Venus

During the "Golden Age of Science Fiction" in the 1930's and 40's, Venus was a frequent setting for space adventure stories. After all, cloud-covered Venus is nearly the same size as Earth and it's only a little closer to the Sun than our planet is. Readers and writers alike fancied Venus as an enticing safari planet -- a steaming world-wide jungle filled with unknown and exotic creatures. Nowadays we know better, thanks to a parade of U.S. and Soviet spacecraft that visited Venus dozens of times between 1961 and 1997.

Venus is indeed warm, but more so than early sci-fi authors suspected. The surface temperature is ~860 F (460 C) -- hot enough to melt lead! The air is thick and steamy, too. The atmospheric pressure is about 90 times that of Earth. And the steam .... it's sulfuric acid, a corrosive mist that floats cloud-like through Venus's 96% carbon dioxide atmosphere.

Carbon dioxide is a greenhouse gas that traps infrared radiation beneath Venus's thick cloud cover. A runaway greenhouse effect is what makes Venus even hotter than Mercury! The clouds also hide a forbidding terrain, strewn with craters and volcanic calderas. There are no rivers, lakes, or oceans on Venus -- like Mars, Venus is bone dry.

If you were deposited on Venus by some unscrupulous space-tour company, you would immediately suffocate, melt and be crushed. Which might happen first is debatable, but it hardly matters. Venus is an awful vacation spot no matter how you arrange the itinerary. The best way to see Venus -- surely one of the most hellish worlds in the solar system -- is from afar.

Venus is frequently mistaken for a bright star, an airplane, or even a UFO. Indeed the planet is probably the most-often reported Unidentified Flying Object! But if you peer at Venus for more than a few seconds it's easy to see that it must be a planet. Venus doesn't twinkle like a star, nor does it move rapidly across the sky as an airplane or a flying saucer might.

Why is Venus so bright? Although it's not the largest planet in the solar system, Venus is usually the one nearest to Earth. Furthermore, Venusian clouds -- the same ones that hide Venus's fiery surface from inquisitive astronomers -- are excellent reflectors of sunlight. As much as 72% of the light that shines down on Venus is bounced back into space.

Like the Moon, Venus has a full range of phases. It can be "Full" when Venus is on the far side of the Sun, "New" when Venus is between the Sun and Earth, and a crescent at points in between.

Courtesy of NASA

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Average Distance From Sun

• Kilometers: 108,200,000
• Miles: 67,000,000
• Astronomical Units: 0.723

Length of Year: 224.7 days

Length of Day: 243 days 0 hours 25 minutes (Retrograde)

Average Orbital Speed

• Kilometers/Second: 35.03
• Miles/Second: 21.77

Equatorial Diameter

• Kilometers: 12,100
• Miles: 7,518
• Earth=1: 0.949

Mass (Earth=1): 0.815

Volume (Earth=1): 0.855

Mean Density (Grams/Cubic Centimeter) Water=1: 5.25

Surface Gravity (Earth=1): 0.88

Escape Velocity

• Kilometers/Second: 10.3
• Miles/Second: 6.40

Temperature Extremes

• High Celsius: 477°
• High Fahrenheit: 891°
• Low Celsius: -33° (Cloud Tops)
• Low Fahrenheit: -27° (Cloud Tops)

Atmosphere (Principal Gases): Carbon Dioxide (97%)

Number of Known Satellites: 0

Eccentricity of Orbit (Circular Orbit=0): 0.007

Inclination of Equator (To Planets Orbital Plane): 177.3°

Oblateness of Planet: 0

Orbital Inclination: 3.4°