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Achilleus
2012-Dec-17, 08:44 PM
Assuming that extraterrestrial life is fairly common (as I believe), isn't it possible that intelligent life is just as common. Isn't it possible that intelligent life, I.E. humans, are the natural process of evolution. A vast amount of species have been destroyed through mass-extinction, isn't it possible that intelligent life would develop on most planets to be able to respond to extraterrestrial events, terrestrial disasters, or other mass extinction disasters.
On earth after every major mass extinction, the next generation of species grows more intelligent. Maybe this increase in intelligence is an adaptation to be able to survive through mass extinctions.

Rhaedas
2012-Dec-17, 08:51 PM
Those are a lot of assumptions based on one sample. After every mass extinction, life didn't have to start over from single cell form, so the pattern of more intelligent might not really mean much, other than life is persistent.

ASTRO BOY
2012-Dec-17, 08:53 PM
You make some interesting points.......
I believe life is common and Intelligent life less common, but with the numbers involved still meaningful.

Achilleus
2012-Dec-17, 08:55 PM
True, but it seems in order for life to survive, at least on earth, through mass extinction a species can only take two routes intelligence (humans) or mass reproduction (bacteria). Therefore assuming that extraterrestrial species are forced to endure the same catastrophes as earth, they would have to take 1 of these 2 routes.

Colin Robinson
2012-Dec-17, 10:05 PM
Unless there is someone out there planning those mass extinction events, surely you'd expect random differences?

Random differences would mean that some planets with abundant life would experience fewer mass extinction events than here. So evolution happens in a different way. As it might have here on Earth, if the dinosaurs had never been wiped out.

Random difference may also mean some planets get mass extinction events are so severe that they wipe out everything living at the time, or at least everything larger than an amoeba. As might have happened to Earth, if the asteroid that killed off the dinosaurs had been somewhat larger and/or faster.

For this reason I doubt very much that planets where intelligence has evolved will turn out to be just as common as those with life in general.

I'm more inclined to agree with Astro Boy.


You make some interesting points.......
I believe life is common and Intelligent life less common, but with the numbers involved still meaningful.

Achilleus
2012-Dec-17, 10:25 PM
Of course you would expect random differences but any other planet that had life would surely experience mass extinctions, and if life could survive through those mass extinctions, as earth has, should not life adapt to defend itself against such events. If you take humans or Neanderthals for example, the level of intelligence far surpasses the need for reproduction


Unless there is someone out there planning those mass extinction events, surely you'd expect random differences?

Random differences would mean that some planets with abundant life would experience fewer mass extinction events than here. So evolution happens in a different way. As it might have here on Earth, if the dinosaurs had never been wiped out.

Random difference may also mean some planets get mass extinction events are so severe that they wipe out everything living at the time, or at least everything larger than an amoeba. As might have happened to Earth, if the asteroid that killed off the dinosaurs had been somewhat larger and/or faster.

For this reason I doubt very much that planets where intelligence has evolved will turn out to be just as common as those with life in general.

I'm more inclined to agree with Astro Boy.

IsaacKuo
2012-Dec-17, 10:29 PM
Assuming that extraterrestrial life is fairly common (as I believe), isn't it possible that intelligent life is just as common. Isn't it possible that intelligent life, I.E. humans, are the natural process of evolution. A vast amount of species have been destroyed through mass-extinction, isn't it possible that intelligent life would develop on most planets to be able to respond to extraterrestrial events, terrestrial disasters, or other mass extinction disasters.
On earth after every major mass extinction, the next generation of species grows more intelligent. Maybe this increase in intelligence is an adaptation to be able to survive through mass extinctions.
Most of the above is entirely possible; even plausible, but intelligence does not seem to be an adaption to survive mass extinctions here on Earth. (Maybe elsewhere, it's the rule, but in that case Earth seems to be an exception.)

Here on Earth, the way evolution works is that species evolve to adapt to current conditions, including recurring events. These events do not necessarily have to be frequent enough to occur within a single individual's lifetime. An important example is the co-evolution of various grasses and chickens. Some grasses evolved to try and starve out chickens/rodents by waiting many years to produce seeds--and then to produce so much so quickly that the normally supported population can't eat them all. Chickens/rodents co-evolved to be able to reproduce like crazy to take advantage of those brief windows of opportunity. This example is important because the resulting chickens had characteristics useful for humans to exploit, of course.

Anyway, the problem with mass extinctions is that they don't happen very frequently here on Earth. The time between such extinctions is so long, that there's little or no benefit to adapting to them. A slight head start after a mass extinction is overwhelmed by the slightest penalty between them.

However, I do recall a theory that humans may have evolved intelligence as a response to dealing with frequent "little" extinctions--frequent environmental changes. If conditions are generally changing frequently, then specialists are at a disadvantage compared to generalists, or species which can more flexibly change more quickly. I don't know how scientific this theory is, or how well supported it is, but it at least sounds plausible.

MaDeR
2012-Dec-18, 05:29 PM
A vast amount of species have been destroyed through mass-extinction, isn't it possible that intelligent life would develop on most planets to be able to respond to extraterrestrial events, terrestrial disasters, or other mass extinction disasters.
You know what survives best extincions? Microorganisms, especially underground. No intelligence required.


On earth after every major mass extinction, the next generation of species grows more intelligent.
Do you have any support for this claim? It is very... how to say it... bold.


Maybe this increase in intelligence is an adaptation to be able to survive through mass extinctions.
Nope. They are too rare and too omnicidal.

Paul Beardsley
2012-Dec-18, 09:55 PM
Assuming that extraterrestrial life is fairly common (as I believe)

Why do you believe it?

If you see a closed egg box (six pack, not see-through) with no context clues, do you "believe" there are three eggs in it and three empty compartments? Or do you simply accept that the number of eggs in the box is between zero and six?

The great thing about science is that you don't have to believe. And if you encounter a variable of unknown value, you can accept that the value is exactly that - unknown - and will remain so until experiments or observation provides data.

As for your other statements, I would agree that the development of intelligence is a natural process of evolution, but that doesn't mean it's an inevitable result.

Cougar
2012-Dec-19, 02:34 AM
Assuming that extraterrestrial life is fairly common (as I believe), isn't it possible that intelligent life is just as common.

I'd say no. The history of "intelligent" life on earth is way shorter than the history of life on earth. And how are you defining intelligence, anyway? Remember we're talking about life across the universe.


Isn't it possible that intelligent life, I.E. humans, are the natural process of evolution.

That is the mechanism at work here, yes; however, if you were to run that process over again here on earth, or if a similar earth-like planet out there somewhere was now undergoing that evolutionary process, I daresay the resulting lifeforms are likely to be demonstrably different than us earthly human animals....

As I recall, others here have pointed out that there would probably be some significant similarities, as well, with which I'd have to agree.

Demian
2012-Dec-19, 03:30 AM
"Intelligent" life in the realm of evolution is bound to self destruct. On earth, human beings' "intelligence" has caused us to separate ourselves from nature... therefore removing the needed the "survival of the fittest" effect that Darwin proposed pushes evolution forward. Instead, we've build nuclear bombs with our intelligence and we cannot seem to shake that old bugger... our animal nature... which makes us beings of greed, lust, pride, etc... etc... which are the cause of so much destruction in our world. I would assume that the same effect would occur on other planets in terms of life within this realm of space and time. However... we definitely know that there are boundaries in our universe where all our equations break down for matter. (For example... at the speed of light or at the even horizon) At the speed of light, distance becomes "0" and time becomes "0" for an object that reaches those speeds. Matter can never come close to those speeds because no matter how fast matter travels... light will still be traveling at its constant "c" relative to that object. On the other hand, at the event horizon, distance is also "0" and time is also "0." No more equations. They all break down. Perhaps there are beings that are made of energy within these realms that have been with us all along... for the final stage of evolution... becoming a being of energy yourself. How do we get there? How can we just BE? How do we get there? I like this idea... and for some reason... I think it's true.

TooMany
2012-Dec-19, 04:36 PM
As I recall, others here have pointed out that there would probably be some significant similarities, as well, with which I'd have to agree.

Good examples are the similarity of an octopus eye to a human eye and the wide variety of species which have independently evolved wings to fly. Life in an alien system similar to our own, may resemble life here. We cannot expect a duplication, but we can expect the emergence of similar forms. Plants, fish, birds, insects, legged animals...

primummobile
2012-Dec-19, 05:53 PM
"Intelligent" life in the realm of evolution is bound to self destruct. On earth, human beings' "intelligence" has caused us to separate ourselves from nature... therefore removing the needed the "survival of the fittest" effect that Darwin proposed pushes evolution forward. Instead, we've build nuclear bombs with our intelligence and we cannot seem to shake that old bugger... our animal nature... which makes us beings of greed, lust, pride, etc... etc...

Why are we bound to self-destruct? We aren't just the bad things. Our intelligence also gives us plenty of things other animals don't have, like self control.


I would assume that the same effect would occur on other planets in terms of life within this realm of space and time.

Why would you assume that? How many intelligent species do you know of that have destroyed themselves?


However... we definitely know that there are boundaries in our universe where all our equations break down for matter. (For example... at the speed of light or at the even horizon) At the speed of light, distance becomes "0" and time becomes "0" for an object that reaches those speeds. Matter can never come close to those speeds because no matter how fast matter travels... light will still be traveling at its constant "c" relative to that object. On the other hand, at the event horizon, distance is also "0" and time is also "0." No more equations. They all break down. Perhaps there are beings that are made of energy within these realms that have been with us all along... for the final stage of evolution... becoming a being of energy yourself. How do we get there? How can we just BE? How do we get there? I like this idea... and for some reason... I think it's true.

What idea do you think is true? Because time stops at c that we will one day become "energy beings"? How in the world do you make that leap? I thought you just said we were going to self-destruct.

Cougar
2012-Dec-19, 05:56 PM
"Intelligent" life in the realm of evolution is bound to self destruct.

This is a very bold assertion, the exact opposite of which could just as easily be asserted.

primummobile
2012-Dec-19, 05:56 PM
Good examples are the similarity of an octopus eye to a human eye and the wide variety of species which have independently evolved wings to fly. Life in an alien system similar to our own, may resemble life here. We cannot expect a duplication, but we can expect the emergence of similar forms. Plants, fish, birds, insects, legged animals...

I made a very similar argument last summer and it was greeted with great hostility.

Hlafordlaes
2012-Dec-19, 10:02 PM
I made a very similar argument last summer and it was greeted with great hostility.

Don't see why you should have been. I rather agree we are likely to see life forms that remind us of analogues on Earth, as per your quote of TooMany, if we ever do see any. Sensory organs respond to the same physical phenomena and really ought to show convergence; wing-things for gases, appendages for land, fin-things for liquids, gas sacs for air or water environs, etc.

Paul Beardsley
2012-Dec-19, 10:31 PM
Don't see why you should have been. I rather agree we are likely to see life forms that remind us of analogues on Earth, as per your quote of TooMany, if we ever do see any. Sensory organs respond to the same physical phenomena and really ought to show convergence; wing-things for gases, appendages for land, fin-things for liquids, gas sacs for air or water environs, etc.

I would argue that we shouldn't be surprised if we did see such things - which is not the same as saying we should expect to see such things.

R.A.F.
2012-Dec-19, 10:42 PM
I made a very similar argument last summer and it was greeted with great hostility.

Could you post a link to that post, please...I'd like to examine it in context.

filrabat
2012-Dec-20, 12:02 AM
If you ask me, even complex ecosystems are at least fairly rare across the galaxy, given that a lot of things have to be sufficiently right for a planetary system to host an actual gaian world.

*Star of the right mass

---too small and cool, and it reduces the prob that any world will be in the habitable zone (cooler stars have narrower habitable zones, however you define it).
---too large and it won't exist for long enough to allow life to evolve on any world present (in fact, the radiation may be so powerful it keeps planets from forming at all)

*Planets of the right size

-- too small and it can't sustain either the tectonic activity to recycle gases and mineral from the atmosphere to the interior
-- too large and it'll attract a lot of hydrogen and helium in ever-increasing amounts as long as dense areas of those two gases remain availiable. This turns the planet into a gas giant.

* Sufficiently stable orbits

-- even if the orbit is centered in the habitable zone, too eccentric an orbit means too hot in its local summer and/or too cold in its local winter to sustain life.
-- gas giants spiraling in toward its parent star can prevent any planet worthy of the name from existing in the habitable zone.

And that is the minimum conditions. Some even say a large moon is necessary to sufficiently stabilize the axial tilt wandering through time.

All this is merely just enough to get a microbial ecosystem started. Add to that the fact that it took 4.6 billion years for our planet to develop us, and you're looking at pretty big odds as it is. If there are any intelligent civilizations in the galaxy, then the closest one we would recognize as an intelligent civilization is likely 10s of thousands of LY away. If there are any civs any closer, they may be so far in advance of us that we may not even recognize them as a civ.

whimsyfree
2012-Dec-21, 07:10 AM
If you ask me, even complex ecosystems are at least fairly rare across the galaxy, given that a lot of things have to be sufficiently right for a planetary system to host an actual gaian world.

*Star of the right mass

---too small and cool, and it reduces the prob that any world will be in the habitable zone (cooler stars have narrower habitable zones, however you define it).
---too large and it won't exist for long enough to allow life to evolve on any world present (in fact, the radiation may be so powerful it keeps planets from forming at all)


The Sun seems to be unusual in some respects. For example, it is an outlier in the rotation period - activity period plane. The significance of this is unclear.


*Planets of the right size

-- too small and it can't sustain either the tectonic activity to recycle gases and mineral from the atmosphere to the interior
-- too large and it'll attract a lot of hydrogen and helium in ever-increasing amounts as long as dense areas of those two gases remain availiable. This turns the planet into a gas giant.


The former probably applies to too-massive planets too. The latter may not be a problem for rocky embryos that form inside the ice line because light gases don't last long there.



* Sufficiently stable orbits

-- even if the orbit is centered in the habitable zone, too eccentric an orbit means too hot in its local summer and/or too cold in its local winter to sustain life.
-- gas giants spiraling in toward its parent star can prevent any planet worthy of the name from existing in the habitable zone.

And that is the minimum conditions. Some even say a large moon is necessary to sufficiently stabilize the axial tilt wandering through time.


Water delivery is a another issue. If a rocky planet forms well inside the ice line, where does it get water from? A popular theory is that Earth got its water from impactors that originated in the outer solar system. These icy bodies formed an early massive debris disk that was destabilized by Jupiter. How likely is this to happen? So far there is no confirmed Jupiter analog and indications are that such are rare. If it does happen, how likely is it that the amount of water will be just right, leaving a planet that is not too wet and not too dry?

IsaacKuo
2012-Dec-21, 05:16 PM
*Star of the right mass

---too small and cool, and it reduces the prob that any world will be in the habitable zone (cooler stars have narrower habitable zones, however you define it).
My idea of "habitable zone" is different from the traditional one, because I feel we should include candidate planets/moons which have subsurface oceans.

My thinking is that Earth life demonstrates non-photosynthetic ecologies around deep sea vents and cold seeps. Furthermore, the abiogenesis theory I find most plausible posits life originally emerged in such environments:

http://www.nature.com/news/how-life-emerged-from-deep-sea-rocks-1.12109

Also, sputtering of water ice molecules is a demonstrated mechanism for generating oxygen in ice covered moons. Taken together, I feel this means icy moons/planets with subsurface oceans should be considered candidates for complex aerobic life. (There actually has also been a recent discovery of complex anaerobic life, but as I understand it anaerobic life is still considered to be pretty limited in size.)

Thus, my own personal idea of "habitable zone" would include places where Europa-like worlds could exist. This potentially includes any place that isn't too hot, for worlds with sufficient internal heating (radioisotopes and/or tidal heating, perhaps from a collision formed moon).

For this idea of "habitable zone", small colder stars have bigger zones. Sun-like stars are actually not so good, because my idea of "habitable zone" makes a big deal of tidal heating. Relatively bright stars like the Sun might make planets too hot for liquid water, if the planet is close enough for tidal heating to power the biosphere. On the other hand, maybe it's not so hopeless for hot bright stars...if a planet is close enough to be 1:1 tide locked, then the dark side could be covered in water ice, along with subsurface liquid water oceans.

-- too small and it can't sustain either the tectonic activity to recycle gases and mineral from the atmosphere to the interior
Tidal heating could power tectonic activity in very small planets/moons. But below a certain size, there simply isn't enough internal pressure to support liquid water conditions. Small asteroids and comets may be plausibly ruled out.

-- too large and it'll attract a lot of hydrogen and helium in ever-increasing amounts as long as dense areas of those two gases remain availiable. This turns the planet into a gas giant.
While this is true, it seems like gas giants tend to have lots of moons. We don't know this to generally be the case, of course, but it's what we expect for now. These moons seem to be too small to be "Earth-like", but they're good candidates for subsurface ocean life.

All this is merely just enough to get a microbial ecosystem started. Add to that the fact that it took 4.6 billion years for our planet to develop us, and you're looking at pretty big odds as it is. If there are any intelligent civilizations in the galaxy, then the closest one we would recognize as an intelligent civilization is likely 10s of thousands of LY away.
It's a plausible theory, but we have a very wide range of plausible theories, given the paucity of data to work with.

ASTRO BOY
2012-Dec-21, 07:51 PM
As I mentioned early on in the piece in response to the opening post, life should be relatively common throughout the galaxy/Universe, Intelligent life less common for many valid reasons.
But what defines Intelligence?...and to what extent would that Intelligence advance that species technologically speaking.
Say an advanced species evolved in the Oceans of Europa.....How much technology and how advanced would there technology be taking into account they are confined to their Oceans. They would probably never master flight of any kind, no computers/Internet, phones TV etc.
What I'm asking is we generally measure Intelligence by technological advancement, but the process of technological advancement seems to be aligned by the evolutionary path a species was lucky enough to take. We each have two arms and two legs and have learnt to walk upright. We are able to grasp and think which seems to have helped us in our technological advancement.

But a species say like a Dolphin or an Elephant could theoretically have the same brain capacity/Intelligence as us but due to their evolutionary path they are limited to what they can achieve.
A Dolphin cannot grasp or manipulate....an Elephant cannot walk upright.
How do we classify Intelligence in the insect world, say with ants and bees etc......Their Intelligence is undeniable and their structures and ability to work in large groups have seen them out last many extinction events.

I hope I have put my thoughts clear enough and conveyed the problem with defining Intelligence with regard to any future contact with ET life.

IsaacKuo
2012-Dec-21, 09:50 PM
Say an advanced species evolved in the Oceans of Europa.....How much technology and how advanced would there technology be taking into account they are confined to their Oceans. They would probably never master flight of any kind, no computers/Internet, phones TV etc.
This is a popular theory, but I don't buy it. Basically, it boils down to the idea that fire is required for advanced technology, and that fire is impossible for aquatic creatures to develop. I don't buy it on either count.

First off, there's a lot of interesting chemistry and metallurgy in the oceans; we just aren't as intimately familiar with it because we are not oceanic creatures. I find it interesting that there are numerous animals with inate electrical senses and even electrical generation capabilities--but they are all aquatic. I could imagine that advanced aquatic aliens might find it implausible for land creatures to develop advanced technology, since they can't sense or generate electricity.

Second, aquatic creatures could use fire. They can burn fires on floating platforms, such as platforms supported by ice. They could have plentiful natural fuel in the form of methane ices, as well as fuels more familiar to us (oil, blubber, etc). In the case of a Europa style subsurface ocean, the ice "roof" will still trap pockets of air, so floating platforms are still possible.

As for the availability of manipulators--there are plenty of oceanic creatures with sophisticated manipulators. Trilobites, decapods, and cephalopods had sophisticated manipulators. It just so happens that none of these really had the smarts to go along with the manipulators, except for the cephalopods. But cephalopods are cursed with a life cycle which prevents them from passing knowledge from parent to child. Without social learning, it's hard to imagine they will leap from merely being very clever to developing advanced technology.

whimsyfree
2012-Dec-22, 12:08 AM
As I mentioned early on in the piece in response to the opening post, life should be relatively common throughout the galaxy/Universe, Intelligent life less common for many valid reasons.
But what defines Intelligence?...and to what extent would that Intelligence advance that species technologically speaking.
Say an advanced species evolved in the Oceans of Europa.....How much technology and how advanced would there technology be taking into account they are confined to their Oceans. They would probably never master flight of any kind, no computers/Internet, phones TV etc.
What I'm asking is we generally measure Intelligence by technological advancement, but the process of technological advancement seems to be aligned by the evolutionary path a species was lucky enough to take. We each have two arms and two legs and have learnt to walk upright. We are able to grasp and think which seems to have helped us in our technological advancement.

But a species say like a Dolphin or an Elephant could theoretically have the same brain capacity/Intelligence as us but due to their evolutionary path they are limited to what they can achieve.
A Dolphin cannot grasp or manipulate....an Elephant cannot walk upright.
How do we classify Intelligence in the insect world, say with ants and bees etc......Their Intelligence is undeniable and their structures and ability to work in large groups have seen them out last many extinction events.

I hope I have put my thoughts clear enough and conveyed the problem with defining Intelligence with regard to any future contact with ET life.

That might be a theoretical issue but we are not going to have any near future contact with extrasolar life other than by remote communications, unless they show up here (in which case their intelligence will be manifest). Therefore the sort of life that is of practical interest is the sort that might be emitting powerful electromagnetic radiation that we can detect. The useful output is advice to the SETI people on where they should point their radio telescopes and the operational definition of intelligence is something like "can produce detectable modulated radio signals distinguishable from noise and natural (inorganic) processes".

That largely rules out life on panthalassic worlds, life under thick ice sheets, and life in rocks (but possibly not pure energy beings1 (http://cosmoquest.org/forum/showthread.php/140294-Study-about-Aliens?p=2090691#post2090691),2 (http://cosmoquest.org/forum/showthread.php/140362-Intelligent-Life-Common-Across-Universe?p=2090057#post2090057)). It means life on planetary surfaces and above. It means looking for stars with planets suitable for the evolution of intelligent surface life.

Frank Merton
2012-Dec-24, 05:37 PM
When someone announces an earth-mass planet at one AU from a solitary G class main sequence star, what will we do?

Luckmeister
2012-Dec-26, 12:29 AM
When someone announces an earth-mass planet at one AU from a solitary G class main sequence star, what will we do?

Spectral analysis, if it's close enough.

Point our SETI searches at it.

Wish we had FTL travel.

Cougar
2012-Dec-26, 01:38 AM
If you ask me, even complex ecosystems are at least fairly rare across the galaxy, given that a lot of things have to be sufficiently right for a planetary system to host an actual gaian world.

Rare, yes; as you say, a number of things have to be "in the right range." But the galaxy is so freaking big, with so many stars, it seems likely there must be at least several life-bearing planets, maybe hundreds or thousands....

Frank Merton
2012-Dec-26, 06:01 AM
• Spectral analysis, if it's close enough.

• Point our SETI searches at it.

• Wish we had FTL travel.In other words, not much beyond getting excited and watching it. The real usefulness of finding such planets is that it will give us an idea of how common or uncommon Earths may be.

swampyankee
2012-Dec-26, 06:13 AM
True, but it seems in order for life to survive, at least on earth, through mass extinction a species can only take two routes intelligence (humans) or mass reproduction (bacteria). Therefore assuming that extraterrestrial species are forced to endure the same catastrophes as earth, they would have to take 1 of these 2 routes.

Earth has had several mass extinctions. There is no evidence that intelligence followed from any but the latest.

IsaacKuo
2012-Dec-26, 07:06 PM
The useful output is advice to the SETI people on where they should point their radio telescopes and the operational definition of intelligence is something like "can produce detectable modulated radio signals distinguishable from noise and natural (inorganic) processes".

That largely rules out life on panthalassic worlds, life under thick ice sheets,
Why? Even if we assume the dubious theory that advanced technology is impossible without fire, it's possible to burn fires on floating platforms. Note that thick ice sheets will collect pockets of gas in the upside-down equivalent of lakes.

Frank Merton
2012-Dec-27, 11:53 AM
Why? Even if we assume the dubious theory that advanced technology is impossible without fire, it's possible to burn fires on floating platforms. Note that thick ice sheets will collect pockets of gas in the upside-down equivalent of lakes.I fear you are rationalizing out of wishful thinking. Face it, such worlds producing space-traveling technology is unlikely.

Cougar
2012-Dec-27, 01:15 PM
But the galaxy is so freaking big, with so many stars....

Well, let's do the numbers. As of 2012, the Kepler (http://en.wikipedia.org/wiki/Kepler_%28spacecraft%29) mission has identified 2,321 candidate exoplanets. Of these, 207 are similar in size to Earth... Moreover, 48 planet candidates were found in the habitable zones of surveyed stars. The Kepler team estimated that 5.4% of all stars host Earth-size planet candidates, and that 17% of all stars have multiple planets. In December 2011, two of the Earth-sized candidates, Kepler-20e and Kepler-20f were confirmed as planets orbiting a Sun-like star, Kepler-20. - Wiki

ravens_cry
2012-Dec-27, 02:01 PM
Given that you could come to almost any point in Earth's history when it had life and not find intelligent life, I would say it seems unlikely that intelligent life would be as common as other kinds.

primummobile
2012-Dec-27, 03:11 PM
Given that you could come to almost any point in Earth's history when it had life and not find intelligent life, I would say it seems unlikely that intelligent life would be as common as other kinds.


In addition to that, once one form of truly intelligent life emerges it makes it more difficult for other kinds of intelligent life to emerge

IsaacKuo
2012-Dec-27, 04:41 PM
Given that you could come to almost any point in Earth's history when it had life and not find intelligent life,
So far, that is. Even without active human intervention, Earth will remain habitable for billions of years, and during that time there may be intelligent life on Earth. If we stick around, though, we may do things to actively keep Earth habitable for trillions of years to come.

There's also the question of space colonization. It's plausible that non-intelligent life may not be able to propogate throughout space, but intelligent life can. So, the vast majority of worlds with life would have intelligent life.

IsaacKuo
2012-Dec-27, 04:45 PM
I fear you are rationalizing out of wishful thinking. Face it, such worlds producing space-traveling technology is unlikely.
Umm...you don't present the slightest shred of justification for your assertion. Why not? Can you present even the vaguest idea why not?

I know some popular ideas, but they fail to make any sense. For example, there's the popular idea that dolphins can't become technological despite intelligence because they don't have hands. Okay sure...but so what? Plenty of marine animals do, such as squids and crabs and sea otters...

Frank Merton
2012-Dec-27, 05:00 PM
Umm...you don't present the slightest shred of justification for your assertion. Why not? Can you present even the vaguest idea why not?Ah did I hit a sensitive spot? Your reaction seems excessive, when just common sense is all I need. I didn't say impossible, I said improbable.

IsaacKuo
2012-Dec-27, 05:05 PM
Ah did I hit a sensitive spot? Your reaction seems excessive, when just common sense is all I need. I didn't say impossible, I said improbable.
Again, you don't present even the slightest justification for your assertion. Did I hit a sensitive spot? Do you really have nothing upon which to base your apparently baseless belief?

Frank Merton
2012-Dec-27, 05:22 PM
Again, you don't present even the slightest justification for your assertion. Did I hit a sensitive spot? Do you really have nothing upon which to base your apparently baseless belief?First, I have opinions, not beliefs. Beliefs are for church. Second, it is easy to call something "baseless," but obviously I see it otherwise. My reaction to your position, in fact, is that it makes no sense, and, as I already said, seems based on wishful thinking.

IsaacKuo
2012-Dec-27, 05:43 PM
First, I have opinions, not beliefs. Beliefs are for church. Second, it is easy to call something "baseless," but obviously I see it otherwise. My reaction to your position, in fact, is that it makes no sense, and, as I already said, seems based on wishful thinking.
I call your belief apparently baseless, because you have failed to present any base for it, despite repeated requests and opportunities to do so.

Unlike you, I have presented arguments in support of my position. For example, I pointed out that it's possible to burn a fire on a floating platform. This isn't based on wishful thinking. It's an observation of something that is physically possible and demonstrated in reality. We humans burn fires on floating platforms every day.

Another example--I justify my belief that oceanic life forms can have "hands" by pointing out examples of actual oceanic life forms with them. Again--not wishful thinking. Observation of reality.

So...again, could you state any basis to support your assertion?

ravens_cry
2012-Dec-27, 05:45 PM
So far, that is. Even without active human intervention, Earth will remain habitable for billions of years, and during that time there may be intelligent life on Earth. If we stick around, though, we may do things to actively keep Earth habitable for trillions of years to come.

Seems a tad presumptuous to assume we are going to be around that long. Sure, I hope, I hope dearly, but very few species have lasted even close to that long.


There's also the question of space colonization. It's plausible that non-intelligent life may not be able to propogate throughout space, but intelligent life can. So, the vast majority of worlds with life would have intelligent life.
And that has a sample size of zero and is, sadly, speculation as of yet whether it is possible though, again, I hope dearly it is so. If it is possible, we run headlong into the Fermi paradox.

Frank Merton
2012-Dec-27, 05:54 PM
I call your belief apparently baseless, because you have failed to present any base for it, despite repeated requests and opportunities to do so.That sort of statement is just not needed. We disagree. The fact is you think you have presented an argument, because I guess it persuades you. I don't need to present an argument as you have the burden of proof.

I sometimes wonder what our history would be like if we had an atmosphere like that of Venus that didn't allow starlight through, although of course not as deadly. Would we have had a Copernicus, let alone a Brahe or Galileo or Newton?

IsaacKuo
2012-Dec-27, 05:59 PM
Seems a tad presumptuous to assume we are going to be around that long. Sure, I hope, I hope dearly, but very few species have lasted even close to that long.
I did say "if we stick around...". But I don't think "we" need to be a specific species. Does it really matter if "we" continue to evolve into new species, so long as our descendants continue to build upon the knowledge and technology which we have developed? What is it that really matters?

Imagine the converse. Suppose that some homo sapiens culture thousands of years ago developed wonderful amazing technology, but that for some reasons that knowledge was lost. What matters more--that we homo sapiens are the same species as those forsaken ancestors, or that we had to build our technnology and knowledge from scratch?

Note that whether we're talking species continuity or knowledge continuity, it's still an open "if" as to how long "we" will stick around. I'm optimistic, based on how I expect we will survive future disasters, but that's a long and complex line of thought to go through.

And that has a sample size of zero and is, sadly, speculation as of yet whether it is possible though, again, I hope dearly it is so.
I do not base the possibility of space colonization on passive observations of a "sample size". Instead, I base the possiblity on a baseline engineering plan on how to do it. This baseline is excessively conservative--requiring a full 1 gee of artificial gravity, for example, and assuming no advances in medical technology to mitigate radiation effects.

If it is possible, we run headlong into the Fermi paradox.
No, not really. There are so many solutions to the Fermi paradox that it's really not a problem.

Paul Beardsley
2012-Dec-27, 06:00 PM
That sort of statement is just not needed. We disagree. The fact is you think you have presented an argument, because I guess it persuades you. I don't need to present an argument as you have the burden of proof.

Frank, Isaac is offering speculation based on real-world observation, but your response to him is more appropriate to someone making unsupported assertions, which is not what he is doing.

You are under no obligation to give a considered reason for dismissing Isaac's speculation, but your replies would be a lot more interesting if they were a bit more considered.

IsaacKuo
2012-Dec-27, 06:13 PM
That sort of statement is just not needed. We disagree. The fact is you think you have presented an argument, because I guess it persuades you. I don't need to present an argument as you have the burden of proof.
Then your basic failure was a failure to realize that you needed to state your belief that I have the burden of proof.

In fact, the burden of proof is on you. Here is your claim:

"Face it, such worlds producing space-traveling technology is unlikely."

You are the one making a bold claim of probability. I'm merely noting possibility, based on real life examples of what is possible.

I sometimes wonder what our history would be like if we had an atmosphere like that of Venus that didn't allow starlight through, although of course not as deadly. Would we have had a Copernicus, let alone a Brahe or Galileo or Newton?
Copernicus and Brahe? Maybe not. But Galileo or Newton? Sure. Humans were interested in calculating the trajectories of metal balls through the air for practical military reasons. Those reasons would still exist regardless of whether there were interesting things to look at above the sky. The principles of Newtonian physics would have been investigated and discovered.

The history of astronomy would be radically different, because there might be no indication of the greater realm beyond the solar system until the development of radio. After the development of radio, though, the radio telescope would be accidentally invented while trying to measure natural background noise. This is why the Holmdel horn antenna was built. Radio, unlike visible light, penetrates thick clouds. Radio astronomy would then reveal stars and galaxies, as well as detect reflections from meteor plasma trails.

Frank Merton
2012-Dec-28, 08:48 AM
You say, "There are ghosts." I say, "That is unlikely." You say, "No, there are ghosts. I have provided my arguments for their existence, so now you prove they don't exist. I say, "Your arguments are not persuasive, and you have the burden of proof."

Do you see it now?

IsaacKuo
2012-Dec-28, 10:18 AM
You say, "There are ghosts." I say, "That is unlikely." You say, "No, there are ghosts. I have provided my arguments for their existence, so now you prove they don't exist. I say, "Your arguments are not persuasive, and you have the burden of proof."

Do you see it now?
You are making a false equivalence.

First off, and most importantly, there are no scientific arguments for the existence of ghosts.

Second, I am not claiming existence. I am claiming possibility. That is fundamentally different.

A more appropriate equivalence would be:

You say, "It's possible that an AI could have consciousness" I say, "That is unlikely." You say, "No, it's possible. I have provided my arguments for the possibility, so now you prove it's unlikely. I say, "Your arguments are not persuasive, and you have the burden of proof."

Paul Beardsley
2012-Dec-28, 10:25 AM
You say, "There are ghosts." I say, "That is unlikely." You say, "No, there are ghosts. I have provided my arguments for their existence, so now you prove they don't exist. I say, "Your arguments are not persuasive, and you have the burden of proof."

Do you see it now?

I already saw how you thought your argument was coming across. As Isaac pointed out, your equivalence is false.

Frank Merton
2012-Dec-28, 10:31 AM
People don't want to have to prove the truth of unlikely claims, I guess.

mutleyeng
2012-Dec-29, 02:23 PM
So far, that is. Even without active human intervention, Earth will remain habitable for billions of years, and during that time there may be intelligent life on Earth. If we stick around, though, we may do things to actively keep Earth habitable for trillions of years to come.
.

you are being exceedingly generous
http://biogeosciences-discuss.net/2/1665/2005/bgd-2-1665-2005.pdf

without intervention, the window for intelligent life based on our one sample is very small.
We understand the process of simple to complex life with as much clarity as we do the very start of life.

Paul Wally
2012-Dec-29, 03:08 PM
How do we measure intelligence? As far as I can see intelligence is pervasive throughout most if not all biological systems. I don't see it as something that only and especially emerged in humans. One could say there are various degrees of intelligence, but that will also depend on how we measure and distinguish the various degrees of intelligence to be found in all life lifeforms. Why draw the line with human intelligence? What distinguishes human intelligence from other intelligence? I think that what distinguishes human intelligence is it's capacity for rapid cultural evolution, but who's to say other existing species on this planet do not have the biological capacity for cultural evolution too. Perhaps we should define the kind of intelligence of relevance here as the biological capacity for cultural evolution, i.e. non-genetic learning.

IsaacKuo
2012-Dec-29, 03:37 PM
you are being exceedingly generous
http://biogeosciences-discuss.net/2/1665/2005/bgd-2-1665-2005.pdf

without intervention, the window for intelligent life based on our one sample is very small.
We understand the process of simple to complex life with as much clarity as we do the very start of life.
Thank you for that reference. I was only familiar with the earlier results based on stellar evolution and the astrophysical definition of habitable (which predicts Earth will remain in the habitable zone for about 3.5 billion years). I was not familiar with carbon cycle models, which aren't part of astronomy's definition of habitable zone (not yet, anyway).

Intuitively, it seems amazing to me that Earth could naturally run out of carbon, but I'm not familiar with geology.

That specific problem seems straightforward for humans to solve, given the time scales, if we stick around long enough to do it. There is a stupendous amount of carbon dioxide available in Venus. The energy requirements for atmosphere grazing satellites to scoop up CO2, cool it into dry ice, and then sling dry ice blocks toward Earth are not so great, and solar power is powerful in Venus orbit. (There's no need for either disposable or reusable spacecraft. The aiming requirements to hit the huge target of Earth are not too difficult, and no reentry heat shield is necessary.)

Sardonicone
2012-Dec-30, 12:11 AM
Thank you for that reference. I was only familiar with the earlier results based on stellar evolution and the astrophysical definition of habitable (which predicts Earth will remain in the habitable zone for about 3.5 billion years). I was not familiar with carbon cycle models, which aren't part of astronomy's definition of habitable zone (not yet, anyway).

Intuitively, it seems amazing to me that Earth could naturally run out of carbon, but I'm not familiar with geology.

That specific problem seems straightforward for humans to solve, given the time scales, if we stick around long enough to do it. There is a stupendous amount of carbon dioxide available in Venus. The energy requirements for atmosphere grazing satellites to scoop up CO2, cool it into dry ice, and then sling dry ice blocks toward Earth are not so great, and solar power is powerful in Venus orbit. (There's no need for either disposable or reusable spacecraft. The aiming requirements to hit the huge target of Earth are not too difficult, and no reentry heat shield is necessary.)

Even without taking carbon into it, isn't the with the sun burning progressively hotter (and brighter) to the factor of ~10% every billion years, wouldn't it be too hot in a billion years on Earth to support current life? It was my understanding that at those temperatures the increased evaporation rates of the oceans would forever disrupt our current hydrological cycle until we would eventually lead to a run-away greenhouse effect and we'd wind up like second Venus. I could be wrong, but I had thought this was the prevailing theory.

JC Wombopener
2012-Dec-30, 10:37 AM
Hey, new to the forum

I heard one scientist say that the Big Bang resulted in the Universe beginning in what he considered to be it's current state as a infinite body of space. Then I read another describe the Big Bang resulting in a finite body of space which is perpetually expanding.

Any suggestions?

KABOOM
2012-Dec-30, 02:38 PM
Even without taking carbon into it, isn't the with the sun burning progressively hotter (and brighter) to the factor of ~10% every billion years, wouldn't it be too hot in a billion years on Earth to support current life? It was my understanding that at those temperatures the increased evaporation rates of the oceans would forever disrupt our current hydrological cycle until we would eventually lead to a run-away greenhouse effect and we'd wind up like second Venus. I could be wrong, but I had thought this was the prevailing theory.

Yes, I have read that within 500M to 1B years the sun will enter its red giant phase and that the Earth will become a "barren rock" devoid of its oceans.

mutleyeng
2012-Dec-30, 04:26 PM
Yes, I have read that within 500M to 1B years the sun will enter its red giant phase and that the Earth will become a "barren rock" devoid of its oceans.

no its still in its main sequence (for another 5 billion years or so), so its not the red giant phase.
Its illuminancy is increasing while in its main sequence though, so the 500 to 1 ga timescale that complex life has left is still true - but perfectly solvable to a space faring species, so nothing to worry about

IsaacKuo
2012-Dec-31, 03:49 PM
Hey, new to the forum

I heard one scientist say that the Big Bang resulted in the Universe beginning in what he considered to be it's current state as a infinite body of space. Then I read another describe the Big Bang resulting in a finite body of space which is perpetually expanding.

Any suggestions?
It is unknown whether the universe is infinite in spacial extent or merely mind bogglingly big. There's a limit to the radius we can see, due to the speed of light. But as far as we can see, the universe looks like it may be infinite in size. If so, then it has been infinite in size since the start--it's just that everything was much closer to each other then. But if not, then the size of the universe was always finite, with the overall size starting off small and then expanding.

Basically, we don't know which of these is the case. Our observations are consistent with either theory.

Sardonicone
2013-Jan-01, 09:46 PM
no its still in its main sequence (for another 5 billion years or so), so its not the red giant phase.
Its illuminancy is increasing while in its main sequence though, so the 500 to 1 ga timescale that complex life has left is still true - but perfectly solvable to a space faring species, so nothing to worry about

Thanks, forgot to get back to this thread. right on all accounts.

neilzero
2013-Jan-02, 02:43 AM
The Sun is at least 10% hotter than it was 4 billion years ago. but the Earth is possibly cooler. Does that not suggest some sort of temperature regulating mechanism that may give us only slightly warmer when the Sun's output increases another 10%. Apparently, the average radius of Earth's orbit is increasing, but not presently fast enough to cool Earth significantly.
10% hotter sun means about 30 degrees K hotter in the warmer parts of Earth, unless it is square law, then about 5.5 degrees k hotter, which would be tolerable except in most tropical low lands. Neil

whimsyfree
2013-Jan-02, 03:17 AM
Why? Even if we assume the dubious theory that advanced technology is impossible without fire,


You can assume what you like, but I made no such imputation.


it's possible to burn fires on floating platforms. Note that thick ice sheets will collect pockets of gas in the upside-down equivalent of lakes.

So what is your suggestion? that the SETI people should be looking for signal fires on ice sheets?

IsaacKuo
2013-Jan-02, 02:57 PM
You can assume what you like, but I made no such imputation.
I offered such theories as examples of theories which suppose aquatic aliens can't develop advanced technology. As far as I know, none of these theories really make sense.

If you think aquatic aliens can't develop advanced technology, please feel free to chime in on a reason why not.

So what is your suggestion? that the SETI people should be looking for signal fires on ice sheets?
Huh? SETI people look for radio signals. Hypothetical aquatic aliens could send radio signals. We send radio signals from floating platforms (ships) all the time, as well as from platforms on top of ice sheets (polar bases).

SETI is not set up to look for all forms of alien life, just ones with advanced technology and the inclination to send out radio signal greetings our way.

IsaacKuo
2013-Jan-02, 03:11 PM
How do we measure intelligence? As far as I can see intelligence is pervasive throughout most if not all biological systems. I don't see it as something that only and especially emerged in humans. One could say there are various degrees of intelligence, but that will also depend on how we measure and distinguish the various degrees of intelligence to be found in all life lifeforms. Why draw the line with human intelligence? What distinguishes human intelligence from other intelligence? I think that what distinguishes human intelligence is it's capacity for rapid cultural evolution, but who's to say other existing species on this planet do not have the biological capacity for cultural evolution too. Perhaps we should define the kind of intelligence of relevance here as the biological capacity for cultural evolution, i.e. non-genetic learning.
I agree that we should define what kind of intelligence is of relevance here, but I disagree that cultural evolution is the relevant factor here. The issues we're discussing have to do with "advanced technology". This requires some definition also, but I think we can start with a practical definition of certain "advanced" capabilities. These would include:

1) Radio communications. This capability is relevant to SETI and the Drake equation.
2) Space travel. This capability is relevant to Dyson sphere searches, potential lifespan of a "civilization"
3) Self-replicating machine technology (implicitly also including slow interstellar capability). This capability is relevant to Dyson sphere searches, potential lifespan of a "civilization", and the Fermi paradox.
4) Fast interstellar capability. This is also relevant to Dyson sphere searches, potential lifespan of a "civilization", and the Fermi paradox.

It's not necessarily that these are the most "valid" definitions of advanced technology or intelligence, but they're practical definitions useful for studying certain theories about hypothetical aliens, and how to search for them.

Hlafordlaes
2013-Jan-02, 10:51 PM
How do we measure intelligence? As far as I can see intelligence is pervasive throughout most if not all biological systems. I don't see it as something that only and especially emerged in humans. One could say there are various degrees of intelligence, but that will also depend on how we measure and distinguish the various degrees of intelligence to be found in all life lifeforms. Why draw the line with human intelligence? What distinguishes human intelligence from other intelligence? I think that what distinguishes human intelligence is it's capacity for rapid cultural evolution, but who's to say other existing species on this planet do not have the biological capacity for cultural evolution too. Perhaps we should define the kind of intelligence of relevance here as the biological capacity for cultural evolution, i.e. non-genetic learning.

Indeed. I can recall examples of cultural evolution in both chimps (types of tool use varies among groups and is generationally stable via learning by copying) and orcas (pod hunting strategies differ and can include innovations that are adopted by others in the pod, such as how to access a shallow pool where prey is normally safe.) I believe some bird species also display group song differences.

I think our species is now undergoing its own cultural evolution entailing recognition that what we have easily dismissed as mere "instinct" and "conditioned response" is really a lot more complex, and represents a difference from us in terms of degree, not fundamental nature.


I agree that we should define what kind of intelligence is of relevance here, but I disagree that cultural evolution is the relevant factor here. The issues we're discussing have to do with "advanced technology".

I understand cultural evolution to be precisely the necessary condition, but perhaps we are working from different definitions. At any rate, I agree it is the ability to create advanced tools (and do maths) that count.

Marken08
2013-Jan-09, 02:18 AM
Intelligent life is most likely not common in the universe. It is likely that a very specific series of requirments must be met for an extended period of time in order for intelligent life to evolve. I am almost positive that it exists elsewhere, I just don't think that it's common.

transreality
2013-Jan-09, 10:20 PM
Intelligent life is most likely not common in the universe. It is likely that a very specific series of requirments must be met for an extended period of time in order for intelligent life to evolve. I am almost positive that it exists elsewhere, I just don't think that it's common.

some numbers; life has been on earth 3.4 billion years, multicellular life 500 million years, intelligent species (since genus Homo) for 2 million years. That means that at a maximum local estimate, the frequency of intelligence among multicellular life is 0.4%, among life 5.88e-5%.

from earlier numbers, if 5.4% of stars have earth mass planets, lets estimate one in a hundred of these undergo abiogenesis, that makes a billion earths in the milky way. That means on order of 5000-10,000 worlds with intelligent species in the galaxy. I guess it is possible to estimate a density and average separation from that. Analysis, about as valid as the Drake equation..