GREENHOUSE EFFECT

Spacecraft have also studied conditions above the ground. The atmosphere of Venus is 90 times heavier than Earth's. And with temperatures of about 890 degrees Fahrenheit (480° C), Venus has the Solar System's hottest surface.

Because Venus is closer to the Sun than Earth is, the sunlight it receives is twice as strong. After filtering through the clouds, the light is colored orange and is about as bright as on an overcast day on Earth.

When sunlight warms the surface rocks, they try to radiate the heat back into space at infrared wavelengths. But the heavy carbondioxide atmosphere is largely opaque to infrared light and acts like a thick blanket to keep the heat in. As a result, it is as hot at the poles of Venus as at the equator, and the night side is no cooler than the day side.