There are many geophysical similarities between Venus and the Earth. Average temperature is not one of them. Where the Earth has an average surface temperature of 14 degrees Celsius, the average temperature of Venus is 460 degrees Celsius. That is 410 degrees hotter than the hottest deserts on our planet.
The temperature on Venus does not vary like it does on our home world. It is 460 degrees day or night, at the poles or at the equator. Earth temperatures vary a bit because of the axial tilt of the planet. On Earth it is a tilt of 23 degrees in relation to the Sun;whereas, it is only 3 degrees on Venus. The atmosphere of Venus is also to blame for the heat. It is extremely thick and almost completely made of carbon dioxide. Carbon dioxide holds heat in(greenhouse gas), so the planet can not cool, even on the side that is not directly exposed to the Sun. The only respite from the heat on the planet is around 50 km into the atmosphere. At that point the temperature and atmospheric pressure are equal to Earth’s.
There is not a great deal of information to be had about the Venusian environs. The atmosphere has made visual observation impossible. It contains sulfuric acid clouds in addition to the carbon dioxide. These clouds are highly reflective of visible light, preventing optical observation. Probes have been sent to the surface, but can only survive a few hours in the intense heat and sulfuric acid.
What little knowledge that there is available came as a result of radar imaging of the planet. These images revealed a surface dominated by volcanoes. Many scientists believe Venus was resurfaced by volcanic activity 300 to 500 million years ago. There are at least 1,000 volcanoes or volcanic centers larger than 20 km in diameter. Lava flows have produced channels that extend for hundreds of km in all directions. The mixture of volcanic ash and the sulfuric acid clouds is know to produce intense lightning and thunder.
The temperature of Venus is not the only extreme on the planet. The atmosphere is constantly churned by hurricane force winds reaching 360 kph. The conditions on the planet make it easy to see why it is a barren, lifeless rock that has been hard to explore.
We’ve also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.