What is the cause of the tremendous heat on Venus?
Venus has a very strong greenhouse effect. A greenhouse effect
is when the gases in the atmosphere trap more of the Sun's heat. A
lot of carbon dioxide, a very dense atmosphere, and a thick blanket
of clouds help trap the sun's heat. The transfer of heat by
atmospheric currents means both the night and day sides are almost
the same temperature.
Venus is like this because it is closer to the Sun than Earth so
it is naturally hotter. On Earth, it is cool enough for water to
condense and form oceans, where carbon dioxide can be absorbed. On
Venus, water cannot condense in order to absorb the carbon dioxide
so all of it stays in the atmosphere.
The temperature is about 460 °C.