Venus on April 21, 1999

Venus is named for the Roman goddess of love. But it would not be a very lovely place to visit. Venus has a very thick atmosphere compared to Earth. The atmospheric pressure at the surface of Venus is 90 times that at Earth's surface. Temperatures on the surface of the planet soar to more than 850 degrees F (450 degrees C) because of a runaway greenhouse effect. The light from the Sun that penetrates the planet's carbon dioxide rich atmosphere is absorbed by the surface, and then emitted as infrared heat. The clouds on Venus are largely hydrochloric acid and hydrofluoric acid. The atmosphere will not allow the infrared radiation to escape, and this results in scorching surface temperatures hot enough to melt lead. It makes summer time in Arizona seem like an artic vacation. Years ago, the Soviets sent a fortified space probe to land on the surface of the planet, but it lasted only an hour or so before the hostile environment did it in.

Venus orbits the Sun in about 225 days. But Venus rotates very slowly on its axis. In fact, Venus rotates the slowest of all the planets in our solar system. Venus takes 243 days to make one rotation. Venus rotates "backwards" as compared to the Earth and most of the other planets. Venus is nearly the same size as Earth. The planet's diameter is 12,102 kilometers at the equator, as compared to the Earth's 12,756 kilometer diameter. The surface gravity on Venus is 0.88 times the Earth's gravity. A person who weighed 100 pounds on the Earth would only weigh 88 pounds on Venus.

Venus is an inferior planet, meaning it's orbit lies inside our orbit. The inferior planets show phases, i.e., changes in their apparent shapes, like the moon as they move about the Sun. At the time this photo was taken, Venus was slightly more than half-illuminated. The clouds, however, reflect a significant amount of light. When Venus is visible, it is the brightest "star" in the sky. As an inferior planet, it never strays very far from the sun in our sky. It is always visible as either an evening star, or a morning star, depending on whether it is east or west of the Sun from our perspective. When this photo was taken, Venus was visible in the evening sky. Because the planet is always covered by thick clouds, you cannot see any surface features on Venus with a telescope.

This photo was taken with a Takahashi FS-128 refractor using eyepiece projection (5mm occular). The film was Kodak Elitechrome 100 slide film.

RA: 04h 37m 7.2s Dec: +23d 58' 01"
April 21, 1999
Photo by Sid Leach
Iola, Texas

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