The Backyard Astronomer
by Adam England
The second brightest object in the night sky (after the Moon) is the planet Venus. Records going back at least 5,000 years show human societies acknowledging that the “morning Star” and “Evening Star” were one and the same, traveling across the horizons as it circled the Sun. The Sumerians associated Venus with the goddess Inanna, who was unique in that she was the only deity who could traverse from the netherworld and back to the heavens. The Mayan calendar focuses on the movements of what the considered the three most important celestial bodies- The Sun, Moon, and Venus. Many eastern cultures refer to Venus by their respective literal translations of “Metal Star”, referencing the importance they placed on it as one of the Five elements.
With advancements in visual astronomy, we learned that Venus was a terrestrial planet, with thick cloud clover, rendering landscape observations impossible. While the early space race saw America aim for the Moon and Mars, the Soviet Union focused on the inner solar system, successfully exploring the planet with dozens of each flybys, orbiters, landers, and even the first off-earth balloons. All of this data, as well as continuing missions and discoveries, told us that Venus was very similar to Earth in many ways, and drastically different in others.
At about 90% the size of Earth, it is the closest in size of any planet or exo-planet we have yet discovered. Venus orbits the sun at about ¾ the distance Earth does, but rotates very slowly, completing a revolution once every 243 days. Due to a run-away greenhouse effect, Venus also has the densest atmosphere of the rocky planets. The air pressure on the surface is equivalent to 92 times sea level pressure on Earth, or about the same as 3000ft underwater. Clouds of sulfuric-acid hold in the Sun’s heat, with average temperatures above 867 °F. By all considerations, Venus is desolate, inhospitable landscape of volcanic activity, an example of what Earth could be like in a few million or billion years.
Recently, scientist used extremely powerful telescopes on Earth to analyze the Venusian atmosphere, detecting the chemical phosphine at 20 parts per billion. While phosphine can occur naturally in nature, it is only known to be produced in such quantities by organic processes. Without diving into a deep chemistry lesson, it suffices to say that we have no explanation as to how the phosphine would be there, except as having been produced by active anaerobic ecosystems, such as is the case with fermentation and deep sea organisms on Earth.
To catch a glimpse of our cosmic neighbor/twin during the month of October, look to the east in the hours before sunrise for the bright “Morning Star”.
If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at www.prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event.
The Backyard Astronomer 