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'Virgin' Constellation's Bright Star Reigns Over Night Sky

virgo-sky-map-spica-may-2012

In our night sky, just one constellation is officially known as "The Queen" (the autumn star pattern Cassiopeia), but if we could assign an unofficial title of "Queen of Spring" for northern observers, then certainly it would have to go Virgo, the Virgin.

Virgo currently covers much of the southern sky during the late evening hours (9 to 11 p.m. local daylight time) this week. The constellation consists of a group of stars set in a large dim region that owes its importance mainly to its location within the zodiac.

Among the 88 constellations, in terms of size (at least according to official boundaries that were established in 1930 by the International Astronomical Union), Virgo is the second largest, spanning 1,294 square degrees, or nearly 3 percent of the entire night sky. Only Hydra, the long and winding water snake, is larger.  

Virgo is supposed to represent Astraea, the daughter of the Greek god Zeus and Titaness Themis, the personification of the goddess of Justice who was the last of the deities to abandon the Earth at the end of the fabled Golden Age. 

The only conspicuously bright star in Virgo is Spica, a bluish-white star of great luminosity. Spica is so far away that its light requires 260 years to travel across the vast gulf of space that separates it from Earth. 

Since light travels at 186,282 miles (299,792 kilometers) per second, it is obvious that Spica must be far brighter than the sun but tremendously far away. Indeed, Spica is a brilliant helium-type star, about 2,300 times brighter than our home star. [Telescopes for Beginners]

Spica ranks as the 16th brightest star in the night sky and can be regarded as an almost perfect example of a star of the first magnitude. Astronomers refer to a star's magnitude to determine how bright it appears in the night sky. Put simply, the lower the magnitude of a star or object, the brighter it appears in the sky.

As listed in the 2012 Observer’s Handbook of the Royal Astronomical Society of Canada, its magnitude is given as 0.98, though the star can actually vary slightly at irregular intervals from 0.95 to 1.05. It also has a tiny invisible companion that was discovered while analyzing its light with a spectroscope in the year 1890.

Queen of Wheat

The name Spica comes from the Latin "Spicum," and is said to signify a spike or ear of wheat. It is derived from the ancient allegorical drawings of the goddess, whose figure was somehow traced around the scattered stars by the imaginations of primitive stargazers.

In many parts of the classical world, she is the "Wheat-Bearing Maiden" or the "Daughter of the Harvest."  The goddess was shown holding several spears of wheat in each hand and Spica is in one of the ears of grain hanging from her left hand, evidently representing the harvest time which occurred when the sun was passing this bright star.

Interestingly, in another legend, Virgo supposedly represented Persephone, the daughter of the goddess of the harvest, Ceres, and as such, is typically associated with agricultural matters.

The only astronomy reference book that outlines the stars of Virgo differently, and hence "goes against the grain" as to where Spica is located is in the popular guidebook "The Stars/A New Way to See Them" by the late H.A. Rey (1898-1977). [Video: Which Telescope is Right for You?]

Rey pictured Virgo lying on her back and stretched out along the ecliptic. As for Spica, Rey referred to it as Virgo’s brightest jewel, but located "on an unusual spot." (For those who do not have a copy of Rey’s book, that "unusual spot" is her derrière).

This spring, Spica happens to have some company in the night sky. The planet Saturn, shining sedately with a yellow-white glow, currently gleams about six degrees above and to the left of Spica. (Your clenched fist held at arm’s length measures roughly 10 degrees.)

Using a telescope magnifying at least 30-power will show Saturn's famous rings, which are now inclined 13-degrees to our line of sight. Saturn glows at magnitude +0.4, noticeably brighter than Spica.

Prophetic Words from the ‘50s

Henry M. Neely, who passed away in 1963, was known as "The Dean of New York Stargazers" and lectured until he was well into his 80s at New York's Hayden Planetarium. Among the various objects that he would point out during a typical planetarium lecture, Spica was among his favorites. Back in the 1950s, Neely would often train his electric arrow-pointer on Spica and remark that: 

"Spica could have been totally destroyed at the time of the signing of our Declaration of Independence, yet men would still be seeing it shining serene and undisturbed in its accustomed place until the babies who are now in their mothers' arms are aged men, cursing their rheumatism and the younger generation in the same breath."

Considering that the light that left Spica back in 1776 still has another 24 years to reach us, it probably will cause those "baby-boomers," born during the 1950's (like myself), who gaze at Spica tonight to pause and reflect on old Neely’s prophetic words!

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.