The Summer Solstice arrived at 10:46 p.m. PDT on June 20 and summer began. Our Sun reached its most northern position, 23 1/2 degrees north of our equator, and now starts its trek toward the south.
I am enjoying the warmer nights but now we have to stay up later to see the stars. It probably appears that the constellations have picked up speed in their westward movement since winter and spring. The stars always rise 4 minutes earlier each night but in the summer it takes longer for it to get dark and so it appears that the stars are moving farther each night and therefore faster. It’s subtle, I know.
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Libra, the Balance or Scales, has but two moderately bright stars, Zubeneschamali and Zubenelgenubi. I was expecting these two to be translated as left pan and right pan or something similar. Zubeneschamali (zoo-BEN-ess-sha-MAH-lee) is Arabic meaning “the northern claw” and Zubenelgenubi (zoo-BEN-el-je-NEW-bee), “the southern claw.” By investigating these names I discovered that the Romans, during the reign of Julius Caesar, had cut off the large claws of Scorpius, the Scorpion, to form this new constellation. That made Libra the most recent addition to the constellations of the zodiac and its only inanimate member. You would think they would have renamed Zubeneschamali and Zubenelgenubi but the names still appear on today’s star maps. Zubenelgenubi and Zubeneschamali mark the two ends of the beam part of the scales or balance from which the pans of the balance hang. In Caesar’s time our Sun would have been in this group of stars at the Autumnal Equinox (about Sept. 22). Some think the Romans invented Libra because at the Autumnal Equinox there would have been a “balance” between the length of the days and nights. Others suggest they were thinking of the “balance” of the seasons between summer and winter. Very slowly since the Roman era the Autumnal Equinox has moved, due to precession, into the next constellation to the west, Virgo. Perhaps this explains why there are other stories that say Libra is the Scale of Justice that belongs to Virgo. One Greek account says Virgo was Astraea, the Goddess of Justice. According to the legend, she lived on Earth among the mortals in some perfect time in the ancient past when there was no corruption, violence or war. When these offenses began to appear she decided to leave the Earth and dwell in the sky. Her scales of justice are near her feet – actually the constellation, Libra.
The Libra part of the sky is currently receiving a great deal of attention because an Earth-like planet has been discovered there. Of the 300+ planets found outside of our Solar System so far, it is the first one to have an environment that has the temperature that allows liquid water to exist. It has been named Gliese 581 b and it is slightly larger than Earth with a temperature range of 32 to 104 degrees Fahrenheit. It is just 20.5 light years from Earth - that’s close enough to exchange a couple of messages, at the speed of light, in a lifetime. Gliese 581 b’s star cannot be seen by the naked eye but it is about the width of two fingers at arm’s length above or north of the star, Zubeneschamali, which is 160 light years from us. More exo-solar planets are being discovered in the ‘habitable zone’ in various directions from Earth but Gliese 581 b is still ranked first in the list of ‘most likely’ - http://www.planetarybiology.com.
As it gets dark on June 26 we will see a lovely crescent Moon to the lower right of Saturn and the following night our Moon will be to Saturn’s lower left, a beautiful way to drift into the night. For those who rise before our Sun, that brilliant morning “star” in the east is Venus. The dim point of light just above Venus is Mars. The bright object about the southern horizon is giant Jupiter.
Next week we will locate and explore the beauty, history, and science of Lyra, the Lyre, or Heavenly Harp.
Clear skies.
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