with the god Mercury.
- Venus: It’s the brightest planet (excluding the Sun and Moon, which ancient astronomers considered planets). But who said brightness means “beauty”? That statement isn’t supported by ancient astronomers. Moreover, Venus/Aphrodite was more associated with lust and sexual desires rather than beauty. Therefore, the explanation that “brightness = beauty” is false.
- Mars: Some planet names may relate to their colour, such as the Chinese name Huǒxīng, meaning “fire star,” or the late Egyptian name “Horus red.” However, the Romans were not obligated to do the same, and these names generally mean “red,” not “bloody.” There’s likely no Greco-Roman source linking the colour of Mars to blood.
- Jupiter: Astronomers in antiquity had no means of determining Jupiter’s size, radius, or mass.
- Saturn: As the last planet visible to the naked eye and moving slowly, Saturn in Roman mythology was probably associated with the god of agriculture, though this connection with Cronus is doubtful. Similarly, Cronus may have some link to time, but it’s unlikely that Saturn does.
The actual explanation for the origin of the names (Mercury and Venus) is that these names are Latinized translations of Greek names (“star of Hermes” and “star of Aphrodite”). The Greek names, in turn, were borrowed from the deities of Babylonian astronomy - a form of homage to tradition.
Below are the names of the planets and their associated gods in Babylonian, Greek, and Latin:
- Nabu/Ninurta - Hermes/Apollo – Mercury
- Ishtar - Aphrodite/Hera – Venus
- Nergal - Ares/Hercules – Mars
- Marduk - Zeus – Jupiter
- Ninurta - Cronus – Saturn
We don’t know why the Babylonians associated these planets with the gods Nabu, Nergal, or Marduk. Notably, these gods were not linked to attributes like “speed” or “beauty.” It’s essential to understand that the planets themselves were not considered gods; Greek astronomers referred to them as “the star of Hermes,” “the star of Aphrodite,” and so on.
In poetic contexts, the planets could metaphorically represent the gods. For more detailed information and explanations about these nuances, refer to Peter Gainsford’s article [2]. Following the publication of his article, which includes numerous references to the source materials, the false explanations disappeared from the planetary nomenclature website of the International Astronomical Union [3].
Prepared by Dmytro Filipchuk 
