Venus is third-brightest object in sky

Planet can be seen low in the sky in Central Oregon

Published Dec 11, 2013 at 12:01AM

Venus

Blazing brightly low in the early evening sky tonight, Venus, unmistakably brilliant, is located in the southwest about 16 degrees above the horizon at sunset. Sometimes called the morning or evening star, Venus is not a star; it is the second planet from our star, the sun. Named after the Roman goddess of love, it shines brilliantly in reflected light from the sun and is the third brightest object visible from Earth after the sun and moon.

Presently, Venus is a bit more than a third of an astronomic unit from us. One astronomic unit is the average distance between Earth and the sun, about 93 million miles.

The closer a planet orbits the sun, the greater its velocity and the shorter its orbital path. Consequently, Venus orbits the sun in 224.7 Earth days, while we travel around the sun in our year of 365.26 days.

Venus is about 87 percent of Earth’s volume and 82 percent of Earth’s mass, and is often called Earth’s twin. Surface gravity is nearly the same as we earthlings experience. Venus has no moon. However, any satellite circling Venus would be invisible to surface dwellers. A dense, opaque cloud system blankets the entire planet. The atmosphere is over 95 percent carbon dioxide. Features of the surface have been mapped in detail using satellite-borne radar. Although planet Mercury is even closer to the sun, Venus is the hotter of the two because the dense clouds trap heat and prevent it from radiating away into space.

First extensively investigated by the Soviet Union, their Venera series of probes (the Russian name for Venus is Venera) scored some amazing firsts. Venera 7, for example, was the first device to achieve a soft landing on another planet, touching down in 1970. Venera 9, in 1975, returned the first images from the planet’s surface. Conditions on Venus are extremely inhospitable with temperatures averaging 464 degrees Celsius (more than 860 degrees F).

— Kent Fairfield is a volunteer with Pine Mountain Observatory and a lifelong amateur astronomer. He can be reached at kent.fairfield@gmail,com. Other PMO volunteers also contributed to this article.