If, in our solar system, Earth had a twin, that sister planet was long thought to be Venus.
Venus is the second planet from the sun in our solar system, orbiting between Mercury and Earth. With Mercury, Venus comprises the “inferior” planets, those whose orbits fall entirely inside Earth’s. Venus is Earth’s nearest neighbor.
Venus is the “beauty” of the solar system. Saturn and his rings are more imposing, but Venus in takes the prize for comeliness, even though her stunning phases are visible only through a telescope. She is named for the Roman goddess of beauty and love, and is one of four objects in the solar system to bear a feminine name. All of Venus’ mountains and volcanic flows have been given the names of female mythological characters.
From Earth, Venus seems to follow the sun, never straying farther than 48 degrees from it, and the planet is often visible both when the sun rises and as it sets. This allows Venus to appear as both a morning and an evening star. Unique among planetary bodies, this characteristic of Venus’ caused the ancient Greeks to give the planet two names: “Hesperus” (from the Greek “Eosphorus,” “bearer of dawn”) when it was seen as the morning star, and “Phosphorus” (“bearer of light”) in the evening. The Greeks later came to accept the Babylonian theory that the two planets were one and the same, and called it “Aphrodite,” the name of the same goddess the Romans later worshiped as “Venus.”
The planet shares with Mercury a lack of moons; these two are the only planets in the solar system to have no satellites.
Venus’ orbit is nearly circular. Its “year” is 225 Earth days. Venus’ “day” – its period of rotation around its axis – is actually eighteen days longer than its year. This means that the planet turns the same face always toward Earth, and the interaction among its day, its year, and its inferior position yield Venus’ phases. The planet shares only with Uranus a retrograde rotation, which means that on Venus, the sun rises in the west and sets in the east.
Venus has no magnetic field, so compasses will not function there. Not that a human, even in a space suit, could stay alive long enough to take a reading: surface temperature is nearly 900 degrees Fahrenheit, and the atmospheric pressure is ninety times that on earth’s surface. In addition, Venus’ atmosphere is more than 90% carbon dioxide, with nitrogen and sulfuric acid making up the remainder. Oddly, while high clouds circle Venus at hurricane speed, at the surface air moves at the rate of a light breeze.
Seismic activities have shaped much of Venus’ surface. Some of her volcanic features are not seen on Earth, such as “pancake” volcanoes, which have flattened out instead of building the usual cone. The highest mountain on Venus tops seven miles. If placed in the Marianas Trench, a quarter-mile of it would be above the surface. The deepest Venusian valley drops only a mile below the planet’s surface.
Meteoric activity has also left its mark on the world, but it seems that most meteors break up in Venus’ thick atmosphere. There are often several small craters located close to one another where a large meteor broke up before impact. There are few large craters.
Venus was the first planet to be observed by a passing spacecraft: in late 1962, Mariner 2 passed within 22,000 miles of its surface. Since that time, many craft have flown over or orbited the planet; a few of the Soviet Venera series actually landing.
For many years, Venus was thought to be Earth’s “sister planet.” Closer acquaintance has rendered her little relation, but she remains, thanks to her mysterious phases, the beauty of the Sun’s family.
