Posted on 05/26/2004 9:09:24 AM PDT by presidio9
There could be life on the planet Venus, US scientists have concluded in a report in the journal Astrobiology. The existence of life on the planet's oven-hot surface is unimaginable.
But microbes could survive and reproduce, experts say, floating in the thick, cloudy atmosphere, protected by a sunscreen of sulphur compounds.
Scientists have even submitted a proposal for a Nasa space mission to sample the clouds and attempt to return any presumed Venusians to Earth.
"Venus is really a hellish place," said Professor Andrew Ingersoll, of the California Institute of Technology.
"If you could get through the sulphuric acid clouds down to the surface of Venus you'd find it was hotter than an oven. You could melt lead at the surface of Venus and there'd be no water."
But it was not always like that. Earth and Venus are in many ways sister planets.
"Current theories suggest that Venus and the Earth may have started out alike. There might have been a lot of water on Venus and there might have been a lot of carbon dioxide on Earth," Professor Ingersoll explained.
But all that was to change. On Earth, life in the oceans took in carbon dioxide and turned it into limestone. On Venus, 30% closer to the Sun, any oceans boiled away and the water vapour added to the runaway greenhouse effect.
Venus became our planet's ugly sister. Its make-over, which occurred billions of years ago, has left a surface where the pressure is crushing.
Arrested development
But, according to Louis Irwin of the University of Texas at El Paso, the changes on Venus may have been slow. "It may well have been Earth-like long enough for life to either emerge or be transported there," he said.
Once established, life would have adapted to every environment, just as it did on Earth.
Two years ago, Austrian scientists discovered bacteria living and reproducing within clouds on Earth. The same could have been true on Venus. Then, as the surface became hot and dry, the clouds might have become life's only refuge.
The Venusian clouds are high in the atmosphere, where the temperature and pressure are quite Earth-like. There is even water present, though it is in the form of concentrated sulphuric acid.
But we now know of organisms that thrive in very acidic environments on Earth.
"If you think about what life needs in a broad sense then the clouds of Venus might actually be a habitat where something could live," explained David Grinspoon, of the South West Research Institute in Colorado.
Another problem could be UV radiation from the Sun. But Dirk Shulze-Makuch, also at El Paso, thinks Venusian bacteria could make use of a natural chemical sunscreen there.
"When we looked at the composition of the atmosphere, we thought that sulphur compounds are actually an ideal sun block for microbes."
David Grinspoon speculates that the organisms might even have evolved ways of making use of the UV, much like Earth plants use visible light for photosynthesis.
"One lifeform's deadly radiation may be another lifeform's lunch," he added.
But will we ever know if there is truth behind the speculation? Louis Irwin and his colleagues have a proposal in with the US space agency, Nasa.
"We would send a probe to Venus that would drop probably a collector tethered to a balloon-like floating spacecraft, it would collect samples of the cloud droplets and then blast off from the Venusian atmosphere for return eventually to Earth."
And what are the chances of finding live Venusians? David Grinspoon is in no doubt: "If they're there, I think we will find them eventually."
I just KNOW there's a Uranus joke in here somewhere.
I consider no cosmos thread complete without one of those.
(Pinging the pinger of the science commentariat)
Cool link Martin-- I'll check it out.
Let the fools rush off to Mars. Venus will be worth something some day; Mars will never be significant in the history of the Solar System.
If we stay the course with GWB's commitment, I'd have to disagree. Which other planet would we be able to perfect terraforming on?
As far as Venus goes, it's almost impossible to imagination any human habitat on that planet.
See, that's where groupthink leads you. Mars is easy enough to get to. Venus is hard. But which one has the resources to make it worthwhile? Here's a secret: Mars is a barren desert. Mars could support a science colony, but otherwise nothing is happening. Some day someone will have the chance to opt for Venus, that will be the day the direction of human history changes.
Can you please cite evidence to suggest Mars' crust would not contain rare elements?
My ultimate point was that Mars will most probably be the second self-sustaining human planet, mostly becuase it is easiest to colonize. Can you argue otherwise?
I wrote off Mars decades ago. It wouldn't be useful as a base for asteroid mining. It could support a fair number of monasteries and science outposts, maybe a Plymouth Bay Colony now and then. But look at Venus! It could be cleaned up, spiffed up, and marketed as the New World, the thing America was supposed to be except this time for real. Venus is our twin, you know.
Understood, however, we must walk before we run. Mars will be our training ground. As far as cleaning and spiffing up Venus.....well, that sounds like a HUGE amount of terraforming. If we could normalize the atmosphere, what is the predicted surface temperature supposed to be?
The planet must be moved to an earth Lagrange point, and it must be provided with a moon. Mercury would be excellent in that role. Mercury is also a mining industry motherlode. Double bonus. Of course at this time we are unable to do much of anything on the moon, or even to capture an impact asteroid should one be coming our way. We don't have any capability to work in space, and we should get to work developing that capability. Venus is longterm, and we have a lot of technology to develop.
See? You've gone and proven my assertion! The majority of testing and development for those things will most probably occur via Mars colonization. Now, is that worthless?
Not saying the Mars plans are worthless, nor that Mars itself is worthless. Earthly monasteries need a place to go since earth has become inhospitable to certain subtle forms of life. Of curse, in the short term the moon and Mars are to be the main foci of action. However, the big tech is beyond that. Moving planetary bodies is so advanced that there are few clues as to how to proceed. It will be Mars and the moon for the rest of our lives anyway. After that Mercury and Venus. And after that something else, but I'll not worry about it. Venus sure looks nice sitting out there in the morning sky, which is not where it is at the moment. When you look at Venus, think real estate.
I'm not keen on terraforming. I suspect it would be a whole lot easier, and cheaper, to transform the Saraha desert. For getting work done in space, off-planet habitats seem like a more practical solution. That is, until we can get to other planetary systems where we might find more congenial planets.
Why so? Consider: gravity issues (atrophy)*, meteors, mineable materials (such as water, nitrates, etc.). Mars is pretty docile, comparatively.
Now, if you are discussing building one o' THESE babies,
I'll retract my argument completely. Well, only if I can shoot the lasers n' stuff. Beeyow! Zap!
*Yes, I know rotation can produce what we need, but that has inherent problems as well.
The gravity issue is overcome by spinning the environment. The best reason for using off-planet habitats for space work is the planetary gravity well. It costs a fortune to boost something into orbit. Once you're in orbit, however, you're "halfway to anywhere." It doesn't make sense to keep shuttling people between the surface and orbit.
Already addressed that (2 posts up, asterisk). As far as the gravity well, you are completely right. However, I cannot see mining all our our needed materials from asteroids. Ultimately, we are going to need to lift stuff up.
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