Atmosphere of Venus

The atmosphere of Venus is chiefly carbon dioxide in a concentration much higher than that found on Earth. Surprisingly, no evidence has been found for carbon monoxide, though ultraviolet light decomposes CO2 to form CO. The atmosphere of Mars is thought to be largely nitrogen (around °8%) and some carbon dioxide. 

Nave, Rod. The atmosphere of Venus, Georgia State University Web site. Available online. URL http //hyperphysics.phy-astr. gsu.edu/hbase/solar/venusenv.html. Accessed on March 10, 2008. 

Water can be found, in all three aggregate states, almost everywhere in the universe as ice in the liquid phase on the satellites of the outer solar system, including Saturn s rings and in the gaseous state in the atmospheres of Venus, Mars and Jupiter and in comets (as can be shown, for example, from the IR spectra of Halley s comet). The OH radical has been known for many years as the photodissociation product of water. 

Atmospheres are a natural consequence of the origin and evolution of planets. If planets are of sufficient size, they may have captured some nebular gas while they formed. Accretionary and radioactive heating can also release gases that were brought into the planet in solid carriers. The atmospheres of Venus, Earth, and Mars are composed of the same gases (C02, N2, H20, 02), but in markedly different amounts and proportions, reflecting their different evolutionary histories. For example, the rise of life on Earth... 

The Earth s oceans reveal an abundance of water that corresponds to —1/1000 of the planet s mass. Mars, too, once had liquid water that sculpted its surface, and water ice still resides at its poles and in its subsurface at high latitudes. The high D/H ratio in the atmosphere of Venus suggests that it once may have contained water in similar abundance to the Earth. Even Mercury, baking in the Sun s glare, appears to have water ice at its poles. The amounts of water in the terrestrial planets are modest, relative to the amounts of water in gas- and ice-rich planets in the outer solar system, but the importance of water for planetary habitability demands that we discuss how the inner planets got their water. 

The dense clouds in the atmosphere of Venus, which obscure the surface of the planet totally from our view, are evidently composed of a sulfuric acid aerosol. Why are such clouds possible on Venus but not on Earth (See Section 8.1.)... 

Fig. VIII—13. Temperature profile of the atmosphere of Venus. The surface corresponds to 6055 km from the center of Venus. (M) is the number of molecules per cm3. The surface pressure is 88 bars and the temperature is 750°K. Venus is covered with dense clouds (probably sulfuric acid droplets). After McEwan and Phillips (20), reprinted by permission of Edward Arnold Ltd.

Oxygen is the most abundant element in the Earth s crust and accounts for 23 % of the mass of the atmosphere. In fact, Earth is the only planet in the solar system with an oxidizing atmosphere. On Mars, oxygen provides only 0.15% of the atmospheric mass and in the atmospheres of the outer planets, oxygen is essentially nonexistent. In the hot atmosphere of Venus, the oxygen has reacted and is present mainly as carbon dioxide. In that form, and as certain other gaseous oxides, it contributes to the warming of the planet (Box 15.1). 

Two important applications of radiation to determine molecular structure—X-ray crystallography and magnetic resonance—were discussed in Chapters 3 and 5. In this chapter we will discuss a variety of other techniques. Microwave absorption usually forces molecules to rotate more rapidly, and the frequencies of these absorptions provide a direct measure of bond distances. Individual bonds in a molecule can vibrate, as discussed classically in Chapter 3. Here we will do the quantum description, which explains why the greenhouse effect, which overheats the atmosphere of Venus and may be starting to affect the Earth s climate, is a direct result of infrared radiation inducing vibrations in molecules such as carbon dioxide. 

Owen, T., Bar-Nun, A., Kleinfeld, I. (1992) Possible cometary origin of heavy noble gases in the atmospheres of Venus, Earth, and Mars. Nature, 358, 43-6. 

Schulze-Makuch, D., Irwin, L.N., and Irwin, T. 2002. Astrobiological relevance and feasibility of a sample collection mission to the atmosphere of Venus. ESA Sp. 518 247-252. 

The last two decades have seen some spectacular achievements in analytical science the placing of the environmental revolution on a sound basis by the routine determination of p.p.m. or p.p.b. levels of pollutants in the atmosphere, hydrosphere and biosphere the routine testing of athletes and race horses for traces of stimulants the remote analysis of the surface of the Moon and Mars and the atmosphere of Venus, etc. It has also been a period when the normal criteria for acceptable limits of impurities has dropped from the level of per cent to p.p.b., when non-destructive testing has become routine and when samples can be so small that even destructive methods of analysis scarcely have a deleterious effect on bulk of the material from which the sample is taken. In short, the nature of analysis has changed greatly. 

H2SO4 and S detected in the atmosphere of Venus by USSR Venera 8... 

There are several key differences between the atmospheres of Venus and Earth. The terrestrial atmosphere has a pronounced temperature inversion at the tropopause, which is the boundary between the troposphere and the stratosphere. This inversion is due to absorption of UV sunlight by ozone, but is absent on Venus, which has too little O2 (<0.3 ppmv) to form an ozone layer. The temperature gradient of —8Kkm in Venus troposphere is very close to the dry (i.e., condensation cloud free) adiabatic gradient. This is... 

Bezard B., DeBergh C., Crisp D., and Maillard J. P. (1990) The deep atmosphere of Venus revealed by high-resolution nightside spectra. Nature 345, 508-511. 

The atmospheric pressure at the surface of Venus is 90.8 atm. The Venusian atmosphere is 96.5% CO2 and 3.5% N2 hy volume, with small amounts of other gases also present. Compute the mole fraction and partial pressure of N2 in the atmosphere of Venus. 

The atmosphere of Venus contains carbon dioxide and nitrogen gases. At the planet s surface, the temperature is about 730 K, the total atmospheric pressure is 98 atm, and the partial pressure of carbon dioxide is 94 atm. If scientists wanted to collect 10.0 moles of gas from the surface of Venus, what volume of gas should they collect ... 

Composition oT atmosphere of Venus, Earth and Mars according to Lovelock and Margulis (1974)... 

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