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What Are 10 Facts About Venus?

Often called Earth's sister planet, Venus is the closest of Earth's celestial neighbors. A great deal is known about Venus, even though man has never actually visited the planet. Virtually all of this knowledge is a direct result of images taken from telescopes and information garnered from unmanned space shuttles.

Equatorial Diameter
- The diameter of Venus at its equator is 7,521 miles. Earth's equatorial diameter is 7,926 miles, only 402 miles larger than Venus's. This size similarity is another reason Venus has been dubbed Earth's sister.
Orbital Period
- Because Venus is closer to the Sun than Earth, the time it takes for Venus to complete one orbit is significantly shorter than the time it takes for the Earth to complete its orbit. One year on Venus, as defined by the orbit, is a little more than half as long as one Earth year. This is equal to 225 Earth days.
Rotational Period
- It takes Venus 243 Earth days to rotate one time. What this means is that a single day on Venus is longer than a single year on Venus (225 days). Venus also rotates in the opposite direction as Earth.
Mass
- Venus' mass is 4.869 times 10 to the 24th kg. In the English system, this translates to 10.730 trillion trillion (as in a trillion trillions) pounds. This is .81 times the mass of the Earth.
Density
- Venus is very similar to Earth in terms of planetary density. Planetary density is basically a measure of the amount of material in the planet in relation to its overall size --- the equation for density being mass divided by volume. The density of Venus is .9 times the density of Earth.
Moons
- Venus has no moons. Venus and Mercury are the only two planets in the solar system without a single moon. Jupiter, by contrast, has more than 60 known moons.
Composition
- The core of Venus is very similar in composition to Earth's core, with a central iron core beneath a molten rock mantle.
Atmosphere
- Venus has a rocky surface covered by thick clouds containing sulfuric acid. The atmosphere is mostly composed of carbon dioxide. Carbon dioxide traps heat, thus resulting in surface temperatures of upwards of 900 degrees Fahrenheit.
Distance From the Sun
- Venus's average distance from the Sun is more than 67 million miles. This is 26 million miles closer to the Sun than Earth.
Appearance
- After the Sun and the moon, Venus is the brightest object that can be seen from Earth. Because Venus is brightest in the morning and in the evening, it has been called both the Morning Star and the Evening Star.

Astronomy