Existance of extraterestrial form of life

[Akshay_Anti]

Do you believe in existence of extra-terrestrial beings? why/Why not?

 

[micromass]

Do you believe in existence of extra-terrestrial beings? why/Why not?

Yes, I believe that extra-terrestrial beings exist.

I do not have evidence for this fact, so I acknowledge that I can be wrong, however, the chances that they exist seem pretty large to me.
I do not believe extra-terrestrial beings visited earth. That just seems silly.

 

[Akshay_Anti]

I do not believe extra-terrestrial beings visited earth. That just seems silly.

Why so?

 

[micromass]

Why so?

Other people can explain it better than me:

https://www.youtube.com/watch?v=EYPapE-3FRw

https://www.youtube.com/watch?v=9BRDCxNEuyg

 

[Charmar]

Yes.

Why, because of probability, even though the following is a quote and webcomic, the combination between the two of them accurately depicts my opinion.

Space is big. Really big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space. -Douglas Adams
Also: xkcd.com/1123/ All you need is H and time.

As for why we haven’t heard from good old ET take a look at http://en.wikipedia.org/wiki/Drake_equation

 

[OmCheeto]

Didn't Clinton claim that Martians once visited the earth? Whatever happened to that?

 

[EBENEZR]

I've heard people say that probability states that likelihood is high, but how is this worked out?

From what I can tell of extraterrestrial life probability, we can't judge how common it is when the only point of reference we have is ourselves. Currently we're trying to judge how many things are in a room with no lights and without a torch. Are we the only things in the room? We'll only find out when we find it.

 

[f95toli]

I've heard people say that probability states that likelihood is high, but how is this worked out?
.

Did you follow the link above to the wiki on Drake's equation?
There are of course a number of unknowns in that equaion, but we are getting better data. We e.g. now that that there are planets in a very large proportion of solar systems, and there was no data at all about this when Drake first wrote down his equation.

 

[EBENEZR]

Did you follow the link above to the wiki on Drake's equation?
There are of course a number of unknowns in that equation, but we are getting better data. We e.g. now that that there are planets in a very large proportion of solar systems, and there was no data at all about this when Drake first wrote down his equation.

Yes I did and I find it insufficient to suggest that we are entitled to state likelihood is anything but pitiful no matter how much we want to think life out there is likely - this is wishful thinking, not science.

n_e
How many have we found that can support life? How do we know it can support life with any degree of certainty? Surely any planet is capable of supporting life until we know what all life of all varieties is and isn't capable of surviving. We only have an idea of the upper and lower limits on Earth and even then we often find a new record breaking living organisms.

f_ℓ
So far, we only know of one, Earth, out of hundreds of planets. Drake's Equation goes on to civilisations... we're still stuck at "well, we haven't found anything microbial yet." in which case, probability is looking pretty low.

EDIT: Sorry I guess I wasn't clear. What I meant by "how is this worked out?" was "how can people come to such an optimistic conclusion?"

 

[Jimmy Snyder]

Did you follow the link above to the wiki on Drake's equation?
There are of course a number of unknowns in that equaion, but we are getting better data. We e.g. now that that there are planets in a very large proportion of solar systems, and there was no data at all about this when Drake first wrote down his equation.

The problem with this argument is that if even one of the factors in Drake's equation is unknown, then the entire equation fails. I don't mean to say that the equation is entirely useless, only that it fails to predict whether or not we are alone. Here are the factors.

R = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

 

[Ryan_m_b]

Whilst space is big and old and we know that life is possible we have no real idea of how likely it is. Earth could be a one in one google chance, or it could be far lower. At the moment we don't know.

Without a comprehensive theory of abiogenesis we're in the dark on this one.

 

[Jack21222]

Didn't Clinton claim that Martians once visited the earth? Whatever happened to that?

He was referring to the Allan Hills 84001 meteorite. http://en.wikipedia.org/wiki/Allan_Hills_84001

 

[f95toli]

The problem with this argument is that if even one of the factors in Drake's equation is unknown, then the entire equation fails. I don't mean to say that the equation is entirely useless, only that it fails to predict whether or not we are alone. Here are the factors.

R = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space

I agree. But the point I was making was that we at least know more now than we did 50 years ago. We a getting close to having good estimates for R, fp and if we limit ourselves to life "as we know it" we could presumably also estimate ne (planets with liquid water etc). I suspect most astrobiologists would agree that fl is a farily large number. What is missing is good estimates for fl and fc (we can use ourselves as an example to put a lower bound for L, let's say at least 100 years).

Even fairly pessimistic estimates tend to put he number of detectable civilizations in our galaxy to be larger than 1.

Also, the question was extraterestial LIFE -not neccesarily intelligent- in which case the last four factors disapear. This means that the only uncertainty is fl; which -as mentioned above- should be prettly large.

 

[EBENEZR]

I agree. But the point I was making was that we at least know more now than we did 50 years ago.

But knowing about planets doesn't really count for anything. If we walk past a house in the street, we can say with a good level of probability someone lives in it, because it was purposely built to have someone live in it. Planets on the other hand, it doesn't matter how inhabitable they are, they could be what we would call a paradise, but if they don't have any life on them then it's all pretty futile, right? Why is "knowledge of average pre-discovery life" (ie life we know exists at the moment) not get factored in? You could count a million planets are that inhabitable, but if only one has provable life on it, surely each new inhabitable but lifeless planet decreases the likelihood?

We a getting close to having good estimates for R, fp and if we limit ourselves to life "as we know it" we could presumably also estimate ne (planets with liquid water etc). I suspect most astrobiologists would agree that fl is a fairly large number. What is missing is good estimates for fl and fc (we can use ourselves as an example to put a lower bound for L, let's say at least 100 years).

How many of the planets that we have found, have been super-Earths, earth-like, hot jupiters or Earth's so close to their parent star they're screwed?

Even fairly pessimistic estimates tend to put he number of detectable civilizations in our galaxy to be larger than 1.

"tend to"? I'm assuming that every estimate has to be larger than one, due to the amount of civilisations on Earth.

Also, the question was extraterestial LIFE -not neccesarily intelligent- in which case the last four factors disapear. This means that the only uncertainty is fl; which -as mentioned above- should be prettly large.

I agree, I wouldn't bother with above f_ℓ for the time being, I think achieving this will be a mountainous task.

I think it would be very interesting (understatement of 2012) to find life off of Earth and I want there to be something. I think a lonely existence in the universe would be a bit of a downer (runner up understatement of 2012). However, we have not found anything that comes really close to Earth yet, have we? An interesting perspective is the idea of the seed. There must be life out there because where did our life come from if abiogenesis turns out to be unfeasible? (even if it happened on Earth, doesn't mean it will happen elsewhere). We could turn this on its head - maybe we are the seeding life for the universe?

Sorry if I come across as aggressive or argumentative in this post, f95toli, it's not my intention, I was just trying to be clear cut with my criticism. If I'm entirely wrong on the premises of my points then I'll be happy to concede.

 

[phinds]

Yes, I believe that extra-terrestrial beings exist.

I do not have evidence for this fact, so I acknowledge that I can be wrong, however, the chances that they exist seem pretty large to me.
I do not believe extra-terrestrial beings visited earth. That just seems silly.

My thoughts exactly !

 

[trueo]

true, they exist and they may be looking for extra-terrestrial beings too.

 

[Andre]

Anyway, I wonder if ET speculation is science, as in using the scientific method (Mm's Feynman lecture). Here is the hypothesis: intelligent ET exists/does not exist. Compute - Drake's equation; compare to nature, now what? Fail or are we too impatient and should we listen another million years?

Also why is Venus not much more like Earth while it's close to the Goldilocks zone?

 

[Jimmy Snyder]

fℓ is rather a large problem is it not? If N is the number of candidate planets in the universe, that is, planets that could support life, then this is what we have discovered so far.

\frac{1}{N} \le fℓ \le 1

In other words, we haven't learned anything we didn't know when we were living in caves. As I said, if you don't know even one of the factors of Drake's equation, then it provides no answer to the question at hand.

 

[phinds]

true, they exist and they may be looking for extra-terrestrial beings too.

You should read the forum rules. Definitive statements of fact have to be ones that can be backed up by citations. CLEARLY this statement cannot be validated.

 

[arildno]

I feel there is life out there, but have no valid arguments for my position.

 

[phinds]

I feel there is life out there, but have no valid arguments for my position.

Yep, me too. It just seems SO unlikely that with all the stars/planets in just the OBSERVABLE universe the odds of Earth being the only time life formed are infinitesimal. But like you, I have no facts to back that up.

 

[arildno]

The problem with this feeling of unlikelihood is, of course, that IF the conditions of intelligent life are so stringent that only one planet in the entire universe can be expected to have them, we by necessity live on that exceptional planet, even though the weird conditions seem perfectly normal to us.

It is our feeling of the normality of our living conditions (in lieu of actual knowledge of the distribution of critical condition) that tempts us into thinking life must exist elsewhere, too.

 

[Jack21222]

The problem with this feeling of unlikelihood is, of course, that IF the conditions of intelligent life are so stringent that only one planet in the entire universe can be expected to have them, we by necessity live on that exceptional planet, even though the weird conditions seem perfectly normal to us.

It is our feeling of the normality of our living conditions (in lieu of actual knowledge of the distribution of critical condition) that tempts us into thinking life must exist elsewhere, too.

The conditions for life don't seem terribly stringent. All you need are some very common chemical ingredients, a medium for those ingredients to interact, and an energy source.

Now, intelligent life might be a completely different topic. It took billions of years for intelligence to evolve on Earth, but life developed very quickly.

 

[Drakkith]

The conditions for life don't seem terribly stringent. All you need are some very common chemical ingredients, a medium for those ingredients to interact, and an energy source.

Now, intelligent life might be a completely different topic. It took billions of years for intelligence to evolve on Earth, but life developed very quickly.

We don't know what the conditions responsible for creating life are. We have several ideas, but none have gone all the way yet. I understand that the basic ingredients for life are found in many places, but the conditions that gave rise to life simply aren't known yet. (Or if we do happen to know them, we haven't been able to show that we know)

 

[Ryan_m_b]

The conditions for life don't seem terribly stringent. All you need are some very common chemical ingredients, a medium for those ingredients to interact, and an energy source.

Now, intelligent life might be a completely different topic. It took billions of years for intelligence to evolve on Earth, but life developed very quickly.

Current hypotheses and research into abiogenesis are already far more complex than presented here and without a comprehensive theory of abiogenesis it's not possible to say at this point exactly what the conditions are. It could turn out that it is extremely common to find RNA, PAH and/or iron-sulphur worlds but that cellular life is incredibly rare to non-existent. Or it could be as you say and that macroscopic life is very common but organisms as "intelligent" as us are incredibly rare to non-existent (I use quotes because IMO it's too ill-defined a word to be of much use here and can lead us in wrong directions).

By the way whether or not life developed very quickly on Earth depends entirely on where you're drawing the line on what life is. If you class micelle structures containing autocatalytic RNA as life then you're going to have a date for life on Earth as far earlier than if you drew the line closer to archaea.

 

[Mentalist]

I have always believed in the existence of life on other planets. The reason is attributed to the vastness of the universe.

 

[Jack21222]

By the way whether or not life developed very quickly on Earth depends entirely on where you're drawing the line on what life is. If you class micelle structures containing autocatalytic RNA as life then you're going to have a date for life on Earth as far earlier than if you drew the line closer to archaea.

Prokaryotes developed about 1b years after the Earth was formed. I'd say that is very quick considering the age of the Earth, and the fact that the Earth was basically molten for much of that first 1b years.

So no, it doesn't matter entirely on where you draw the line on what life is. Any reasonable definition of life gets you to "very quickly."

 

[Ryan_m_b]

Prokaryotes developed about 1b years after the Earth was formed. I'd say that is very quick considering the age of the Earth, and the fact that the Earth was basically molten for much of that first 1b years.

So no, it doesn't matter entirely on where you draw the line on what life is. Any reasonable definition of life gets you to "very quickly."

That really doesn't change anything I've said. To address this idea of "quickly" a bit further, it's not really appropriate to talk in terms of speed with regards to evolution as it is not a race towards some end goal. Environmental conditions could have been such to favour the evolution of prokaryote-like organisms much earlier (within limits), or much later. Furthermore terms like "quickly" are not only subjective but relative, we may one day find out that one billion years is very slow compared to other planets with life, or the reverse, or neither.

A sample size of one really isn't much to draw any conclusions from.

 

[f95toli]

fℓ is rather a large problem is it not? If N is the number of candidate planets in the universe, that is, planets that could support life, then this is what we have discovered so far.

Possibly. But remember that it doesn't really matter if fl is 0.5 or 1e-5; we know that there there are so many planets it our galaxy (not to mention the univerise) that even if you are off by a few orders of magnitude the result is still that there will be a significant number of planets will life out there.
We've just been looking for a few years and we already know of hundreds of planets and thousands of candidates (look at the Kepler website). Most of the ones we know of are giants, but it DOES tell us that there are plenty of solar systems out there (I believe the current estimate is that 20% of all starts have planets).

And yes, fl could be lower than 1e-5 (or whatever), but we know that it is not zero (since it is happened at least once). Also, as far as we know Earth isn't "special" in any way in terms of the "raw material" that is available for chemical reactions (minerals etc.) since our sun is a pretty "average" star, whatever chemical (and late biological) process took place here could presumably also take place on another planet with similar conditions.

 

[Jimmy Snyder]

Possibly. But remember that it doesn't really matter if fl is 0.5 or 1e-5; we know that there there are so many planets it our galaxy (not to mention the univerise) that even if you are off by a few orders of magnitude the result is still that there will be a significant number of planets will life out there.

It matters a great deal. If it's 1/N, then there is only one planet with life and we are it. In that case what doesn't matter is how large N is.

 

[EBENEZR]

It's impossible to judge the likelihood of life when Earth is the only example we know exists. We may as well be trying to measure the nose of the Emperor of China. Unless we know the absolute limits of life we cannot fathom the likelihood of its presence. That is like guessing how many golf balls are sitting around a course on the basis you have found one by a tree. Any attempts at calculation without perspective is mere speculation. Currently, we have no perspective.

 

[daveb]

Life and intelligent life are two different balls of wax. Life? Probably. Intelligent life (let's for the moment assume we're intelligent, a stretch, I know)? I'd rather first find out that there is life. Then I'll worry about the intelligent ones (until they come to ray-zap me, of course).

 

[Jack21222]

That really doesn't change anything I've said. To address this idea of "quickly" a bit further, it's not really appropriate to talk in terms of speed with regards to evolution as it is not a race towards some end goal. Environmental conditions could have been such to favour the evolution of prokaryote-like organisms much earlier (within limits), or much later. Furthermore terms like "quickly" are not only subjective but relative, we may one day find out that one billion years is very slow compared to other planets with life, or the reverse, or neither.

A sample size of one really isn't much to draw any conclusions from.

This planet will exist for roughly 10 billion years. Life developed in the first 10%. While that's subjective, I feel that most people would agree that that's quick.

A sample size of one is plenty to draw conclusions from. We can conclude that life exists in the universe. Us. There are roughly an Avagadro's number of planets in our universe. To me, it just seems far more likely that the Copernican principle can be extended to this and we're not in some special place in the entire universe where life can develop.

 

[Jimmy Snyder]

To me, it just seems far more likely that the Copernican principle can be extended to this and we're not in some special place in the entire universe where life can develop.

You are using the principle that we are not special to answer the question of whether we are special or not.

 

[Ryan_m_b]

This planet will exist for roughly 10 billion years. Life developed in the first 10%. While that's subjective, I feel that most people would agree that that's quick.

I don't disagree that people may say that but regardless you can't really say if it is actually quick for that type of event without having other examples. Furthermore it's largely not relevant because without understanding all the conditions for abiogenesis and early evolution we can't know how common they are.

A sample size of one is plenty to draw conclusions from. We can conclude that life exists in the universe. Us. There are roughly an Avagadro's number of planets in our universe. To me, it just seems far more likely that the Copernican principle can be extended to this and we're not in some special place in the entire universe where life can develop.

Like Jimmy I'm seeing some circular reasoning here. We're asking the question "how exceptional is the genesis and evolution of life on Earth?" and you're addressing it with "if we assume that we aren't exceptional then it's likely that we aren't exceptional".

 

[EBENEZR]

You are using the principle that we are not special to answer the question of whether we are special or not.

Yes, I don't see how this is a Copernicus-like situation. Copernicus made a hypothesis based on the observations of the movements of planets which conflicted with geocentricism. The idea that geocentricism wasn't true was based on observation, whether or not we are truly special is irrelevant. If we are special and unique, that's the way it is, we haven't currently got any reason to believe otherwise. It is like the teapot in Saturn's rings, I guess it's possible, but it seems like a worryingly religious approach of "I choose to believe it because there is no evidence against there being other life."

Correct me if I'm wrong but I didn't think science was about proving negatives, we'd be in the same place forever otherwise. We can only base theories and hypotheses on what we do know and see and in this case, there is no evidence for life off of Earth. I have no problem with believing there is life elsewhere in the universe, because I believe this myself, but I do think there is a problem with saying that because life exists on Earth, life in any sense (despite lack of evidence, and I understand that our ability to detect life is likely pretty feeble) has anything like a significant probability of existing, let alone saying it must. Such assertions are not very scientific - and that's coming from someone who is unable to give up a belief in God. Based on evidence and evidence alone, we currently cannot assert anything other than we are sure life as we have defined it exists here on Earth. Everywhere else is currently moot.

 

[f95toli]

Like Jimmy I'm seeing some circular reasoning here. We're asking the question "how exceptional is the genesis and evolution of life on Earth?" and you're addressing it with "if we assume that we aren't exceptional then it's likely that we aren't exceptional".

But the difference is that we are starting to have a pretty good idea of what is going on in other solar systems in terms of the number of planets, chemistry (based on the type of star) etc. When Drake first came up with his equation no one even had any idea of how common planets are, now we know that they are pretty common. We've also found quite a few different types (i.e. rocky planets etc).
Hence, so far everything points towards the fact that we live in a pretty "typical" system; which supports with the idea that our spot in the galaxy is not very special.

At the moment we are still dealing if probabilies (with very large error bars). But in a few years time we will hopefully be able to do spectroscopy of planets in other systems, and that will reduce the uncertainty quite a bit.
This area has gone from being pure speculation, to a pretty rigorous are of science.

 

[Ryan_m_b]

But the difference is that we are starting to have a pretty good idea of what is going on in other solar systems in terms of the number of planets, chemistry (based on the type of star) etc. When Drake first came up with his equation no one even had any idea of how common planets are, now we know that they are pretty common. We've also found quite a few different types (i.e. rocky planets etc).
Hence, so far everything points towards the fact that we live in a pretty "typical" system; which supports with the idea that our spot in the galaxy is not very special.

I disagree with your conclusion, whilst we might have a pretty good idea compared to when Drake first came up with his equation it is still not good enough. When you say we have a good idea of chemistry that's being a bit generous but even if we did know that planets with primordial-Earth like chemistry and conditions were common we'd still not know whether or not life was common because we don't have a theory of abiogenesis and so we don't know what the necessary conditions for life are nor the chance that they will give rise to something we'd call life.

It doesn't matter if we start filling in the blanks on the Drake equation it's still can't give us an answer if we don't have a good idea of all the info.

 

[Jimmy Snyder]

But the difference is that we are starting to have a pretty good idea of what is going on in other solar systems in terms of the number of planets

fp = the fraction of those stars that have planets

chemistry (based on the type of star) etc.

ne = the average number of planets that can potentially support life per star that has planets

When Drake first came up with his equation no one even had any idea of how common planets are, now we know that they are pretty common.

fp = the fraction of those stars that have planets

We've also found quite a few different types (i.e. rocky planets etc).

ne = the average number of planets that can potentially support life per star that has planets

Pure speculation:
fℓ = the fraction of the above that actually go on to develop life at some point

If even one of the factors in Drake's equation is unknown, then the entire equation is unknown.

 

[Mentalist]

Why are you being serious Jimmy?

 

[Jimmy Snyder]

Now you are saying that we are not special with regard to being a planetary system, therefore we are not special in regard to anything else either.

 

[Drakkith]

I don't really see the issue here. We have NO idea if life has emerged anywhere else in the universe other than Earth. Period. Until we KNOW that life is possible elsewhere, the drake equation is utterly useless. You can put in "what ifs" and whatever assumptions you want, but in the end it's idle speculation for now.

Now you can BELIEVE that life exists elsewhere without having evidence, as many people here do, but you cannot say with ANY certainty that life does or does not exist elsewhere.

 

[Whovian]

Yes I did and I find it insufficient to suggest that we are entitled to state likelihood is anything but pitiful no matter how much we want to think life out there is likely - this is wishful thinking, not science.

n_e
How many have we found that can support life? How do we know it can support life with any degree of certainty? Surely any planet is capable of supporting life until we know what all life of all varieties is and isn't capable of surviving. We only have an idea of the upper and lower limits on Earth and even then we often find a new record breaking living organisms.

f_ℓ
So far, we only know of one, Earth, out of hundreds of planets. Drake's Equation goes on to civilisations... we're still stuck at "well, we haven't found anything microbial yet." in which case, probability is looking pretty low.

EDIT: Sorry I guess I wasn't clear. What I meant by "how is this worked out?" was "how can people come to such an optimistic conclusion?"

Okay, you're right, it's not actually science. That's why this isn't in one of the "science" fora.

Anyway, the people coming to an optimistic conclusion think along the lines of, "okay, planets with life are probably pretty rare, but them being so rare that Earth is the only one in the observable Universe is just ridiculous." Yes, this is somewhat subject to human though processes.

Anyway, I've always somewhat disliked the Drake Equation. It simply repeatedly states

\dfrac{a}{b}=\dfrac{a}{c}\cdot\dfrac{c}{b}

 

[Andre]

So we agree, no science here.

One more thing, I just want to compare this post with ...

Other people can explain it better than me:

https://www.youtube.com/watch?v=9BRDCxNEuyg

Check at about 4:40

 

[SHISHKABOB]

at the same time that it makes sense to say "well there are SO MANY stars out there, that there's just got to be more with life than ours"

I also have to ask the question that Fermi asked as well: "Where are they?"

these two totally contradicting positions both make sense, but like almost totally contradict each other

so I generally put the idea out of my head because it's one of those questions that doesn't really help me in any way

 

[f95toli]

So we agree, no science here.

Again, it depends on if you are talking about ET visiting us (which is a ridiculous idea) or the possibility of life (of some sort) on other planets. While we can't say anything for sure about the latter it is definately science. There is a reason there is whole discipline called astrobiology.
Moreover, if it was impossible to say anything about the possibility of detecting life Darwin-like space missions would be meaningless. Cleary, there are enough scientist that believe that the probability is somewhat larger than zero for this to be taken seriously.

This is no different than e.g. writing a research proposal where you propose a high-risk project with lots of unknowns, while you can't say anything for sure until the research is actually done you can still use what we DO know to say something about the likelihood of success.

 

[Andre]

Again, it depends on if you are talking about ET visiting us (which is a ridiculous idea) or the possibility of life (of some sort) on other planets. While we can't say anything for sure about the latter it is definately science.

Te reason why I think it's not science is because you can't falsify the idea of ET. If there is no proof now and within the next *fill in any looong era with plenty of zero's* years, you can't say anything.

 

[Drakkith]

Te reason why I think it's not science is because you can't falsify the idea of ET. If there is no proof now and within the next *fill in any looong era with plenty of zero's* years, you can't say anything.

But it IS falsebiable in principle. We can't observe every star in the universe, but the underlying principles are easily able to be studied from here on Earth. The same applies to astrobiology. The physical laws that seem to underpin life are able to be studied and tested. We can verify and falsify these laws.

 

[Andre]

But it IS falsebiable in principle. We can't observe every star in the universe, but the underlying principles are easily able to be studied from here on Earth. The same applies to astrobiology. The physical laws that seem to underpin life are able to be studied and tested. We can verify and falsify these laws.

Whilst chemical and physical processes should be the same everywhere or not, I don't know, it would allow for ET somewhere sometimes. No doubt about that. But that doesn't mean that we have any idea about it's probability. The Drake Equation could easily end up with an error margin of X digits. Think of a BIG X.

Also interestingly, in the evolution on Earth, nature took many many sidesteps before really evolving brain power of the primates. It took many extinctions, erasing the sort of 'dead ends' in evolution. Drake does not account for that.

Also check this discussion, without recycling carbon due to plate tectonics, carbon based life could tend to terminate itself quickly. All extra restrictions on Drakes equation; apart from why Venus is not like Earth.

Essentially, having an Earth is not enough, you'd also need the happy accidents that led to the brain power evolution of the primates.

 

[OmCheeto]

Whilst chemical and physical processes should be the same everywhere or not, I don't know, it would allow for ET somewhere sometimes. No doubt about that. But that doesn't mean that we have any idea about it's probability. The Drake Equation could easily end up with an error margin of X digits. Think of a BIG X.

Also interestingly, in the evolution on Earth, nature took many many sidesteps before really evolving brain power of the primates. It took many extinctions, erasing the sort of 'dead ends' in evolution. Drake does not account for that.

Also check this discussion, without recycling carbon due to plate tectonics, carbon based life could tend to terminate itself quickly. All extra restrictions on Drakes equation; apart from why Venus is not like Earth.

Essentially, having an Earth is not enough, you'd also need the happy accidents that led to the brain power evolution of the primates.

-----------------------------
I told people in chat today that I had a premonition of getting banned tonight.
I would expand on your hypothesis Andre, but then we both might be banned.
ps. how many spare rooms do you have?