Other than its atmosphere, Venus is so similar to Earth that it is sometimes called Earth's sister planet . Its diameter and mass are almost identical to Earth's. Venus' atmosphere traps these longer wavelengths so they cannot escape into space. The trapped heat builds up , so the planet grows hotter and hotter. The same thing happens in an automobile on a hot day.
Sunlight comes through the windows and warms the inside of the car, but the heat is trapped.
Even though Venus' orbit brings it closer to Earth than any other planet, its blanket of clouds kept much of Venus a mystery. The first exploration of Venus by radar was in 1962. It revealed that Venus spins backward on its axis . If you could stand on the surface of Venus, and if you could see the Sun through the cloud cover, it would rise in the west and set in the east. Space probes have revealed that the atmospheric pressure at the surface of Venus is 90 times that of Earth's .