Planetary Geology:

The Volcanism of Venus

Report by

RAdm. RM Wey

OSR: SFS – SFC

The surface temperature of Venus is a blistering 460° Celsius, and an atmosphere comprised mostly of carbon dioxide, the air pressure on the surface is more than 100 times that of earth. Put another way, it is more an ocean than an atmosphere, with its gaseous sulfur compounds [along with what little water vapor there is] the surface is pelted with sulfuric acid.

Until the mid 90’s of the 20^th century, the surface of Venus had remained an enigma, shrouded by that very atmosphere. Through the use of Radar, Venus’ surface was shown to be a world racked by volcanic activity of near epic proportions. Along with this were added computer simulations as a means to determine the cause of Venus’ fate.

Unlike earth, there is no evidence of tectonic movement on Venus. Yet its surface denotes patterns suggestive of a once more water-laden world. Due to its proximity to the earth, the likelihood that Venus encountered icy bodies from outside the solar system [as did earth] was sufficient enough that a study was done. Research into this possibility determined that the ratio of deuterium to ordinary hydrogen was some 150 times the terrestrial value.

It was concluded that, at ‘some point’, Venus possessed far more water and lost it. One possibility was that, as water vapor [the hydrogen and deuterium, which are chemically equivalent,] drifted into the upper atmosphere, Ultraviolet Radiation from the sun ‘destabilized’ the water vapor into it component parts. Because hydrogen is lighter, it would have escape into space more readily, and thus the amount of deuterium increased.

Thereby arose another question: ‘Why Venus…and not earth?’ The answer lie in the proximity of Venus to the sun. With solar energy greater on Venus, its distance to the sun only some 67 million miles, added water vapor would further heat the atmosphere as its components were broken down. This process would further transport the bulk of the planets’ water into the upper atmosphere and ignite a runaway greenhouse effect.

Another condition that existed on Venus was the tremendous volcanic activity. During the primordial era of Venus’ evolution, the stresses of gravity by the sun constantly tore as its surface. Adding to the volatile soup that was its atmosphere this volcanic activity injected greenhouses gasses nearly 100 fold.

Initially, this worked in Venus’ favor, reducing the surface temperature to around 100° Celsius. But over time the clouds were lost as breakdown of the water vapor continued. It is estimated that this took about 200 million years. As the clouds thinned, more solar radiation reached the surface, raising its temperature. Eventually, the volcanic activity slowed, but did not cease [as is evident by the lack of large numbers of craters on its surface].

However, by then the atmosphere of Venus was as we see it today, a seething soup of sulfuric compounds poisonous to known life forms. A cauldron of glowing rocks which is reminiscent of Dante’s ‘Inferno’.

It is a place gone mad, and but for the grace of God, our planet could have met such a similar fate. Further research on this subject will be provided when it becomes available.