Names for the Planets
Celestial Objects

The Sun

 Our solar system is often called heliocentric because the sun is at the center.  The purpose of that sentence was not to teach you science, but to point out the three different word roots that are used to refer to the star that gives life to our planet, sun, helios, and sol.
  In ancient Greek myths Hyperion was the god of the sun, but eventually this became more associated with his son, helios.  An eclipse in India in 1868 offered an opportunity to do something never before done, pass light from the Sun's atmosphere through a spectroscope.  When light passes through a spectroscope it breaks into bands of unique colors that represent pure elements.  One color was at a position never found on Earth.  Assuming that the element only occured in the Sun, Astronomer Norman Lockyer named it Helium, "sun element".  Later it was found on earth, but the name stuck.

    When the Romans conquered the Greeks, their fascination with the Greek culture led to retaining many of the same myths, with the major characters replaced with a related Roman god.  The Roman god associated with the sun was Sol, and thus we get words like solar system, parasol , and solarium (sun room). The para in parasol is not the same as the para in parabola and parallel, but comes from the Latin parare, which means to prepare. A parasol is thus preparation for the sun.

  The word sun, itself, may come from the same Indo-European root that gave us sol, or perhaps there is an old Norse or Tutonic god out there I haven't found yet. However it started, it made its way from the Germanic into the Middle English as sunne to become our sun of today.

Another Greek word for our closest star was elector, which meant something loosely like "bringer of light". Things that reminded them of the brillance or color of the sun, such as amber, were called electrum. Even the early Greeks were aware of the effects of magnets and recoginzed that, when rubbed, amber acted like a magnet to some small light objects. In 1600 when English Scientist William Gilbert wrote De Magnete Magneticisque Corporibus, the similarity of the behavior of magnets to the effects of amber inspired him to create the word electricity from the Greek word for amber. The unit of magnetomotive force in the CGS system is called the Gilbert in his honor. Gilbert is buried in St. Johns College Chapel in Cambridge, Uk.

By now you've probably figured out that the name for the electron also is related. When JJ Thompson discovered the particle we now call the electron while studying the mysterious cathode rays in tubes, he called them corpuscles. The Word, Electron had been coined earlier by G. Johnstone Stoney in 1891. Stoney used the word to denote the unit of charge found in experiments that passed electric current through chemicals. He had written about the unit of charge as early as 1874, making him one of (if not the) first to recognize that, in his words, "For each Chemical bond which is ruptured within an electrolyte a certain quantity of electricity traverses the electrolyte, which is the same in all cases." He first referred to the unit quantity as E1.

In the same sense the term was used by Joseph Larmor, J.J. Thomson's Cambridge classmate. Larmor devised a theory of the electron that described it as a structure in the ether . But Larmor's theory did not describe the electron as a part of the atom. When the Irish physicist George Francis FitzGerald suggested in 1897 that Thomson's corpuscles were really "free electrons," he was actually disagreeing with Thomson's hypotheses. FitzGerald had in mind the kind of "electron" described by Larmor's theory. The idea did not stick, but the name did. [see photo of the tablet on the outside of Cavendish Laboratory in Cambridge, UK]


In ancient times, great generals and rulers sent their messages from place to place by messengers.  Ancient gods also needed a messenger, it seems, and they chose Hermes, the son of Maia (this Maia is the Greek daughter of Atlas, not to be confused with the Roman Maia from whom we get the name for the month of May, confusing isn't it.).  To carry messages for the gods one would have to be swift, and Hermes had wings on his helmet and his sandals.  He was not just fast of foot, his quick mind made him also the Greek god of invention and commerce.  When the Greeks saw a planet rushing through the sky faster than any of the others, they named it for the winged messenger.

Later the Greeks adopted Thoth, the Egyptian god of Learning and sort of melded him with Hermes, who was then renamed Hermes Trismigestus (triple great), and vested him additionally as the god of alchemy (chemistry).  The Egyptians were the early leaders in chemistry, and the word alchemy comes from the Arabic name for Egypt, al khem, for the black land.  It is a short step from chemistry to medicine, since the same learned men did both, and so Hermes Trismigestus also was associated with medicine.  When a messenger went from place to place they would carry a staff to let people know they were protected by some potentate and should not be messed with.  This symbol was called a caduceus (ka-doo' syoos) from an old Doric Greek word for a herald.  Hermes staff may have started out with olive branches wrapped around it, but as snakes became more and more associated with doctors (snakes can shed their skin, sort of like rebirth from the dead) the staff was decorated with coiled snakes.  This symbol is still associated with the practice of medicine today, and is the insignia of the army medical corps.

When the Romans came, they associated their god of commerce, Mercury, with Hermes.  You can find more about the myth of Mercury/Hermes at a site provided by Hermograph Press. Hermes name is also preserved in a scientific term for airtight, hermetic. Supposedly one of the things that Thoth/Hermes/Mercury did was create a way to make vessels airtight.

  The Germans also had a god associated with Mercury. His name was Woden, from which we get the name for Wednesday which was once "Woden's day". Here is a link from Enchanted Learning that gives lots of scientific data about Mercury.


The planet second most distant from our sun, appears sometimes in the morning sky and at other times in the evening sky. For this reason it is often called both the morning star and the evening star. For a long time the ancients did not realize it was the same planet, and so they named the one that appeared in the eastern sky just before the light of dawn, Phosphorus , Greek for "light bringer." The element phosphorus has that name because white phosphorus gives off a bright light in air. The name for the same planet when it was west of the sun at dusk was called Hesperus from the Greek word for west. Greek legends told of an island at the west end of the world where a group of nymphs and one dragon protected the garden in which the golden apples were grown.

When the Greeks figured out they were both the same planet, they renamed the planet Aphrodite, after the Greek goddess of beauty and love, perhaps because it is the brightest star in the heavens. The Roman goddess with the same description was Venus. Venus (Aphrodite) supposedly wore a cestus, a girdle or belt, which made her beauty irresistible. This name is preserved today in the zoological name for a type of salt-water flat worm that grows to about four feet in length and resembles a belt.

Venus is the only planet named for a goddess, a sign of the high value the Romans placed on her. Venus was so loved by the Romans that a verb, venerate, came into existance to mean "honor or respect". But then as we were taught to respect the elderly, the old wise men of the community were said to be vererable. From the epitome of beauty to an old man is a short step. I guess that is what they mean when they say "Beauty is in the eye of the beholder." Here is a link from Enchanted Learning that gives lots of scientific data about Venus.

The sixth day of the week in the Roman Calendar was also named for Venus, and was called, "Dies Veneris", the day of Venus. The old Norse did not have a goddess of love, but they did have a loving goddess, Frigga, the wife of Odin. She was considered to be the Mother of all and the patron of marriages. When they renamed the Roman days of the week in their local tounge they named this day after Frigga. Today we have shortened "Frigga's day" into Friday


The Greek God of War was Ares, the son of Zeus and Hera. When he went to war he took along his two sons, Phobos (fear) and Deimos (terror). The name of Phobos remains today in the psychological term phobia for an unreasonable or abnormal fear. Perhaps because the fourth planet from the sun seemed to have a reddish cast that reminded them of blood, the Greeks named the planet for Ares. The Romans replaced the Greek name with that of their own god of war, Mars. Mars is also the source of the name of the third month, March. In many cultures the name for the day we call Tuesday is Marde or Marte, also in honor of Mars. Our Tuesday comes from Tyr or Tiw which was the Norse God of War. When the Germanic Tribes (the Angles and the Saxons) invaded England in the sixth century they conquered a culture that had been controlled by Rome for two hundred years and used the Roman names for days of the week. They simply replaced Mars with their own god of war and called the day tiwesdaeg.

You can see a picture of how Mars/Aries might have looked at this site from The Learning Company, Inc. Here is a link from Enchanted Learning that gives lots of scientific data about Mars.

In 1877 Asaph Hall, an American astronomer, discovered two small moons around mars. He gave them the names of Ares children, Phobos and Deimos. And if you wonder how Ares feels about losing out to Mars, you may feel better knowing that his name is preserved in the name of a red giant star, Antares, which means opposite mars. It was probably named because they both appear about the same size and have a reddish glow, but in actual fact, Antares is one of the largest of all the stars known, far bigger than our sun. Ares also had other children who appear in the solar system names. Ares and Aphrodite(Venus) had a child who was as loving as Ares was warlike. His name was eros, but he is better known today by his Roman name, cupid. In 1898 a small planetoid (Asteroid) was found that actually lay between the orbit of Earth and Mars. G. Witt, the German who discovered it, chose to name the tiny fifteen mile diameter planetoid for Eros. Later when more planetoids were found with orbits closer to the Earth than Mars or Venus they too received masculine names. One of them, which actually comes closer to the Earth than the moon, is called hermes.