carbon dioxide and sulfur dioxide—and they also contain large amounts of corrosive sulfuric
acid!
Figure 25.11: This ultraviolet image from the Pioneer Venus Orbiter shows thick layers of
clouds in the atmosphere of Venus. ( 2 )
The atmosphere of Venus is so thick that the atmospheric pressure on the surface of Venus
is 90 times greater than the atmospheric pressure on Earth’s surface. The thick atmosphere
also causes a strong greenhouse effect, which traps heat from the Sun. As a result, Venus
is the hottest planet, even hotter than Mercury. Temperatures at the surface reach 465oC
(860oF). That’s hot enough to melt lead!
Volcanoes
Venus has more volcanoes than any other planet. Planetary scientists have estimated that
Venus has up to 100,000 or even a million volcanoes. Although these volcanoes contributed
carbon dioxide in the past, most of the volcanoes are now dead. Venus doesn’t seem to
have tectonic plates like the Earth’s. It’s surface is covered with dead volcanoes and ancient
craters.