Permanent Human Settlement of the Earth, Space and Ocean Frontiers

Friday, April 21, 2006


Venusian Vacation by Cyberpat
Ralph Buttigieg

Sydney NSW


ESA's Venus Express spacecraft is now safely orbiting Venus and beginning to send data to Earth. Dennis wonders why the Europeans are so interested in Venus. Well, I can't speak for ESA but I'll tell you why I am.
The greatest discovery of planetary exploration would be the discovery of life. The finding of even microscopic life outside Earth would be the find of the century. Most interest in the search of life has been centered on Mars. After all scientists did find the famous Mars meteorite a few years ago and astronauts will be visiting the Red Planet this century.

Venus may appear the last place to look for life. The first space missions revealed a hellish planet. The surface temperature is about 735K, hot enough to melt lead. Atmospheric pressure about 96 bar, similar to an ocean depth of one kilometer and the clouds contain sulfuric acid droplets not fresh water. No life can exist on the surface and the only visitors are likely to be robots.

However recent space probes have given us a more detailed picture of Venus and researchers are beginning to realise that conditions may be far more Earth like then previously thought. Not the surface, that will always be inhospitable but the cloud-tops are a different matter. There can be found the Venusian biozone. At the 50 km altitude the atmospheric pressure is one bar the same as Earth. The temperature goes down to about 40 deg C . Sydney summer beach weather. There's even water available in the form of sulfuric acid.

Scientists are beginning to take the possibility of Vensuian life seriously.

Our assertion that microbial life may exist in the Venusian atmosphere is based on the assumption that microbial life originated in an early Venusian ocean, or was brought in by meteorites from Earth or Mars. Life then adapted to the atmospheric niche when Venus lost its oceans," reported Dirk Schulze-Makuch, of the Department of Geological Sciences at the University of Texas at El Paso.

A few years ago Austrian scientists discovered bacteria that lived and reproduced in the clouds of Earth and some of the sulfur loving Earth bugs should feel at home in the Venusian sulfuric acid clouds.

Theres real evidence too not just speculation. Space probes have discovered the existence of both hydrogen sulfide and sulfur dioxide in the atmosphere. These compounds usually destroy each other and on Earth are renewed by anaerobic bacteria. However they can also be produced by volcanoes but curiously on Venus they are concentrated not at the surface were the volcanoes are but at the habitable zone level. Also the Venusian atmosphere contains carbon sulfide which although can be produced by volcanos, is also produced by life on Earth. Interestingly the lack of carbon monoxide is another indicator. Lightning and solar radiation should have produced lots of it but its not there. On Earth there are microorganisms that use carbon monoxide in their metabolism. Such bugs could explain the absence.

The Venus Express spacecraft primary mission is to explore the planet's atmosphere and the European researchers are well aware of the possibility of life and will be looking for more evidence.

As one of their scientist , Larry Esosito said:

.Fraser: I'd read that recently that something is blocking ultraviolet light in the high atmosphere and that could actually create an ecosystem that life could survive in?
Esposito: We know definitely that there are ultraviolet absorbers in the clouds, but we haven't been able to identify them, yet. The fact that they absorb sunlight could be the start of some biological ecosystem in the Venus clouds. That's pretty speculative at the moment, but very interesting to think of those possibilities. And Venus express will be observing in ways that could shed more light on that question, on Venus life at the presenttime.
Lets see what Venus Express turns up.