Planets of the solar system have been named with Roman mythology gods names. I have a few questions on my mind concerning that subject for a while:

  • Who decided to name them like this?
  • When did the planets got named?

Finally, the ultimate question is: if the planets got named by the Romans, implying they had not technology to observe the solar system whatsoever, why some of the names match the color of the planets?

  • Mars is red - Mars is the god of war
  • Neptune is blue - Neptune is the god of the oceans

Or maybe I am wrong (most likely) and the planets have been named more recently.


Cavemen were able to see the first six planets, up to Saturn. All these planets were named after the Roman and Greek mythological characters.

The rule they followed was something like this: The planet will be named after the Roman god and all its satellites will be named after the corresponding Greek gods. For example, Jupiter was named after the Roman King of Gods, and one of its satellites, Ganymede , was named after the man-servant of Zeus. Now Zeus is the Greek counterpart of Jupiter.

Now, Uranus is the lone exception for this scheme. All of its satellites, Miranda, Ariel, Umbriel, Titania, and Oberon were named after Shakespearean characters. This was to please the British because, they were very powerful in that period of time and its discovery was made by William Herschel in the 1780's.

P.S. Uranus was first named 'George' by Herschel because the King of England, King George, was his main source of funding and he didn't want to annoy him.

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    $\begingroup$ First of all: there is no evidence that "cavemen" could distinguish planets from fixed stars. Second: the satellites of the planets (other than Earth) were not known until after the invention of the telescope. Third: "Cavemen" did not speak Greek or Latin. Need I continue? This answer is nonsense. $\endgroup$
    – fdb
    Apr 5 '15 at 17:56

Despite of the explanation of your question, it is a valid question to ask why planets all have Roman names. First of all, the Romans could, like the Greeks and Sumerians, could only see Mercury, Venus, Mars, Jupiter and Saturn. These planets can be seen with the naked eye. However, the fact that the Romans could see these planets, didn't give all the planets latin names.

If the Names of the planets were given by the ones that discovered them first, the planets would have Sumerian names. The answer to the question why the planets have latin names is because they don't. The first western scientist took over the Roman names, because latin was they scientific language of the middle ages and the renaissance. After the discovery of Uranus and Neptune these planets were not given these names by their discoverers. Only after longer controversy western astronomers have standardized the names of planets and moons according to Greek and Roman mytholohy, but this was only around the second half of the 19th century.

Since the beginning of the 20th century the IAU is setting the standards for naming celestial bodies including planets. However, the IAU doesn't set the names, it only sets the standards. Newly discovered objects are now named according to these rules by their discoverers. Older planets are still living with their old names and for western astronomers those are still the names from Greek and Roman mythological figures. However, the IAU allows you to consistently name the planets by their Arabic or Chinese names. So, the question is valid, the text around your question is unfortunately not true, since the planets don't necessarily have Roman names. If you are An Asian person and correctly think the planets should have their Chinese names, because they were earlier in discovering these objects than the Romans (although not earlier than the Sumerians), you are allowed by the IAU (sic) to call them by their Chinese names.

  • $\begingroup$ So my question is a bit different from the one i asked. Maybe I should repost one: I don't understand how Mercury, Venus, Mars, Jupiter and Saturn can be seen with the naked eye. $\endgroup$
    – qleguennec
    Mar 20 '15 at 22:15
  • $\begingroup$ They are close enough? $\endgroup$
    – MacUserT
    Mar 21 '15 at 6:42
  • $\begingroup$ I get that, but I haven't personally seen them with the naked eye. $\endgroup$
    – qleguennec
    Mar 21 '15 at 12:42
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    $\begingroup$ That's pretty difficult, since the planets are not that big and not recognized by just looking at them. The ancient people used view finder sticks to focus on a single object in the sky. The planets were interesting objects, because they moved more rapidly and extraordinary across the sky than the other stars. That's why Greeks called them "planetos", which means "wandering star". The planets Mercury and Venus can only be seen in the evening or morning with the Sun and can't be seen at night. $\endgroup$
    – MacUserT
    Mar 21 '15 at 13:44
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    $\begingroup$ @qleguennec Unless you live in a place where you can't really see stars at all, you have almost certainly seen them - you just didn't know what you were seeing, as to the casual observer they wouldn't look all that different than stars. Venus, in particular, is one of the brightest objects in the sky other than the Sun and Moon. $\endgroup$ Apr 3 '15 at 2:29

Mercury, Venus, Mars, Jupiter and Saturn had been named as such in ancient times after various gods. We can speculate that Mercury (named after the speedy messenger god) is fast moving, Venus (a god of love and beauty) appears white and beautiful. Mars looks red as blood (appropriate for a god of war). Jupiter is the brightest planet that can reach opposition to the sun, and so appear at midnight. Saturn is slow moving and was a "grandfather" god. The use of Latin names reflect the influence that Roman civilisation had on the development of European culture.

Herschel, the discoverer of the planet Uranus named it Georgium Sidus, "George's star" after his patron, King George III of Great Britain.

The name was not popular outside of Great Britain, and there were various other proposals. It was Johann Elert Bode who proposed Uranus, the Latin form of the Greek god of the sky. It fits with the existing planets having the names of Roman Gods, and just as Saturn was the father of Zeus, so Uranus was the father of Saturn.

Neptune was named, apparently after as a major God that did not have a planet.

All these names were well established by the time of the founding of the IAU in 1919


The question also asked about how it came to be that the colors of some of the planets matched their names. By the time Neptune was discovered, people had telescopes and could see its color. But Mars was given its current name by the ancient Romans, and the answer to how they knew it was red was that they looked up in the sky with their naked eyes and saw it. Mars is brighter than most stars and looks distinctly reddish.

Remember that, in Roman times and for a long time after, star were just points of light in the sky, and planets were just special stars that moved from night to night relative to the other stars. Mercury moved the fastest, so it was named after the messenger of the gods. Venus was brightest, so it was named after the goddess of beauty. Earth was not a planet. Mars, being reddish, was named after the god of war. Jupiter is bright but slow moving; perhaps that indicated grandeur, but honestly I'm speculating there. And Saturn was the god of time, so maybe that seemed to fit the planet that took the longest to repeat a cycle.


The names are in Sanskrit and mean something in Sanskrit.

  • Chandra is the Moon
  • Surya is the Sun
  • Mangala is Mars
  • Bhuda is Mercury
  • Jupiter is Guru (weighty in Sanskrit as its size was known from Surya Siddhanta)
  • Shukra is Venus
  • Saturn is Shanischara (slow-moving in Sanskrit)

The week days are ordered in that order of increasing distances except for Venus (I do not know why.) All planets are considered gods!

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    $\begingroup$ I believe the OP is asking about the names of the planets as used by the IAU, I.e. the Roman names. $\endgroup$
    – HDE 226868
    Apr 29 '19 at 22:42
  • $\begingroup$ India studied astronomy first and we should accept those names. India also discovered the nutation period of Earth as 27000 years for which at least 5000 years of data is required. Indians have been observing the star configurations for a very long time so that events can be dated from star maps in the literature. $\endgroup$ Apr 30 '19 at 0:57
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    $\begingroup$ With all respect, that's irrelevant; regardless of your personal opinions, these are the names used by the scientific community. $\endgroup$
    – HDE 226868
    Apr 30 '19 at 1:02
  • $\begingroup$ Uranus is for Varuna (in Sanskrit), the same god (or equivalent), so Roman is just fine. $\endgroup$ Jun 17 '19 at 13:38

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