Soviet and American unmanned probes that landed on the surface of Venus reported temperatures around 900 degrees Fahrenheit, day or night. On Venus, sunlight filters through the clouds and heats up the rocky surface. Instead, its energy is trapped in the atmosphere, adding to the heat provided by sunlight, and turning Venus into a gigantic furnace. Ordinary window glass behaves in much the same way on Earth as carbon dioxide does on Venus. Imagine a car parked in a sunny parking lot with the windows rolled up.
Sunlight gets through the windows, and warms up the car's interior.
Heat builds up inside the car, and when you open the door . . . It's hot . The nonprofit Astronomical Society of the Pacific has just released a slide set and short video from the Magellan Mission to Venus. An extensive booklet of background materials and detailed captions accompanies the set. Also included are short films of Earth and Mars, and Galileo spacecraft images of the Earth and the Moon.