Venus is the second planet from the sun and the closest one to the Earth. Except for the sun and the moon it is the brightest object in our solar system. It appears in the sky at dawn and dusk and for this reason, the ancient peoples believed it to be two separate stars in the sky. This gave rise to its having two names – Phosphorus, meaning morning star and Hesperus, meaning evening star.
ORBIT OF VENUS
The distance from Venus to the sun is about 67, 200,000 miles. Its orbital path around the sun is more circular than the other planets. It revolves around the sun once every 225 days at the speed of about 32 miles per second.
It rises and sets within three hours of the rising and the setting of the sun because of its close proximity to the sun. Its phases are similar to that of the moon, but unlike the moon it gives more light when it is crescent shaped rather than when it is full.
PHYSICAL CHARACTERISTICS
Venus is the planet that is most like the Earth in its physical make up. It is almost the same size with a radius of 3800 miles. It does have a slightly lower density, though, and has a mass equal to about 81% of that of Earth. It also has less gravity – about 89% of Earth’s gravitational pull.
ROTATION
The rotation of Venus is in the opposite direction to that of all the other planets, with the exception of Uranus. It spins very slowly on its axis, rotating only once every 243 days. A year on this planet consists of only about 2 days and 2 nights when compared with the elapse of time on Earth. This is due to the similarities in the time it takes to rotate on its axis and the time it takes to revolve around the sun. The surface of the planet faces the sun for the equivalent of 59 days and then it is away from the sun for another 59 days.
The rotation is also timed so that each time Venus passes through the Earth’s gravity, the same side of the planet faces the Earth. It is possible that the gravitational pull of the Earth does have an influence on the length of the day and night on Venus.
ATMOSPHERE AND TEMPERATURE
The atmosphere on Venus is extremely hot because of its short distance from the sun. It is made up of about 95% carbon dioxide with only trace amounts of water vapour. There are a number of layers of atmosphere as has been discovered by space probes, but very little is known about them.
The atmospheric pressure on Venus is about 100 times as great as that of the Earth’s surface and is far denser. This high density causes light rays to bend sharply, causing optical illusions.
At the surface the temperature is about 800F, which is hot enough to melt lead and zinc. Scientists believe this extreme temperature is due to a greenhouse effect as sunlight passing through the carbon dioxide in the atmosphere is absorbed in the ground and escapes only through wavelengths.
SURFACE FEATURES
Remote-sensing instruments have measured height distances on the surface of Venus in excess of 50,000 feet high. It appears that there are two mountain ranges, but the composition of the mountains is unclear because the high temperatures can easily melt rock as we know it. The surface is also believed to be like that of a desert because of the lack of water on this planet.
