Posted on 01/07/2002 8:54:10 AM PST by RightWhale
http://www.spacedaily.com/news/life-02a.html
A Universe Of Life: Maybe Not
by Karl Hill
Las Cruces - Jan 7, 2002
This vast universe surely holds plenty of worlds where life can flourish, right? Don't bet on it, says New Mexico State University physicist Slava Solomatov.
The more scientists learn about the conditions that make life possible on Earth, the more they realize how complex those factors are -- and how a relatively small change in one condition or another could have rendered the planet uninhabitable, Solomatov said.
"It's a very finely tuned system," he said. "Some of the factors are well known, but we still don't know what all the factors are."
Solomatov has a key part in a NASA-funded astrobiology research project aimed at better understanding the origin of life on Earth and the conditions in which life might be found elsewhere in the universe. The five-year, $4.9 million grant supports the work of a dozen researchers, headed by a team at the University of Washington.
The scientists come from a variety of fields, because life requires much more than water and the right mix of elements to survive and evolve into higher forms.
Solomatov's part of the project focuses on the role of plate tectonics -- the geologic process that results in the shifting of Earth's continental and oceanic plates. Only in recent years have scientists recognized the importance of plate tectonics in maintaining Earth's long-term temperature stability, through global recirculation of carbon dioxide from the planet's interior into the atmosphere, he said.
"Because carbon dioxide is a greenhouse gas, it helps to keep our planet warm," he said. "Of course, too much of it is not good, but without this cycle over the centuries the temperature would drop and you might have the 'Snowball Earth' scenario."
Plate tectonics also provides diverse geological environments, like mountains, which promote biodiversity, Solomatov said.
No other planets are known to have plate tectonics, although some may have had the feature earlier in their evolution, he said.
Whether plate tectonics might be essential to the development of higher forms of life is unknown, but Solomatov's theoretical modeling of the complex processes aims to shed light on a number of key questions, including: What planetary conditions allow for the formation of plate tectonics? Are oceans necessary for plate tectonics? When and how did plate tectonics begin on Earth?
The question of life on other planets, or even the habitability of other planets, has long captured our imagination, but we tend to be biased in our assumptions, Solomatov said.
"We think this is normal and there should be planets all around the universe like Earth," he said. "The more I work in this area, the more I realize the chances really are very slim."
It's not enough for a planet to be the right size, to have water, and to be located the right distance from a star of the right size. Without the giant planet Jupiter as a neighbor, and without our moon, Earth might not be the living planet that it is, Solomatov said.
Jupiter has protected Earth from too many cataclysmic asteroid collisions, he explained -- but on the other hand, a neighbor much larger that Jupiter would not allow formation of an Earth-like planet in the first place. Similarly, our moon is just the right size to help stabilize Earth's spin axis and, as a consequence, the Earth's climate. With a bigger moon or no moon at all, a planet similar to Earth in other respects might not sustain life.
The list of critical factors grows longer as scientists learn more.
"At the moment there are two camps of believers," Solomatov said. "One believes in the 'Rare Earth' hypothesis and the other thinks life is smart and can adapt to extreme conditions."
The "Rare Earth" hypothesis, which takes its name from a book by University of Washington scientists Peter Ward and Don Brownlee, holds that microbial life might be common in planetary systems, but advanced life is rare.
If pushed into one camp or the other, Solomatov would choose the "Rare Earth" believers.
"We don't have enough data yet but all the evidence we have now points out that the Earth is a very special place," he said. "Maybe we should take better care of our planet."
At any rate, my hat is off to NASA. As far as government agencies go I think its one of the better ones. No one in their right mind would mess with a country that can put men on the moon and land robots on Mars.
I have recently changed my opinion of what we will find "out there." If we find intelligent life, and that is a BIG if, we may not even be able to recognize it as intelligent or maybe not even as life.
Stumbling across an earth like planet that harbors intelligent life, that is close enough to us to find it, is remote in the extreem.
I have always been of the opinion that we are alone in the universe. I have been badly outnumbered by those who see billions of stars and think the odds favor intelligent life beyond earth, so I was surprised to see the book "Rare Earth" get even a polite reception.
I think NASA should not be spending money looking for ET, and I would rather they had a different mission such as opening space to development. Mainly that would involve cheaper transportation and a favorable legal environment.
If we stumble across ET sometime, fine, we will deal with it. Until we serendipitously find ET, it is a weak mission to go looking.
And is partly responsible for the fact that they have made themselves so perilously close to institutional extinction. A "search for ET life" is a mission, all right. the only problem is, it's a mission with a low probability for success.
The book Rare Earth actually claims that bacterial ET life is probably quite common -- Ward and Brownlee claim that advanced, intelligent life is rare (let alone technologically advanced life), mostly because the planetological factors responsible for the creation and evolution of the Earth appear to be unlikely (not impossible) to be reproduced elsewhere.
NASA's mission should be to explore the universe with people and machines. Period. Leave the "search for life" stuff to the Saganite Planetary Society and other California flake groups.
Absolutely. But look what Columbus found while trying to locate a shortcut to the Orient? I think finding life is a great goal, but it need not be the only focus of exploration. I'm sure we're going to discover many fascinating things that we never expected.
Flake groups? ROFL! I know I am in good company. :)
Be nice.
*ducking under my desk for flame protection*
Sigh! If I must.
ROTFLMAO!! :) Art Bell time!
How did the Ancient Mariner say it?
All, all alone on an empty sea!
All, all alone in a vast, lifeless universe.
Which is more frighteening? A universe teeming with life
or one where we are the ONLY life forms?
Space tourism is the only market I foresee, but it's still too expensive and the training is still too rigorous for most people.
Humankind is currently balanced at that point in it's history. Stay tuned.
Achieving satori doesn't actually change the world.
To sort of quote a favorite story character:
If the world stopped every time one of us had a bad day, we would all be floating in space.
Life developing on a planet with different characteristics will adapt to that planets conditions.
Mr. Whale, Does satori lead to nirvana?
Next Q. Is nirvana just nothingness rather than eternity?
That sounds like something that Rod Serling might've said at the end of a Twilight Zone episode. Good question, too.
Looks like more evidence for the "anthropic principle."
The spaceships are in great condition and ready to go, we just don't have the Americium to fuel them. ;)
Ten to the twentieth is a mighty big number.
I would agree. The question for me has never been "does life exist elsewhere". The question for me has always been "what is the probability that we would cross paths with life that existed elsewhere in the universe”.
The universe is basically empty. The entire universe is virtually devoid of any matter. Look to any point in the sky and then extend that line to the end of the universe. The odds are enormous that you will never encounter an object in that path even though there are billions of stars. This is because the universe is spread over time and space.
The odds are staggering against ever encountering another life that is within one or two billion years of our own? We may not even be able to recognize life if it were too many billions of years ahead or behind us.
In my mind the universe may be teeming with life but the odds that we would ever cross paths is indeed remote in the extreme.
I'm amazed at all the rare-earthers that have sprung up. The last time I argued this on FR I was shouted down.
My guess is that the radio civilization will last a couple hundred years, being replaced by who knows what -- entangled quantum particles, perhaps? So the window for crossing paths via SETI is brief indeed. I suspect that live, biological humans will never travel to the stars, although our descendents might.
On the other hand, several civilization fronts could have passed through our solar system already. Come and gone. How would we know?
All it will take is one more...
He is being nice :) , and he is in very good company. ;)
One factor is that Sagan is gone and silent. The pendulum has swung about as far as it is going to. It's still way over on the ET side, but more "we might be alone" voices are being heard recently.
There are 100 billion trillion stars in the Universe. If every star has one planet that could sustain life, then we have 10 to the 25th power possible life planets. Problem is that the odds of life are estimated to be 10 to the 32nd power (some estimates has high as 128th). So your one planet is earth.
After multi billions of years, in the unimaginable vastness of space, WE are the only thing the universe has been able to produce.
A very scary, and very sad postulation, isn't it ?
Suddenly you've recalled images of the the old Twilight Zone episode: "To Serve Man" featuring the guy who played Jaws in the James Bond films as the hungry alien. Happy new year VR !
Would you share your references, please?
Not really. On the aesthetic level this points out that since we appear to be it for intelligent life [people and dogs and ravens, etc.], we ought to feel a sense of importance.
Which is to say, if we don't go forth and multiply throughout the universe, we are not doing as we were instructed. We also need to stop fighting over this ball of dirt. Drop that RPG and get to work!
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