Venus water content

Let us compare the water content in the atmosphere of Venus with that in the terrestrial atmosphere ... 

Venus surface temperature range from 660 K (on the high Maxwell mountains) to 740 K (in the plains), the water content in the subcloud atmosphere is about 30 ppmv (Bailey, 2009 [15]). 

Therefore, additional proxies for water content on a planet must be investigated. A study of the surface mineralogy of Venus could provide another proof for the existence of large amounts of water during its early evolution phase. Under the presence of water, hydrous minerals formed on or below its surface. However, these minerals are unstable under the extreme temperature and pressure conditions on the surface (Zolotov et al., 1997 [376]). 

Johnson and Fegley, 2000 [172], argued that the mineral tremolite might indicate a higher water content on early Venus. On Earth, tremolite is found in basic rocks in contact with siliceous carbonate rocks. One possible reaction for the formation is ... 

Furthermore, life should be considered possible in aqueous environments that are extreme in their solute content, in their acidity or alkalinity, and in their temperature range, especially with ammonia as an antifreeze in low-temperature water-ammonia eutectics. The committee sees no reason to exclude the possibility of life in environments as diverse as the aerosols above Venus and the water-ammonia eutectics of Titan. It seems that life is less likely in more exotic solvents—such as liquid dinitrogen, liquid methane, and supercritical dihydrogen—but this conclusion is based on few data. 

Venus atmosphere is so dry that Earth-based and spacecraft measurements of the water-vapor abundance are extremely difficult. Historically, many of the in situ water-vapor measurements gave values much higher than the actual water-vapor content. However, reliable values are now available from several sources including the Pioneer Venus mass spectrometer, spectrophotometer experiments on Venera 11-14, Earth-based FTIR spectroscopy of Venus lower atmosphere on the nightside, and IR observations during the Galileo and Cassini flybys of Venus. 

The greenhouse effect is obviously demonstrated by our neighboring planets. Venus has an atmosphere of almost pure COj. In addition it is covered by white clouds. Its surface temperature is about 430°C. Thus Hquid water cannot be present on its surface. If present in earHer periods, also then with high contents of carbon dioxide, the radiation would have increased the surface temperature to levels at which water has vaporized. Water vapor also is an effective greenhouse gas, so the temperature increased by the combined action of water and carbon dioxide. Venus is thus a nightmare scenario of the danger with the greenhouse effect. 

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