Water and water vapor are extremely rare on Venus due to its high surface temperature that can approach 758 K (900 °F). As the greenhouse effect becomes stronger on Earth, are we in any danger of transforming our own planet into a hellish place like Venus?Let us try to reconstruct the possible evolution of Venus from an earthlike beginning to its present state. By Wien's Law, at this temperature much of the energy is shorter than the CO 2 absorption at 4000 to 5000 nm, so it can escape and stop further heating of the surface.
Overall, the atmosphere of Venus is very dry; the absence of water is one of the important ways that Venus differs from Earth.The atmosphere of Venus has a huge troposphere (region of convection) that extends up to at least 50 kilometers above the surface (Figure \(\PageIndex{1}\)). Beyond its thick atmosphere, Venus’ axial tilt (aka. Venus presumably reached its current state from more earthlike initial conditions as a result of a runaway greenhouse effect, which included the loss of large quantities of water.Andrew Fraknoi (Foothill College), David Morrison (NASA Ames Research Center), Sidney C. Wolff (National Optical Astronomy Observatory) with many contributing authors.
Thick clouds at altitudes of 30 to 60 kilometers are made of sulfuric acid, and a \(CO_2\), which is greenhouse effect maintains the high surface temperature. As Venus got hotter and hotter, its oceans evaporated, eliminating that safety valve. Sunlight does not penetrate directly through the heavy clouds, but the surface is fairly well lit by diffuse light (about the same as the light on Earth under a heavy overcast). The highest mountain on Venus, Maxwell Montes, is 20,000 feet high (8.8 kilometers), similar to the highest mountain on Earth, Mount Everest. Venus has mountains, valleys, and tens of thousands of volcanoes. Textbook content produced by OpenStax College is licensed under a [ "article:topic", "runaway greenhouse effect", "license:ccby", "showtoc:no", "authorname:openstaxastro" ][ "article:topic", "runaway greenhouse effect", "license:ccby", "showtoc:no", "authorname:openstaxastro" ] But on Venus, the surface temperature is 460 degrees Celsius, day or night, at the poles or at the equator.
When we calculate how Venus’ atmosphere would respond to such effects, it turns out that even a small amount of extra heat can lead to increased evaporation of water from the oceans and the release of gas from surface rocks.This in turn means a further increase in the atmospheric \(CO_2\) and \(H_2O\), gases that would amplify the greenhouse effect in Venus’ atmosphere. The end result is that the surface heats to 730K - only at this high temperature is it possible for the energy to escape at the same rate it is absorbed by the surface. Sunlight does not penetrate directly through the heavy clouds, but the surface is fairly well lit by diffuse light (about the same as the light on Earth under a heavy overcast). There is evidence that this is just what happened to the water once present on Venus.We don’t know if the same runaway greenhouse effect could one day happen on Earth. The thick atmosphere of Venus produces the high surface temperature and shrouds the surface in a perpetual red twilight. Then we allow for modest additional heating—by gradual increase in the energy output of the Sun, for example. Venus rotates on an axis like earth but slower and in a direction opposite Earth's. These temperatures resemble something more of a raging fire due to an uncontrolled greenhouse effect which more than doubles the temperature on the planet's surface. This emission was detected for the first time by the spectrophotometers onboard the Venera landers as an increase in the measured spectra at wavelengths above 0.8 µm. The atmosphere on Venus is comprised mostly of carbon dioxide (COWater and water vapor are extremely rare on Venus due to its high surface temperature that can approach 758 K (900 °F). Venus may once have had a climate similar to that of Earth, with moderate temperatures, water oceans, and much of its \(CO_2\) dissolved in the ocean or chemically combined with the surface rocks. The predominance of carbon dioxide over nitrogen is not surprising when you recall that Earth’s atmosphere would also be mostly carbon dioxide if this gas were not locked up in marine sediments (see the discussion of Earth’s atmosphere in Earth as a Planet).Table \(\PageIndex{1}\) compares the compositions of the atmospheres of Venus, Mars, and Earth. The atmosphere on Venus is comprised mostly of carbon dioxide (CO 2) and a small percentage of the atmosphere is nitrogen.
Explain how the greenhouse effect has led to high temperatures on Venus The thick atmosphere of Venus produces the high surface temperature and shrouds the surface in a perpetual red twilight. With its surface pressure of 90 bars, the venusian atmosphere is more than 10,000 times more massive than its martian counterpart. On Earth, most of the \(CO_2\) is either chemically bound in the rocks of our crust or dissolved by the water in our oceans. In the atmosphere of Earth, sulfur dioxide is one of the primary gases emitted by volcanoes, but it is quickly diluted and washed out by rainfall.
The landscape is dusty, and surface temperatures reach a scalding 880 degrees Fahrenheit (471 degrees Celsius).