Posted on 09/21/2011 1:09:55 PM PDT by SeekAndFind
Dartmouth College theoretical physicist Marcelo Gleiser has an interesting essay this week which deals with the possibility of life around the universe and, more to the point, what such life might be like. It was spurred by the recent discovery of one of the most promising possible Earth-like worlds yet, orbiting in the “Goldilocks zone” of its parent star, where water could exist in liquid form. As more and more of these planets are identified, scientists will be focusing their search for possible forms of intelligent life in those regions of the galaxy.
But if life exists, Gleiser wonders, would it necessarily have advanced to a state of technological intelligence the same way it happened here on Earth? Dr. Gleiser thinks we might not want to get our hopes up too far. Many of his colleagues assume that the Universe is “just right for life” because it happened here, but we may be the exception to the rule.
The assumption here is that if physics and chemistry are the same then biology will develop. When we think alien life we are thinking in terms of Darwinian evolution via natural selection, which is a very good bet. Of course, we will only know for sure once we discover a sample of alien life, study its genetics, etc. But it’s hard to think that the very general principles set forth by Darwin won’t apply to other forms of life. If there are multiple life forms and limited resources, the rest will follow.
Of course, that says nothing of the particulars of possible alien life. A very clear distinction must be made between simple, unicellular life and more complex life forms. It’s hard to doubt that Earth is the only planet where life took hold. After all, we have seen how resilient it is here, with extremophiles defying our previously held assumptions of where life can thrive. However, there is a huge difference between simple life and complex life. Contrary to what many believe, evolution doesn’t lead to complex life forms: evolution leads to well-adapted life forms.
I’ve heard this argument made before and, as depressing as it may be, it carries a lot of weight. Some very well respected biologists have claimed that life on Earth only made the jump from what essentially amounted to little more than pond scum to more complex, multicellular forms through a rather remarkable and stressful series of events.
The theory, in short form, is that simple, unicellular life which thrives in a given climate has absolutely no reason to make the jump to something more complex and unlikely if the prevailing conditions are allowing it to succeed just fine as it is. A drastic change in environmental factors is required to challenge the organism and create the opportunity for something new and improved to adapt. But the catch is, if the environmental change is too drastic and harsh, the life form simply dies off and the process has to begin all over again. (Or have life disappear entirely.)
Should we develop the technology to get a really good look at any of these Goldilocks worlds, will we find ET hard at work building a rocket? Or even something as advanced as a cow? Or is it far more likely, as Dr. Gleiser seems to suspect, that we’ll find worlds covered in green slime which have dominated their environment and never found a need to advance further?
I have to agree with the professor that it is unlikely that there is sentient life out there. On the extremely rare occasion that we find life it will most likely be single cell organisms.
We went through this with the Rogue Waves for several centuries. The math says that every now and then it's possible to have a wave higher than average. Within those waves it's possible to have a wave several times higher than average. And, within those waves it's possible to have a wave over 1,000 feet high, or maybe even a mile high.
It has to be the same with life.
Seriously? There are whole galaxies that were created before ours even existed
I am thinking we are too immature to warrant alien visitation often.
It would be like us going to mars every day because we saw live ants there, and trying to interact with them.
After seeing some of the amazing structures built before modern history, and hearing all the ancient stores of ‘star people’ I think we have been visitted before many times.
Just nothing in recent history.
It’s a big universe- they can’t spend ALL their time here.
Oh and I think people who believe in ‘crop circles’ are morons.
***After seeing some of the amazing structures built before modern history, and hearing all the ancient stores of ‘star people’ I think we have been visitted before many times.***
Those visits are our progeny who have mastered the art of time travel.
bump for later read
All very true. There’s so much more involved with our existence here than the planet being in a “Goldilocks Zone”. Take away our Moon and Plate Tectonics, and we probably wouldn’t be here, yet we’d still be in the magical “Goldilocks Zone”. I’m sure Jupiter has kept us here longer than we otherwise would have been.
I 'believe' there are crop circles. Who or WHAT created them is another issue.
We know there are creatures thought not to exist on the ocean floor, and we have yet to discover all species alive on the surface of the Earth. Why could there not be creatures aloft in the layers of our atmosphere which we know nothing about?
Life is rare. It's rare in the solar system. It's rare even on Earth if something like a mass ratio is used to measure it (a few parts in 10 billion).
On the extremely rare occasion that we find life it will most likely be single cell organisms.
It's possible that life once existed on Mars and Venus. Simple life seems to appear within millions of years given the right conditions.
While there are probably an incredible number of planets in the Universe, the probability for conditions and the sequence of events needed for intelligent life is incredibly small.
We haven't yet risen up out of our ‘likely to nuke ourselves into oblivion any day now’ stage, and may well never reach the ‘the stars are our playground’ stage.
Heck, if the physics don't work out correctly there really isn't a ‘the stars are our playground’ stage.
Imagine also there may be a cosmic ‘booby trap’ waiting in Physics - you are the fist person in your intelligent tool using culture to discover the ‘Ygzog’ principle - unfortunately discovery of this principle released enough energy to reduce your planet to a cinder. Ooops.
Hmmmmmmm.....
Depends on what one means by LIFE.
Look up in the sky on a clear night. Every point of light you see is LIFE. Stars are the source of life. Without them, NO LIFE.
If one wants proof, then imagine what would happen to every form of life on Earth if the SUN were to go cold and dark.
Perhaps the ‘design’ of the Universe is on such a large scale to keep one TYPE of LIFE from encountering another. It is likely, given the huge differences in the FORM, that all we would do is try to destroy each other.
Whomever ‘designed’ the Universe was a pretty smart ‘chap’, and must have known EVERYTHING at the beginning.
I forgot who said it, but the gist was “Either we are alone, or we are not. Either way, it’s pretty amazing”
I don’t get this. Have scientists proven how life began? I think if they have we would not be speculating if there could be life on other planets. Just because a planet has the building blocks of life doesn’t explain how they’ve assembled themselves into life.
I mean if that we the case, wouldn’t houses and computers build themselves if their pieces were scattered about?
Yeah, I thought not.
Things developed the way they did here because of the resources that were available here and the conditions that existed during the ages.
Ample supplies of both water and land, average temp stable enough that the entire planet does not turn into a glacier or a desert, availability of chemicals (i.e. we live on Oxygen but our atmosphere is more than 70% Nitrogen), a moon which controls the tides in a reasonably orderly fashion.
Just because a planet exists which is approximately 93,000,000 miles from a sun like ours does not mean life must exist there. Those are only the first of many, many requirements for life to grow. If you believe in evolution, these were the things that, over millions and billions of years, enabled life to take hold and not die off.
Odds say there is sentient life somewhere else in the universe. Whole civilizaitons could have grown and died off over the billions of years of the universe. Odds also say any such life is so far away from us that we may never find them.
Looking for an Earth sized planet around a Sol sized sun is a good start but it’s no guarantee of success.
Unfortunately, because they were formed so early in the history of the universe, they lack the heavy elements that have to be formed by supernovas. Only the later starts (and planets) contain those heavy elements, as a result of the self-destruction of earlier stars. Without those heavier elements, it appears that life isn't possible.
Our sun appears to be a 4th-generation star, meaning that it benefits from heavy element creation in three prior generations of stars.
Could also be that our Jovial father has been trying to kill us all this time by slinging bullets from the Oort Cloud at our heads.
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