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.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.