I think the whole question of "is there intelligent life on other planets and, if so, why haven't they visited us?" is fascinating.
I am, of course, assuming that they haven't visited us, at least not in the recent past, and that the whole "anal probes", "area 51" etc. nonsense is about as credible as pixies at the bottom of the garden.

So, as a starting point, lets just accept that there are millions of "earth-like" (using pretty wide parameters) in our galaxy and the majority of them have recognisable 'life". So, where are they? Why hasn't the SETI program come up with anything either?

I think the SETI question is pretty easy to answer. After all, we have only been using electro-magnetic waves as a form of communication for around 100 years, and that form of communication wasn't even imagined a hundred years before that. Why assume that we will still be using that technology in another 100 years time, especially when the possibilities for other approaches seem pretty open. If that's the case then there could well be millions of civilisations out there who would no more be looking for radio signals than we would be looking for tom tom rhythms.

The other assumption I'd want to question is the whole notion that the evolution of life somehow leads, in an almost inevitable way, to species with our form of intelligence. In other words, its simply a hang-over from the common 19th century anthropocentric vanity that humans are the "pinnacle" of evolution - that evolution leads to us.

But evolution doesn't work that way. It has no ultimate aim (that's just a teleological fallacy). The "tree" of evolution isn't a symmetrical conifer with an angel on top, its a ragged and tattered shrub, and we are a minor twig on an insignificant branch. In comparison to animals like antelopes our evolutionary branch is pretty damn spindly. In fact, the DNA evidence seems to indicate that we came VERY close to extinction. There may, at one stage, have been as few as a couple of thousand of the ancestral hominids that were the ancestors of all of us.

Which leads to a further consideration. It may well be that "intelligence" as we conceive of it may not be a particular good survival trait, at least in the very early stages of technological development. Our "crowning glory" may turn out to be little more a lucky consequence of a particular set of environmental conditions. After all the dinosaurs were at least as "evolved" as we are, and they were around for over 130 million years and yet, as far as we know, none of them ever developed a technological civilisation.

I think there's a lot more to be said on this topic if anyone else is interested.

Not from me as I'm about as interested in the topic as I am in the existence of god(s).
Sorry.
BTW, we had leg of lamb from Oz a couple of days ago. Quite tasty and tender, too.

You do realise that was "alien lamb" doncha?

I'm more interested in finding intelligent life here on Earth.

Australia is part of an alien experiment.

Ahhhhh. But is it working Macro?

I think the reason we haven't detected signals from other worlds is because within 2 centuries of discovering the atomic bomb, civilizations destroy themselves.

Ha.......good post

All of them SciFi?
That would be an incredible long shot.

Besides, you don't need an understanding or knowledge of atomic bombs to have sophisticated communications technology.

Technological development isn't a predetermined process anymore than evolution is.

Most planets don't have life.

Probably only about 5% of all the planets in the Universe have life. Most of that life will be just plant and animal life.

Probably only 1/10 of 1% of all planets in the Universe have life that has developed technology.

Of those planets, how many have advanced to the point that they have radio technology? And they would have to continue using radio technology for tens of thousands of years. If they only use it for a few hundred years, then the likelihood that we would happen to be listening right during that small window is very slim.

Of course, we sort of already know that they won't be using radio waves to transmit data -- at least not powerful signals like from FM radio and television stations -- since they would have quickly moved on the better technologies, such as close-circuit cable or fiber-optics, or some method we haven't developed yet. So the window where they would be sending powerful signals into space is probably only a century or two. Again, that's a very small window. We'd have to be listening during those two centuries.

Keep in mind, too, that radio waves become weaker and weaker as they move through space, so if those civilizations are very far away, by the time those signal reach Earth they may be too weak to pick out from all the background noise.

Most planets don't have life.
A guess. Can you back it up?

Probably only about 5% of all the planets in the Universe have life. Most of that life will be just plant and animal life. Another guess.

Probably only 1/10 of 1% of all planets in the Universe have life that has developed technology.
A third guess. Besides, if correct, and given that the current estimates are that there are somewhere in the order of 60 billion planets In our Galaxy that gives us 60 million...

Of those planets, how many have advanced to the point that they have radio technology? And they would have to continue using radio technology for tens of thousands of years. If they only use it for a few hundred years, then the likelihood that we would happen to be listening right during that small window is very slim.

Of course, we sort of already know that they won't be using radio waves to transmit data -- at least not powerful signals like from FM radio and television stations -- since they would have quickly moved on the better technologies, such as close-circuit cable or fiber-optics, or some method we haven't developed yet. So the window where they would be sending powerful signals into space is probably only a century or two. Again, that's a very small window. We'd have to be listening during those two centuries.While I admit that its rather flattering for you to simply paraphrase what I already said in paragraph 3 of the opening post, it is a little bit redundant don't you think?

Keep in mind, too, that radio waves become weaker and weaker as they move through space, so if those civilizations are very far away, by the time those signal reach Earth they may be too weak to pick out from all the background noise. The SETI guys are already well aware of that and there are some incredibly sensitive receivers available. I don't think that's a huge problem.

I don't have a deep science background but I see it as astoundingly arrogant to believe we are the only "intelligent life" ~ I don't think we even know how many other galaxies exist in "the universe" ~

Sooz

The "It's a big galaxy, Mr. Scott" Scenario
We're talking several light-years, so even if they had something comparable to 'warp drive' they would have a lot of exploring to do.

The "Let's call the whole thing off" scenario
Just because we are a curious species doesn't mean other intelligent life is too. They may be completely different in terms of their wants, needs, goals, etc.

The "overinflated human ego" scenario
They may not be interested. Discovering we exist may be of no more importance to them than if you found an ant colony in your yard.

The Prime Directive scenario
They may prefer to watch us than interact with us knowing that any interaction may change our behavior and alter our society.

The "Where's the beef?" scenario
It may be arrogant to think we are special, but we have yet to find evidence to suggest that life developed beyond the Earth. Which means it's still possible there is nothing out there, no matter how likely we think it should be.

The "stumbling in the dark" scenario
How we perceive our Universe may be so limited or even inaccurate that it's akin to a blind man deep within a cave wondering who tuned out the lights. Pondering extraterrestrial life may not even be a valid question.

Sci-Fi: Probably only about 5% of all the planets in the Universe have life. Most of that life will be just plant and animal life.

Maybe my old brain isn't working today but doesn't the earth only have plant and animal life?

I will not judge the rest of the universe by what we have here. Our technology here could be extremely primitive compared to other places. Maybe other places have not even bothered wth radio waves and such. Maybe there are other things that are far better that we will never know.

You know, it is possible that others have explored here and found us not worth their time. They will just let us superior humans destroy the environment and ourselves and see what happens next time.

Some seem to think that all the technology is what makes us great. Personally, I disagree. I would find far superior a place where all work together so that everything can survive. That to me would be real progress.

I think the current estimates are around 100 - 200 billion observable Galaxies in the universe Sooz. Of course, there very well could be many more we either can't observe or couldn't possibly observe. Lets just say that the universe is BIG!

They (the aliens) forgot their towels and had to go back for them.

The "It's a big galaxy, Mr. Scott" Scenario
We're talking several light-years, so even if they had something comparable to 'warp drive' they would have a lot of exploring to do.
Actually we are talking about around 100,000 light years (and that's just the Milky Way).

The "Let's call the whole thing off" scenario
Just because we are a curious species doesn't mean other intelligent life is too. They may be completely different in terms of their wants, needs, goals, etc.
True, but you would expect SOME to be. That's all we need.

The "overinflated human ego" scenario
They may not be interested. Discovering we exist may be of no more importance to them than if you found an ant colony in your yard.
Ditto.

The Prime Directive scenario
They may prefer to watch us than interact with us knowing that any interaction may change our behavior and alter our society.
Possible. But for that to be effective you'd have to have some kind of interstellar accord between different civilisations (like the one described in David Brin's Uplift[i][/i] series.

The "Where's the beef?" scenario
It may be arrogant to think we are special, but we have yet to find evidence to suggest that life developed beyond the Earth. Which means it's still possible there is nothing out there, no matter how likely we think it should be.
Actually, there's plenty of evidence to suggest[u] that life developed beyond the earth. In particular, the existence of organic compounds, including amino acids -the building blocks of DNA - in interstellar space has been pretty well confirmed.
And the other point is, considering just how BIG, BIG, BIG (ad as many "BIGS" as you like) the universe is the notion that this is the [u]only planet to have developed life would make the Earth so stunningly unique that the likelihood is in the order zillions upon zillions to one.

The "stumbling in the dark" scenario
How we perceive our Universe may be so limited or even inaccurate that it's akin to a blind man deep within a cave wondering who tuned out the lights. Pondering extraterrestrial life may not even be a valid question.
True enough. But we can only work with what we have. Otherwise there's no point in talking about anything.

I find this an interesting issue. If you don't that's fair enough, but I don't see any reason to mock it.

A few of the responses seem to be based on the "only one lot of aliens" premise. But, If there's one there's likely to be lots ...

I think we're reading John's post differently, CM ~ I don't see it as "mocking" ~ I read it as identifying how various mindsets [especially those mindsets withOUT a deep science knowledge base] approach the question ~

Sooz

Sooz, I don't think CM was talkiing about John wth the "mocking". He deliberately put that in a separate post. I think if he had thought John was mocking, he wouldn't have taken so much time to respond to his post. I may be wrong, of course.

I'm not sure if you're referring to my comments, but if you are then Sooz is right - I'm not mocking anything and also find this an interesting topic. (If Jeanne is right then it would good to know who it is that you think was mocking the topic.)

I just thought I'd point out what I believe to be various possibilities. Perhaps my method made it seem that I wasn't serious, but actually I was.

And I agree with your replies in #17, Cattleman. There are many possibilities but as new discoveries are made we can narrow them down.

It certainly wasn't John.
But posting old and tired one-liners is a kind of "mocking" in my book.

Pardon me for having a bit of fun with this topic. Like Sooz said, there are "those mindsets withOUT a deep science knowledge base" so we hear things such as "ancient aliens" and it all gets a bit silly.

I'm not sure why you see it as mocking. I think I raised some valid points.

As I said, it wasn't your comments at all John. I thought they were valid points and I responded to them as such.