Life on Venus

Eroica · #1 (**permalink**) 20-February-2005, 12:50 PM

Most of the speculation about extraterrestrial life in the Solar System seems to be centred on Mars and Europa, but I think Venus might be a better bet.

I know, the conditions on Venus today are hardly conducive to life as we know it. But there must have been a time in the early history of the Solar System when the planet would have been very much like the Earth. It's about the same size; it must have been cooler before it suffered a runaway greenhouse effect (if that's why it's so hot today); and the Sun wasn't always as hot as it is now.

So life could have evolved. And if there's one thing we know about life - especially simple microbial life - it's that it's very hard to eradicate it once it takes a hold. Here on Earth bacteria have evolved that can survive in extremely hostile conditions. Why not on Venus? Why could simple life forms not have continued to evolve as the planet's environment deteriorated, adapting themselves to ever harsher conditions?

I'm going to stick my next out and say that some form of microbial life is flourishing on Venus to this day.

cyswxman · #2 (**permalink**) 20-February-2005, 01:24 PM

I don't know. With a surface temperature about 900F, I would think that would effectively sterilize any microbial life, not to mention the sulphuric acid clouds.

Manchurian Taikonaut · #3 (**permalink**) 20-February-2005, 01:38 PM

Don't jump the gun yet, there are a few who still think its possible

scientists have found tough-organisms, extremophiles, hyperthermophiles, and very strong microbes...but we have no clues yet for life beyond Earth

However there is a real Against the mainstream idea but they who write about it have hope for it, just like those Current Life on Mars ideas
Its been covered in the news
Lifeon Venus Possible - check the cloud tops said Space dot com

http://www.space.com/scienceastronom...us_030211.html

RMH · #4 (**permalink**) 20-February-2005, 05:27 PM

The temperature, yeah, likely a problem. The highest temperature extremophiles on earth currently known cap out at approximately 230 F. However, they're still looking, and there's been at least one unconfirmed report of possibly archaebacteria in the middle of some 'Black Smoker' vents, at about 350 F.

The sulfuric acid rain - not so much of a problem. Ferroplasma acidarmanus is a iron sulfide eater that grows best at pH 0.7 (but can grow at pH 0.0 ) is just an example from here on earth.

So, I still think it may be possible to have something deep underground or cloud tops there.

Maddad · #5 (**permalink**) 21-February-2005, 06:25 AM

The problem with high temperature is that it denatures proteins and other organic molecules. It unravels them so they no longer have the same chemical properties that they had before because their hydrogen bonds break. When the temperature goes higher yet their other chemical connections break apart. Long before you got as hot as Venus is today, all these organic materials would be disassembled into simple blocks that wouldn't have the complexity for life.

If you're thinking that it would have been different in past millions or billions of years, you're right. It would have been hotter.

the_shaggy_one · #6 (**permalink**) 21-February-2005, 06:44 AM

Not really. The sun was less intense in the past. I think the sun is 40% more luminous now than it was when it was a brand new star. I thought Venus is supposed to have had liquid water and oceans and such for a long time after it had formed, but it was too hot and it all boiled into the atmosphere, then the hydrogen was lost to space as water molecules were obliterated by UV, leaving venus with very little water.

This is all supposed to have happened before the runaway greenhouse heated the planet to a gajillion degrees.

crosscountry · #7 (**permalink**) 21-February-2005, 01:50 PM

I would expect that the temperature rose so quickly on Venus that life wouldn't have any time to evolve. It's about time not temperature.

Remember the million monkeys and Shakespere?

Eroica · #8 (**permalink**) 21-February-2005, 05:41 PM

Quote:

Originally Posted by crosscountry

It's about time not temperature.

That is indeed the crux of the matter. How quickly did conditions on Venus become inimical to the appearance of life?

Anyone know what the current thinking on this question is?

Brady Yoon · #9 (**permalink**) 21-February-2005, 06:30 PM

Quote:

Originally Posted by Eroica

Quote:

Originally Posted by crosscountry

It's about time not temperature.

That is indeed the crux of the matter. How quickly did conditions on Venus become inimical to the appearance of life?

Anyone know what the current thinking on this question is?

I think it's around 1 billion years.

aurora · #10 (**permalink**) 21-February-2005, 08:09 PM

Quote:

Originally Posted by Brady Yoon

Quote:

Originally Posted by Eroica

Quote:

Originally Posted by crosscountry

It's about time not temperature.

That is indeed the crux of the matter. How quickly did conditions on Venus become inimical to the appearance of life?

Anyone know what the current thinking on this question is?

I think it's around 1 billion years.

Since it appears that Venus resurfaced itself roughly 800 million (if I recall correctly, number is off the top of my head) years ago, we cannot know what early Venus was like based on evidence from the current surface. Ideas on when, for example, Venus' water disappeared (assuming it was there to start with) would have to be based on lots of assumptions and extrapolations.

If there is any life on Venus today, the most likely place to look would be in the upper atmosphere.

Jpax2003 · #11 (**permalink**) 21-February-2005, 10:28 PM

Any chance that the poles are much cooler? Is it possible that the planet may be cooler at depth, for at least a narrow range?

aurora · #12 (**permalink**) 21-February-2005, 10:54 PM

Quote:

Originally Posted by Jpax2003

Any chance that the poles are much cooler? Is it possible that the planet may be cooler at depth, for at least a narrow range?

Doubtful about the poles. Note that Venus rotates very slowly, yet the night side is as hot as the day side.

I don't remember any projections of the subsurface temperatures, but I think if you want to propose life inside Venus, you'd have to come up with a way for life to exist without water.

Jpax2003 · #13 (**permalink**) 21-February-2005, 11:53 PM

Quote:

Originally Posted by aurora

Quote:

Originally Posted by Jpax2003

Any chance that the poles are much cooler? Is it possible that the planet may be cooler at depth, for at least a narrow range?

Doubtful about the poles. Note that Venus rotates very slowly, yet the night side is as hot as the day side.

I don't remember any projections of the subsurface temperatures, but I think if you want to propose life inside Venus, you'd have to come up with a way for life to exist without water.

Good point, if we can have advective transport to the dark side, then I suppose it would do the same to the poles. Do we know the wind patterns of Venus, are they latitudinally banded?

crosscountry · #14 (**permalink**) 22-February-2005, 05:35 PM

I believe they are. Remember the pictures with cloud bands in the shape of a V

this is the best I got on my hard drive

Venus doesn't differ by much reletively. It's like 650 and 750 K on dark and light sides respectively.

confused dude · #15 (**permalink**) 24-February-2006, 02:21 AM

quite frankly, i think that we cant judge life on othe planets. we know so little about our own planet. before we found the deep sea vents we had no idea that creacers could live on vens so why not venus

granolaeater · #16 (**permalink**) 24-February-2006, 10:08 AM

Quote:

Originally Posted by Eroica

That is indeed the crux of the matter. How quickly did conditions on Venus become inimical to the appearance of life?

Anyone know what the current thinking on this question is?

This link might help.

The main points for our discussion are:

Quote:

Originally Posted by David Grinspoon

Jim Kasting is the best in the business, and his models are state of the art. But the state of the art is not that good.
If you read Kasting's paper, there are these huge uncertainties in the time scale. He's had to make many simplifying assumptions to try and solve the problem of the loss of oceans on a planet like Venus. When you include all these assumptions, the real range of uncertainty in his model is longer than the age of the solar system. In other words, Venus could have lost its oceans in 10 million years, or retained them for longer than the age of the solar system.
...
We decided, and Jim Kasting agrees, that the major uncertainty in the models is the role of clouds. Kasting's models did not include clouds...
...
When we put in clouds in our model, we found that the clouds act to cool the planet significantly during that greenhouse phase. Temperatures are significantly lower.
...
If these results pan out, it might lead to the conclusion that liquid water on the surface of Venus lasted significantly longer. I can't put a precise number on it yet, but it may go from hundreds of millions of years to billions of years.

The article is from 2004. So back than the situation was quite unclear, but with a tendency to longer times with liquid water.
On earth life began 3.8 billion years ago. the formation of oceans and continental crust should have begun about 4.2 billion years ago. So everything that makes the venusian oceans last longer then about 400-600 million years should give hope that life developed in them.

For having life on Venus today, this early life would have had to be sophisticated enough to take the jump into the atmospheric clouds. This would have taken further time. But I think an ocean lasting between 1 and 2 billion years should sufffice.

ryanmercer · #17 (**permalink**) 24-February-2006, 05:07 PM

Quote:

Originally Posted by RMH

The temperature, yeah, likely a problem. The highest temperature extremophiles on earth currently known cap out at approximately 230 F. However, they're still looking, and there's been at least one unconfirmed report of possibly archaebacteria in the middle of some 'Black Smoker' vents, at about 350 F.

*nods* evidence exists of procaryotes living at temperatures as high as 115 degrees C (239 degrees F). In fact, cultures have been obtained that can be easily grown at this temperature in the laboratory. *nods* I can't remember the specific ones though. But yeah, nothing higher than that has been found to date.

granolaeater · #18 (**permalink**) 24-February-2006, 05:53 PM

Quote:

Originally Posted by ryanmercer

Quote:

Originally Posted by RMH

The temperature, yeah, likely a problem. The highest temperature extremophiles on earth currently known cap out at approximately 230 F. However, they're still looking, and there's been at least one unconfirmed report of possibly archaebacteria in the middle of some 'Black Smoker' vents, at about 350 F.

*nods* evidence exists of procaryotes living at temperatures as high as 115 degrees C (239 degrees F). In fact, cultures have been obtained that can be easily grown at this temperature in the laboratory. *nods* I can't remember the specific ones though. But yeah, nothing higher than that has been found to date.

On the cloud decks, 50 km above the surface, where an unknown UV-absorber can be seen, where unknown processes seem to destroy carbon monoxide and produce carbonyl sulfide, and non spherical cloud particles of unknown composition were detected, the temperature is about 70°C.
So, no, temperature is not a problem.

A real problem might be the scarcity of of elements like phosphorus, sodium, potassium, and calcium in the atmosphere. But perhaps ash from volcanic eruptions might help here.

Huevos Grandes · #19 (**permalink**) 24-February-2006, 07:02 PM

Quote:

Originally Posted by granolaeater

On the cloud decks, 50 km above the surface, where an unknown UV-absorber can be seen, where unknown processes seem to destroy carbon monoxide and produce carbonyl sulfide, and non spherical cloud particles of unknown composition were detected, the temperature is about 70°C.
So, no, temperature is not a problem..

Sounds plausible enough, but for the reason stated in the first part below:

Quote:

Originally Posted by granolaeater

A real problem might be the scarcity of of elements like phosphorus, sodium, potassium, and calcium in the atmosphere. But perhaps ash from volcanic eruptions might help here.

Has anyone tried to formally "debunk" or marginalize such a possibility yet ? The extremophile comparison work is relatively new, but I would have thought such an "evolved" form of bacterium (tiny, yet loft-capable spore, long dormant/growth phases, extreme temperature resistance, etc.) would have to have been initiated by a more archaic, less specialized, and less hardy species. Also, wouldn't these flying colonies need to be huge to be detected and isolated as UV-absorbing, and non-spheroid ?

granolaeater · #20 (**permalink**) 24-February-2006, 08:15 PM