From midnorthern latitudes in June, Scorpius and Libra are at their most visible around midnight. Find a low southern horizon if you want to see Scorpius in its entirety.
Last week we spoke of the ecliptic, that mysterious line in the sky along which the sun, moon and planets seem to move. It has been called by other names such as "the Road of the Sun." The constellations along the ecliptic are called the "zodiac."
Of the twelve zodiacal constellations, Libra is the only star pattern that does not represent a person or an animal.
Is it Lee-bra or Lī-bra?
Many years ago, one of the long-time lecturers at New York's Hayden Planetarium reprimanded me after I had given a sky show and pointed out Libra to my audience:
"Listen," he said, "the correct pronunciation is "Lī-bra," not "Lee-bra." Remember, you go to a lī-brary, not a lee-brary!"
I initially did not believe him, especially since I knew that the word library had its origins from the Latin word "libraria" (meaning book), while Libra was Latin for "balance," hence two totally different things. But when I returned home and did some checking, I found that the World Book Encyclopedia (Field Enterprises Educational Corporation) indeed suggested the pronunciation LY-bruh, while The American Heritage Dictionary of the English Language (Houghton Mifflin Company) deems both Lī and Lē as acceptable.
Now, whenever I look at Libra, I always think of my former Hayden colleague and in deference to him, stress the Lī.
Out of balance
Known as "The Scales" or "The Balance," Libra is marked by an oblong figure of stars and owes its importance only to its position in the zodiac. It supposedly consists of a beam with two pans hanging from it, for weighing things.
The load in the right-hand pan must be heavier, for the balance is tilted down on that side. Libra was once associated with the constellation Virgo, as the scales of the goddess of Justice which that figure was supposed to represent.
Just to the east (left) of Libra on these early June evenings, the most beautiful zodiacal constellation can be found emerging into view low in the southeast sky: Scorpius, the Scorpion. Scorpions have two large claws in front, but this one seems to have had his claws clipped. In fact, the claws were indeed cut off to form Libra. A few thousand years ago, Romans decided that there should be 12 constellations in the zodiac, instead of 11, so they made the two claws of Scorpius into the arms of Libra, the Balance.
Libra was also known as "the Claws" of Scorpius, the Scorpion, to the poet Aratus and others of classical times. In fact, two of Libra's stars still bear the Arabic names, Zubeneschamali and Zubenelgenubi, meaning respectively, "Northern Claw" and "Southern Claw." Zubeneschamali also has a very faint greenish tinge: the only green naked-eye star.
A fishhook and cat's eyes
The whole figure of the Scorpion is a magnificent sight sort of a "celestial fishhook" and is best appreciated now in a dark sky without any interference from bright moonlight. It really looks like a huge scorpion, with its long stinging tail curled over its back. I should point out here that the currently accepted name of this constellation is Scorpius, not Scorpio.
Principally astrologers (and some older astronomy books) use the latter for labeling the zodiacal sign of that name.
One star clearly outshines the others, with a fiery tinge seemingly emphasizing the Scorpion's sinister appearance. That's Antares, the so-called "rival of Mars," "Ares" being Greek for Mars. Antares is a supergiant, 700 times the sun's diameter, over 9,000 times as luminous and located 604 light years away. And lastly, the stars Shaula and Lesath are a close pair of stars in the Scorpion's stinger. Astronomy popularizer Hans A. Rey (1898-1977) christened these stars the "Cat's Eyes," noting, "You will find the name quite fitting."
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.
- Constellations at SPACE.com
- Gallery: Zodiac Constellations
- The Scales and the Scorpion