http://www.dailymail.co.uk/pages/liv...n_page_id=1965

"This remarkable discovery appears to confirm the suspicions of most astronomers that the universe is swarming with Earth-like worlds."

It can't be a surprise to anyone that there are Earth-like planets out there. And it wouldn't be much of a surprise to find that life abounds out there too.

Life must be generative and evolvative (coined words). It would make sense that life can be naturally generated when the right conditions exist, and once life gets a foothold that it would naturally evolve toward intelligence.

As a result of the discovery this first Earth-like exoplanet the arguments against abundant life in the universe are now much weaker. You have to agree that the balance has been shifted toward a more realistic expectation of intelligent life out there.

If you take that most of the stars are like our sun or smaller, most are binaries, that the estimated mass of our galaxy alone is in 300 billion solar masses range, and we only sampled the closests stars from us and we found over 200 planets and most of them around stars that no one expected planets around or closer then we expected them to be the stars. The chances there are planets the same size as earth is probably high well at least I think so.

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Maybe not "much of a surprise" to about 5% of the population.... It would certainly be a major, MAJOR finding.

I think the word you want is emergent. See At Home in the Universe [1995] by Stuart Kauffman.

From what I've read, there is no particular "direction" to evolution - except toward surviving and reproducing. Intelligence may help to survive but also may tend to cut down on reproduction.

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Everyone is entitled to his own opinion, but not his own facts.

Well at least on marriage ... no, just kidding. Where would I be without my "baby"?

Alright, emergent probably is better, but I like the sound of the two words, generative and evolvative when said together. What word would replace evolvative that would go with emergent? Maybe emergent and divergent?

I'm willing to bet "life" on other planets is exceedingly rarer than we would like to believe, and possibly non-existent within a finite universe (at least in terms of how we choose to define "life").

The problem with the Drake equation that's quite popular is that I think it's too broadly defined. Given how incredibily complex the basic building blocks of "life" is, the probability of the same biological mechanisms repeating even under the same environmental conditions is very, very slim.

Even the simplest single cell organism is incredibly complex. DNA is not a simple structure.....to suggest that every carbon molecular process elsewhere in the universe even under similar earth like conditions will coalesce into what will eventually be the helix structure of DNA>genes>single cell organisms (and beyond) is probably statistically far beyond the scope of the drake equation. That's not to say it's impossible, I'm just saying if all the variables were properly take into consideration you might find the chance of life occuring is statistically one of out a number possibly more than the number of stars in the known visible universe.

I'm not saying "life" doesn't exist elsewhere. I think our definition of life is too narrow and the type of life we're looking for we may never find. (carbon based, oxygen/water/temperature environmental prerequisites, the notion of single or multi cell organism, etc). Just because you have water & oxygen on a planet with ambient temperature & pressure as ours, doesn't mean life MUST form. All life on planet earth (plants and animals) can be traced back to a common ancestor. There isn't a single carbon based life form on our planet that's outside of that ancestral history, which would be quite common if these earth-like conditions were in fact a needed prerequisite. Likewise, who's to say Venus (or any other planet/location that we consider "hostile" in environment) can't be a catalyst for "life" in the future that utilizes a totally different set of environmental conditions?

It's okay. You don't need DNA to have life. The first life on earth wouldn't have used it. Basically you just need a replicator and that does not need to be complex.

One can only hope that truly intelligent life on other planets will hide from us for as long as possible.

:P

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After the first huge stars formed in our expanding universe and produced a complex of nuclei, the density of the matter that went into the building of subsequent stars was more and more diverse. Star formation from the dust expelled by early gaseous stars increased the likelihood of planet formation around new smaller slower burning stars.

Give me a star with a range of planets and some will be at the right distance to accommodate life. If every subsequent star that formed planets in this manner had a high likely hood of habitable planets, there could be more such planets than there are stars.

If you give me a habitable planet and billions of years I will “bet” on life emerging and diversifying.

Given the apparent likelihood of habitable planets around a higher than expected number of stars, and given trillions and trillions of stars in billions and billions of galaxies, and billions of years I am coming up with my own conclusions.

My bet is that life is far from rare in our expanding universe.

Given billions and billions of iterations of the repetition of life on planets with changing conditions that accompany the formation and development of hospitable environments, life will come, and life will adapt.

The migration of life across a universe like ours is not solely dependent on emergence originating in each habitable location either. The cataclysms that occur even in a quiet universe like ours will shatter bed rock and distribute the tenacious bacteria across any given distance given enough time IMHO.

MMM, tastes like chic.. er.. cabbage.

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"Without [natural selection], we reason, there would be nothing but incoherent disorder. I shall argue... that this idea is wrong. For, as we shall see, the emerging sciences of complexity begin to suggest that the order is not all accidental, that vast veins of spontaneous order lie at hand. Laws of complexity spontaneously generate much of the order of the natural world. It is only then that selection comes into play, further molding and refining. Such veins... have not been entirely unknown, yet they are just beginning to emerge as powerful new clues to the origins and evolution of life." [Stuart Kauffman, At Home In The Universe]

After 30 years of research, Kauffman shows that given a certain threshold level of molecular diversity, the emergence of a very primitive life form, or protolife (life being very difficult to define exactly), is practically inevitable.

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Everyone is entitled to his own opinion, but not his own facts.

If you're referring to carbon based life forms as ourselves, then you need more than just the "right" distance. Otherwise, the term "habitable" is purely subjective.

We aren't so sure how life began here in the first place. How can you confidently proclaim the same mechanisms will occur elsewhere without even first understanding properly our own origins?

Besides, you have a habitable planet right here to make your bet. Why aren't there any other unique "life" other than ourselves (ourselves being all animals, plants, microscopic life forms that all share a same common genetic structure). Let's say for a second you elliminate all DNA based lifeforms (virii included) on earth, what are you left with? Why hasn't "lightning struck twice" on our planet's long, habitable history?

I'm not disagreeing with you that there is likelihood of life elsewhere. What we disagree is just how likely. As I posted previously, I think if you modify the drake equation to take into account all variables that would cause the "spark of life" as we know/define it, you'll see the probability for likelihood plummet far more than what the original equation indicates.

I disagree. I don't believe given a set of conditions, life MUST come, like an inevitable chain reaction. Given a set of hospitable conditions, life MAY emerge and that is a huge "MAY" dependant on a set of variables that changes even under the same ideal conditions. This is why we don't see or have collective evidence of any other unique carbon based life forms on planet earth.

We would be better off trying to find signs of "intelligence" in the universe rather than try to define what biological life is elsewhere in the universe.

That may explain the link between Mars and Earth if life (whether current or ancient) is ever found there. Bacteria by itself however, are still complex organisms composed of genetic structures that share a common DNA link with all other life on planet earth. I still don't think you realize the enormous variables required that would bring rudimentary carbon based life into existence even under the same set of conditions.

Would you mind spelling out what the ATM idea in this OP is please?

I would bet on this too if given a planet similar to early earth. Sure I only have a sample size of one to work with, but since life appeared so early on earth I'd be willing to put money on it appearing on a similar planet if given billions of years. My hunch is that if the origin of life is astoundingly unlikely then we'd be living on a planet that is warmer, drier and perhaps a billion years older.

I'm trying to think of a suitable analogy for the reason there is no other unique genetic structures on earth.

The best I can think of is a sperm cell fertilizing an egg. Once this event happens - conditions in the egg change such that no other sperm is allowed to penetrate.

Perhaps once life got started - the toxic byproducts of consuming energy and eliminating waste made the earth inhospitable to any other unique genetic structures. Consider the oxygen cotastrophe as an example. Once life is started - the only things that can occur are variations on a theme.

Same with fertilization. We don't know exactly how that new life will grow and develop over the long term. The one thing we do know for certain is that the basic DNA signature will never change.

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I submit that life generates 'pollution', deadly to itself if the environment doesn't dillute and carry it away. While some life creates 'poisons' to beat down the competition or avoid, in general, there's always byproducts or removed toxins to a life form. Case in point, plant life would have poisoned itself with oxygen without oxygen consuming life forms (and fire). The same thing goes for animal life creating co2 but in this case, fire doesn't help. It's a symbiotic relationship between different forms of life that have different requirements for sustenance and have different sorts of waste.

While I don't really believe the life on earth formed on earth. In that 100 or 200 million yrs or so between the time life is known to exist and the great 'splat' that formed the moon and IMHO turned the earth into one big blob of molton mess surrounded by a blanket of co2 plus our atmosphere and probably with quite a bit of h2o vapor that there really isn't that much time for anything to really get formed. After all, things gotta cool down quite a bit for the surface to solidify again and the h2o to become liquid. And, there's a heck of a lotta co2 that needs permanent sequestering by inorganic means. Anyway - panspermia seems to make a bit better sense. Call it the not invented here syndrome.

However, it would seem Drake's eqn was made in a time where the concepts of astronomy were gradual slow events in an almost static ballet of the heavens. Inhospitable conditions in the realm of space beyond earth were qualified as vacuum, heat and cold (oh and maybe that pesky van allan belt up there just beyond the atmosphere). There was virtually no concept of transients - other than super novae which tended to be considered quite local in effect. Modern times has brought about an understanding of significant amounts of transients, including super massive ones, and radiation factors that one would possibly expect to virtually offer the universe a built in sterilization feature. Even the earth has virtually gone through some minor cycles that did severe damage to the existing life and we're likely out in the boondocks compared to the majority of stars and their potential planets.

It's interesting where those to conflicting facets leave us. Perhaps life formed in this solar system from venus before it turned into the easy bake oven we're familar with or perhaps from mars. The fact venus still has all that excess co2 or currently has that excess co2 makes one wonder although I think there are theories that think it was once an earth style planet before the sun's radiant energy output rose beyond what venus could handle. We have found recently meteorites evidently from mars containing what might actually be fossilized life forms - as announced a few years ago by the previous president and NASA. It would seem a panspermia mechanism exists.

Personally though, I'm still awaiting word on the discovery of intellegent life on earth. Even here, it seems to be a rather rare commodity and perhaps a rather transient one.

This is really a 'Life in Space' topic, or so it seems to me.
And as to how does life start on any particular planet? One thing it seems to require is vastly different conditions to those found on our world today. Over the last billion years or so, photosynthesis has changed our atmosphere into an oxygen rich environment; abiogenesis doesn't seem to happen in such an environment. That is why we don't see life emerging today on our world.

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It is weakly mentioned in the OP but what I want to express is that the discovery of an Earth-like exoplanet adds a data point to the position that life could be more likely and more widespread than previously expected.

It could be argued that such is not the case because the existence of habitable environments was not considered a rare circumstance anyway. Or it could be argued that the mere presence of habitable planets says nothing about the eventual inhabitation.

The OP made reference to the generation of life or as Cougar pointed out, emergence. The idea of mentioning emergence was to express the idea that if there are more habitable environments then there will be more occurrences of life emerging.

The OP made reference to the idea of an "evolvative" aspect to life that has emerged. The idea of mentioning evolution is to indicate the position that the more frequent the emergence of life is, the more frequent that life will evolve intelligence on the order of humans.

Therefore, with the discovery of an Earth-like planet it is more likely that intelligent life is more prevalent than previously thought.