Venus was a Roman goddess associated with love and beauty – an appropriate name for the most brilliant of the planets. The ancient Greeks knew this “star” by two different names. When visible in the evening sky, it was called Hesperus, but when it rose in the east before sunrise, it was named Phosphorus, a word that means ‘light-bearing’. Nowadays you’ll often hear Venus referred to as either the morning or evening star.
This weekend the planet returns to view for early morning sky watchers. If you’ve got a nice open horizon to the southeast, you should have no trouble spying the goddess about “one fist” held at arm’s length above the horizon an hour before sunrise. Venus will be nearly lined up with Spica, Virgo’s brightest star, and Saturn higher up. A pair of 8x-10x binoculars carefully focused and held with steady hands will reveal Venus as a thin crescent. Train them on Saturn as well. Though you won’t be able to resolve the rings themselves, if you’re sharp-eyed, the planet should appear slightly oblong. That’s because the ring plane extends out on either side of the planet giving it a slightly stretched appearance.
In the next week, Venus will climb steadily higher in the eastern sky at dawn as it moves out and away from the sun from our perspective on Earth. You’ll also be able to see its crescent slowly fill out just like the moon’s. Both effects are due to the changing geometry between our planet and Venus as it revolves around the sun.
Most of you already know that Venus’ shiny appearance belies a hellish world, once we drop below the planet’s perpetual cloud cover. It’s nearly pure carbon dioxide atmosphere is so dense, that the pressure a person standing on the surface would experience is nearly the same as 3300 feet under Earth’s oceans. The cloud deck on the dayside is about 12 miles thick and an excellent reflector of light just like Earth’s clouds. That’s why Venus is so bright to the eye.
The Russians landed a number of Venera spacecraft on the planet’s surface in the ’70s and ’80s and measured temperatures of 800 degrees. Venus’ greater proximity to the sun than Earth’s led to a catastrophic greenhouse effect, which heated the surface and atmosphere,Â boiling away any water it may once have had. Venus now has the hottest surface of any planet in the solar system. Throw in sulfuric acid rainfall, lightning and a barren volcanic landscape, you realize there’s much more to this planet than first meets the eye.
One last observing note for this evening: the Demon Star Algol will undergo one of its periodic fadings, as its larger, fainter companion star eclipses it tonight. It will dim from its normal 2.1 to magnitude 3.4 by 11:52 p.m. Central time. That means if you look anytime before 9, Algol will appear at its normal brightness.Â From 10:30 onward, the fading should become obvious. Click HERE for a chart and more information.