If you look at the western sky just after sunset, or toward the east just before sunrise, you are likely to see what looks like a very bright star. In fact ancient peoples called it "Lucifer," which simply means "Shining One." We now know that this "wandering" star is actually the planet Venus.
The Babylonians, who first mention the planet, named it Ishtar, while the Romans called it Venus. Ishtar and Venus were goddesses of love and beauty so the names fit this shining planet.
Only the sun and moon are brighter than Venus in our sky. In fact, it's so bright that it's often mistaken for a UFO. When Earth and Venus get close to each other as they orbit the sun, the light radiated by this planet is so strong it can cast shadows.
Venus' brilliance results from its closeness to the sun and its covering of white clouds which strongly reflect the sun's light. The amount of light a planet reflects is called its "albedo" (Latin for Whiteness), and Venus' albedo is one of the highest.
In the early 1600s, Galileo saw that Venus passes through phases, just like Mercury and the moon, and that it is veiled in a thick cloud cover. These clouds prevented astronomers from seeing what the surface of the planet was like, so for many years it was thought that there might be life on Venus because it was similar to Earth in size and distance from the sun.
In the early 1950's scientist were able to use microwaves to penetrate the clouds. These microwaves show that Venus acts like a greenhouse. The cloud cover prevents the sun's rays from leaking back to outer space, so the surface temperature stays at 860 degrees - much too hot for life.
There is a theory that carbon dioxide from car exhaust and industrial pollution is creating a "greenhouse effect" similar to that on Venus. Some are afraid that if we don't stop polluting our air it will get so hot that Earth will become as lifeless as Venus.
