Colored Lights In the Night
The waxing moon reaches full phase Sunday. Saturday it shines less than 10 degrees — the span of an average fist held at arm’s length — below Saturn, the only visible evening planet. The next night, the full moon is farther to the east of Saturn, and the star Regulus five degrees above it. Saturn and Regulus appear about equally bright, both near first magnitude, but Saturn’s steady golden glow is a sharp contrast to the twinkling, blue-white star.
Regulus, the lion’s heart, marks the spot at the bottom of a grouping of stars that looks like an inverted question mark. Rotating more than 100 times faster than our sun, Regulus is one of the fastest spinning objects in the heavens, and if it spun any faster, it would rip apart. Five times the size of our sun, Regulus burns much hotter, shining more than 150 times brighter than the sun.
Monday and Tuesday the moon shines to either side of Libra. With no stars brighter than second magnitude, the celestial scales are easy to overlook. Were it not along the ecliptic, it would not be among the zodiac and might not even be a constellation. In fact, eons ago, Libra was part of Scorpius, its two ends the scorpion’s claws. Then, sometime around 2000bc, early astronomers noticed that during autumnal equinox — when day is balanced equally between light and dark — the sun rose with these stars. And so it was that Libra was born. The brightest of the group is the scale’s fulcrum, Zubenelgenubi. But of greater interest is the beta star, Zubeneschimali, marking the scale’s northern tip and the only star to shine with a green hue.
As daybreak nears, the blazing light of Venus appears in the east, as if heralding the coming sun. While climbing no more than a dozen degrees above the southeast horizon, spotting this this morning star should be easy in the hour before sunrise.