Modeling Venus' Climate

In our solar system, no planet more closely resembles Earth than does Venus. Not only is it located in an orbit very near our own, it is also roughly the same size (with its radius of 6,051.8 km, only 326 km smaller than Earth¡¦s) and is composed of many of the same materials. Venus¡¦ planetary density, volume, and gravity are also close to Earth¡¦s, though they are slightly lower than our own. These facts have caused researchers to develop the theory that millions of years ago, both Venus and Earth formed from the same nebula in space, and had Venus ended up in E

On Earth, the greenhouse effect is much less severe than on the planet Venus, primarily due to the differing compositions of each planets atmosphere. On Earth there is a relatively insignificant amount of carbon dioxide, therefore the greenhouse effect is less intense. On Venus, however, the high concentration of CO2 causes the greenhouse effect to be relentless and magnified. Furthermore, scientists posit that if, in fact, Venus did at one point have surface water, when the temperature increased to the point where that water was evaporated, the vapor would enter the atmosphere and contribute even more to the greenhouse effect. This would create a vicious cycle wherein evaporating water causes temperatures to rise further, causing more water to evaporate, and so on. This perpetual cycle would have caused any past oceans to continually evaporate at increasing speeds. Although this cycle would eventually stabilize and reach an equilibrium point at which the planet of Venus would remain at a high temperature and pressure (with no surface water). The outcome of the greenhouse effect on Venus is a surface temperature of 737K with only 1% of the heat energy escaping into space.

Another interesting characteristic of Venus that has long puzzled scientists is the planet¡¦s unusual rotation. Like Uranus and Pluto, Venus rotates on its axis in the direction opposite that of Earth, meaning that the sun rises in the West and sets in the East. Venus also has the most circular orbit of all the planets in our solar system. Many theories have been developed to explain this phenomenon of retrograde rotation, but none have enough scientific evidence to be proven true. One theory, however, postulates that in Venus¡¦ early history, the planet was struck by another object in space, forcing its direction of spin to reverse. Another interesting contrast between Earth and Venus is that it rotates at an exceptionally slow rate. While Venus orbits the sun once every 225 Earth days, it only rotates once around its axis every 243 Earth days. This means that Venus¡¦ year is actually shorter than a single day on that planet.

In late 1962, the United States¡¦ Mariner 2 mission sent back the first scientific data about Venus, showing that its surface was about 425„aC (800„aF). In 1967, the USSR¡¦s Venera 4 mission became the first to be placed directly in Venus¡¦ atmosphere and return atmospheric data; it showed that the atmosphere was 90-95% CO2 and no N2 was detected. The pressure was measured at 75 bar (or 75 times stronger than that on Earth), and the surface temperature was read at 500„aC. Venera 4 was crushed by Venus¡¦ atmosphere before it reached the surface. One day after Venera 4 visited Venus, the United States¡¦ Mariner 5 atmospheric probe arrived at the planet and returned data that the atmosphere was 85-99% CO2. The 1969 USSR Venera 5 and Venera 6 atmospheric probes both returned data indicating an atmosphere composed of 93-97% CO2, 2-5% N2, and less than 4% O2. In late 1970, the USSR attained the first successful landing of a spacecraft on another planet (which was Venus),

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Pioneer Venus, Earth Venus, Soviet Union, USSR Venera, , Laboratory California, USSR¡¦s Venera, East Venus, CO2 Venus¡¦, CO2 N2, greenhouse effect, venus¡¦ surface, venus¡¦ climate, venus¡¦ atmosphere, cloud cover, surface temperature, earth days, water vapor, planet venus, planet¡¦s surface, cover reflects 85%, axis 243 earth, venus¡¦ thick cloud, rotates axis 243, 243 earth days,