The Latin word is Terra. In science fiction stories a human being from Earth may be an "Earthl;ng" or an "Earthman," but he is frequently a "Terrestrial," while a creature from another world is almost invariably an "extra Terrestrial."
The Romans also referred to the Earth as Tellus Mater ("Mother Earth" is what it means). The genitive form of tellus is telluris, so Earthmen are occasionally referred to in s.f. stories as "TeHurians." There is also a chemical element "tellurium," named in honor of this version of the name of our planet.
But putting Earth to one side, the first two heavenly bodies to have been noticed were, undoubtedly and obvi ously, the Sun and the Moon, which, like Earth, are old Teutonic words.
To the Greeks the Sun was Helios, and to the Romans it was Sol. For ourselves, Helios is almost gone, although we have "helium" as the name of an element originally found in the Sun, "heliotrope" ("sun-turn") for the sun flower, and so on.
Sol persists better. The common adjective derived from sun" may be "sunny," but the scholarly one is "solar."
We may speak of a sunny day and a sunny disposition, but never of the "Sunny System." It is always the "Solar System." In science fiction, the Sun is often spoken of as Sol, and the Earth may even be referred to as "Sol Ill."
The Greek word for the Moon is Selene, and the Latin word is Luna. The first lingers on in the name of the chemical element "selenium," which was named for the Moon. And the study of the Moon's surface features may be called "selenography." The Latin name appears -m the common adjective, however, so that one speaks of a "lunar crescent" or a "lunar eclipse." Also, because of the theory that exposure to the li ht of the full Moon drove men crazy ("moon-struck"), we obtained the word "lunatic."
I have a theory that the notion of naming the heavenly bodies after mythological characters did not originate with the Greeks, but that it was a deliberate piece of copy cattishness. . To be sure, one speaks of Helios as the god of the Sun and Gaea as the goddess of the Earth, but it seems obvi ous to me that the words came first, to express the physical objects, and that these were personified into gods and goddesses later on.
The later Greeks did, in fact, feel this lack of mytho logical character and tried to make Apollo the god of the Sun and Artemis (Diana to the Romans) the goddess of the Moon. This may have taken hold of the Greek scholars but not of the ordinary folk, for whom Sun and Moon remained Helios and Selene. (Nevertheless, the in fluence of this Greek attempt on later scholars was such that no other impo rtant heavenly body was named for Apollo and Artemis.)
I would like to clinch this theory of mine, now, by taking up another heavenly body.
After the Sun and Moon, the next bodies to be recog nized as important individual entities must surely have been the five bright "stars" whose positions with respect to the real stars were not fixed and which therefore, along with the Sun and the Moon, were called planets (see Chapter 4).
The brightest of these "stars" is the one we call Venus, and it must have been the first one noticed-but not necessarily as an individual. Venus sometimes appears in the evening after sunset, and sometimes in the morning before sunrise, depending on which part of its orbit it happens to occupy. It is therefore the "Evening Star" some times and the "Morning Star" at other times. To the early Greeks, these seemed two separate objects and each was given a name.
The Evening Star, which always appeared in the west near the setting Sun, was named Hesperos ("evening" or 44 west"). The equivalent Latin name was Vesper. The Morning Star was named Phosphoros ("light-bringee'), for when the Morning Star appeared the Sun and its light were not far behind. (The chemical element "phosphorus" - Latin spelling-was so named because it glowed in the dark as the result of slow combination with oxygen.) The Latin name for the Morning Star was Lucifer. which also means "light-bringer."
Now notice that the Greeks made no use of mythology here. Their words for the Evening Star and Morning Star were logical, descriptive words. But then (during the sixth century B.c.) the Greek scholar, Pythagoras of Samos, arrived back in the Greek world after his travels in Babylonia. He brought with him a skullfull of Babylonian notions.
At the time, Babylonian astronomy was well developed and far in advance of the Greek bare beginnings. The Babylonian interest in astronomy was chiefly astrological in nature and so it seemed natural for them to equate the powerful planets with the powerful gods. (Since both had power over human beings, why not?) The Babylonians knew that the Evening Star and the Morning Star were a single planet-after all, they never appeared on the same day; if one was present, the other was absent, and it was clear from their movements that the Morning Star passed the Sun and became the Evening Star and vice versa. Since the planet representing both was so bright and beautiful, the Babylonians very logically felt it ap propriate to equate it with Ishtar, their goddess of beauty and love.
Pythagoras brought back to Greece this Babylonian knowledge of the oneness of the Evening and Morning Star, and Hesperos and Phosphoros vanished from the heavens.
Instead, the Babylonian system was copied and the planet was named for the Greek goddess of beauty and love, Aphrodite. To the Romans this was their corresponding goddess Yenus, and so it is to us.
Thus, the habit of naming heavenly bodies for gods and goddesses was, it seems to me, deliberately copied from the Babylonians (and their predecessors) by the Greeks.
The name "Venus," by the way, represents a problem.
Adjectives from these classical words have to be taken from the genitive case and the genitive form of "Venus" is Veneris. (Hence, "venerable" for anything worth the respect paid by the Romans to the goddess; and because the Romans respected old age, "venerable" came to be applied to old men rather than young women.)
So we cannot speak of "Venusian atmosphere" or "Venutian atmosphere" as science fiction writers some times do. We must say "Venerian atmosphere." Un fortunately, this has uncomfortable associations and it is not used. We might turn back to the Greek name but the genitive form there is Aphrodisiakos, and if we speak of the "Aphrodisiac atmosphere" I think we will give a false impression.
But something must be done. We are actually exploring the atmosphere of Venus with space probes and some adjective is needed. Fortunately, there is a way out. The Venus cult was very prominent in early days in a small island south of Greece. It was called Kythera (Cythera in Latin spelling) so that Aphrodite was referred to, poetically, as the "Cytherean go'ddess." Our poetic astron omers have therefore taken to speaking of the "Cytherean atmosphere."
The other four planets present no problem. The second brightest planet is truly the king planet. Venus may be brighter but it is confined to the near neighborhood of the Sun and is never seen at midnight. The second brightest, however, can shine through all the hours of night and so it should fittingly be named for the chief god. The Babi lonians accordingly named it "Marduk." The Greeks followed suit and called it "Zeus," and the Romans named it Jupiter. The genitive form of Jupiter is fovis, so that we speak of the "Jovian satellites." A person bom under the astrological influence of Jupiter is "jovial."
Then there -is a reddish planet and red is obviously the color of blood; that is, of war and conflict. The Baby lonians named this planet "Nergal" after their god of war, and the Greeks again followed suit by naming it "Ares" after theirs. Astronomers who study the surface features of the planet are therefore studying "areography." The Latins used their god of war, Mars, for the planet. The genitive form is Martis, so we can speak of the "Martian canals."
The planet nearest the Sun, appears, like Venus, as both an evening star and morning star. Being smaller and less reflective than Venus, as well as closer to the Sun, it is much harder to see. By the time the Greeks got around to naming it, the mythological notion had taken hold. The evening star manifestation was named "Hermes," and the morning star one "Apollo."