Mercury occupies the twilight zone. In the pale territory between light and shadow, the planet now skirts the hem between sunset and night. Before year's end it will complete two more excursions east of the Sun, but this is its most favorable evening performance of the year.
Viewed from Earth, Mercury appears to migrate beyond each flank of the Sun and back again in a cycle that takes 116 days. No planet moves as quickly through the sky. The ancients were aware of Mercury's oscillation between evening and dawn and recognized in it the same bipolar behavior they witnessed in Venus. However, they had to work harder to spot it in Mercury, which never strayed far from the Sun.
Personal appearances of Mercury always confine it to twilight or dawn, in the border between Earth and sky, because its orbit is inside ours. It is the planet nearest the Sun, and leading or led, it's always on a short leash. Mercury thus hugs the horizon and remains half hidden in the light the Sun leaks into the sky. It's easy to miss Mercury, and most people have never seen it. Even Copernicus complained it eluded him.
Crossing the western threshold soon after dark this month, Mercury takes its cue from the Roman god of commerce and travel for whom it is named and dons the Cap of Hades. This hat confers invisibility on the planet and allows it to slide into the underworld beyond the rim of our gatefold star chart. Mercury drops out of sight too early to make the map, but you may find it with the help of the horizon vignette in the Sun, Moon, and Planets section of the gatefold, where Mercury is still on border patrol.
Astronomers in ancient Mesopotamia were aware of Mercury's yo-yo travels. The Sumerians, who built the world's first cities in the Tigris-Euphrates river valley, must have noticed it 4,000 years ago, for the Assyrians were still using a Sumerian name for the planet - Gud - in astrological omens they inscribed in the seventh century B.C. Usually its presence favored good rains, the land's fertility, and commodity surpluses. Assyrian names for Mercury referred to its relatively pale light and to its "jumping" movements.
The Assyrians assigned Mercury to the god Nabu. His name means "herald," and he was also the divine sponsor of knowledge. Usually portrayed with a writing stylus, Nabu served as recording secretary in the congress of the gods. At their New Year assembly he wrote down destinies for the coming year on the Tablets of Fate. This implies his duties included reading and recording celestial messages.
Acquiring planet lore from Mesopotamia, the Greeks called Mercury the "star of Hermes" and affiliated it with a divine middleman. The god Hermes promoted travel, commerce, and communications and so embodied some of the same attributes the Assyrians saw in Nabu. His talent as a foxy manipulator and magical facilitator is documented in Greek myth. The Homeric Hymn to Hermes, composed about the same time the Assyrians were documenting the intentions of heaven, salutes Hermes as wily and cunning. He was a robber and cattle rustler, a night prowler, and an agent of dreams. Astoundingly precocious, Hermes stole Apollo's cows on the first night after his birth.
Hermes easily slipped past the checkpoints that separated the realms of the gods and spirits from the world of mortals. He escorted souls to the underworld. Heroes called to him for guidance at death. The planet plays a similar role, for when we see Mercury it is either emerging from the underworld as a "morning star" or returning there as an "evening star."
The Romans later laminated the character of Hermes onto Mercury, a deity whose Latin name remains in circulation. in words like mercantile and mercurial. They reflect Mercury's traditional charter - business activity and rapid movement.
Lively and erratic, Mercury delivered messages for the gods. If Rome had had cable television, Mercury would have skyrocketed to stardom in infomercials. The earliest references to his quicksilver messenger service are in Homer's Odyssey, where the courier of Zeus is dispatched with a notice for Calypso, the nymph with the beautiful braids, that it's finally time to let entranced Odysseus leave for home.
Mobility and speed are Mercury's hallmarks. They mean quick delivery and swift communication. For those talents Mercury was adopted as the trademark of Florists' Transworld Delivery, guaranteed to get your bouquet to its destination while the flowers are still fresh. The Astronomical Society of the Pacific courts Mercury in its emblem and co-opts his mastery of time and space by naming one of its publications in his honor. An automobile was named after the fleet-footed god in the golden sandals, and it nosed through traffic with a figure of Mercury as its hood ornament. Mercury also promises safe and speedy travel from his cornice perch on Manhattan's Grand Central Terminal.
The planet Mercury has the same keys to the highway as its divine namesake. Mobility is what lets the planet take two more ventures to the end of its trade route in the western twilight this year. When it reaches the limit like that, it is said to possess its greatest eastern elongation. With a total of three more business trips on its itinerary to the dusk, Mercury stakes a claim to the reputation of another version of the god of magical transactions, Hermes Trismegistus, or "Thrice-great Hermes."
Hermes Trismegistus was a product of internationalized Mediterranean culture. Hellenistic philosophers saw him primarily as the author of astrological texts, but he gradually accumulated the responsibility for other occult sciences as well as theological insight. By the third century A.D. Neoplatonists were giving him credit for writing the most valuable digests of magical wisdom and the most important treatises on esoteric knowledge.
Manetho, the Graeco-Egyptian historian who lived in the middle of the third century B.C., reported the Hermetic Books totaled 36,525 volumes, a number symbolically linked with the length of the solar year and with a legendary chronology of Egyptian history. Notwithstanding this impossible success in publishing, Hermes Trismegistus traced some of his divinity to Egypt. He evolved from a late version of Thoth, the ibis-headed god the Egyptians believed invented hieroglyphic writing and kept the calendar. Thoth also weighed the souls of the dead and so shouldered some of the same obligations fulfilled by Nabu and Hermes. Vulnerable to the reconciling tendencies of the Hellenistic era, Thoth was equated with Hermes.
Astronumerological symbolism like the tally of books in the Hermetic library reflects Graeco-Roman notions about the antiquity of Egypt. Archaic Egypt, they judged, was the source of mystical knowledge. Even though Thoth's calendrical duties bonded him with the Moon, Greek and Roman influence established his alliance with the planet Mercury. In time the Thoth/Hermes hybrid turned into Hermes Trismegistus, the master of astrology, alchemy, and other magical arts.
With what seemed to the ancients like magical speed, the planet Mercury races through heaven. Its identification with the messenger of Zeus is usually explained by its motion. In Mercury: The Elusive Planet planetary scientist Robert Strom repeats what others have said before: "Because this planet traveled more rapidly than others, the Greeks named it Hermes, messenger of the gods and herald of Zeus." Historian Tamsyn Barton echoes this analysis in Ancient Astrology: "It was perhaps the speed of the planet's movements which led it to be identified with the messenger."
Mercury's moves no doubt inspired our ancestors' admiration of its snappy shuttle service, but there is more to Mercury than meets the eye. In fact, its occupation of the low frontier is what allows it to function as an emissary of gods. Even when it travels to the end of its trail and is most conspicuous, it is still anchored to the twilight or the dawn. The planet's territory echoes the god's parentage, for Hermes was the son of Zeus, the ruler of the bright celestial vault, and Maia, the eldest sister in the starry Pleiades.
Mercury was born for the border. It's the child of the night and the daytime sky. It can never fly too far from Earth, and its attraction to the horizon cultivates its image as a cosmic go-between. Its real calling is perimeter patrol and infiltration. No matter where the planet is, it is never far from the underworld and never far from heaven.
Mercury's strength is transformation and exchange. Like a shaman, he talks with spirits, negotiates with gods, and traffics in magic. The planet, like the god, operates at the edge, beyond the pale.
E. C. KRUPP merchandises the cosmos and monitors the fringe at Griffith Observatory in Los Angeles.
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|Title Annotation:||planet Mercury and Roman deity 'Mercury'|
|Publication:||Sky & Telescope|
|Date:||Mar 1, 1998|
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