The Fermi Paradox

[QED]

In this debate I would like to see some resolutions offered to The Fermi Paradox:

[T]he apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.

The extreme age of the universe and its vast number of stars suggest that if the Earth is typical, extraterrestrial life should be common. Discussing this proposition with colleagues over lunch in 1950, the physicist Enrico Fermi asked: "Where are they?"

Note that when it comes to the colonization of our galaxy it would take only one ETC (extraterrestrial civilization) to pull it off. So offering an explanation such as "they blow themselves up before they embark on a program of colonization" wouldn't be particularly convincing as it would have to be something that got in the way of all ETC's ambitions.

Colonization seems to be a reasonable expectation as life appears to spread wherever resources permit. Various estimates range from around one to ten million years for a wave of colonization to sweep throughout the galaxy -- based on propulsion systems consistent with known physics. Although long in terms of a civilization, this kind of time-scale is nothing in terms of the age of the universe and is within the span of many of our own terrestrial species.

So, given the conservative estimate that conditions in the universe were amenable to life some 3 billion years before us (Livio 1999) we might expect ETC's to have expanded into every conceivable niche, or at least have left evidence of such an expansion behind by now.

Question for debate: Where are they?

[earl]

Hugh DP ,Hello to you.
In view of your usergroups you may have no regard or concern for discovery of "where they are" because things flagged as spiritual subject matter may be 'out of the question'as useful information.
I find this is most likely the case.
I do say the topic is interesting.

[QED]

QED, did you read about the star exploding about 7.5 billion years ago?
It was first seen just a bit ago and they were talking about Gamma rays that travel near the speed of light and I was wondering how long it might take for them to reach us given the light took 7.5 billions years to get here.
Maybe I can find the piece. I know it is off topic but I was thinking about mass extinctions and other planets.

Good point. There's an attractive binary star system just 8000 light years away that looks pretty enough to astronomers, but as we happen to be viewing it almost directly inline with its rotational axis, and one of the stars is a rapid burning Wolf-Rayet type, a concentrated burst of gamma rays may well be fired directly at us when it goes supernova! It's rather like looking down the barrel of a loaded gun! Nobody can really quantify the risks of these kinds of things yet, all we can go on is past history and a few assumptions about previous mass-extinctions on this planet.

Maybe it really is a big dose of luck that enough time between interstellar catastrophes has given us a chance to evolve to where we are now, but then again; too few mass-extinctions and it appears that evolution might get stuck in a rut. It could well be that the odds for ETCs are greatly lengthened by the need for a particular rate of catastrophe.

[QED]

QED asks ,"Where are they?"
Has all avenues of search been exhausted?If so ,
Have you researched things spiritual to discover, "where are they?"or,is this route not your cup of tea?

Hi earl I understand spirituality to be no more than a state of mind. In these terms I consider myself and many other non-religious non-scientists and scientists like me to be very spiritual in so much as we devote a great deal of time exploring the way the world apparently works and marvelling at its many wonders. I note that there can be a great difference between what's actually going on and appearances, however I see plenty of things happening that clearly have no content beyond that which others are arbitrarily ascribing to them. The spiritual plane seems to be intersected at many points of ignorance, most of which get cleared-up in due course.

If you're suggesting that the reason we currently appear to be alone in the universe has something to do with a supernatural intention, I would like to know how we could tell that from a state of affairs in which were alone for nothing other than natural reasons.

[Beto]

As humanity is on the verge of achieving "invisibility" by means of "metamaterials", who's to say what can be accomplished by an ETC advanced enough to visit us? I can't even begin to imagine the motivations the individuals of such an ETC might have to establish contact.

[earl]

Qed, hello to you
You say--"If you are suggesting that the reason we currently appear to be alone in the universe has something to do with a supernatural intention,I would like to know how we could tell that from a state of affairs in which were alone for nothing other than natural reasons."
You opend with a question,-"I would like to know"-then close the question with ,"alone for nothing other than natural causes."
From that I will save this connection involving planetary isolation for another day.

Have a nice day.

[QED]

As humanity is on the verge of achieving "invisibility" by means of "metamaterials", who's to say what can be accomplished by an ETC advanced enough to visit us? I can't even begin to imagine the motivations the individuals of such an ETC might have to establish contact.

I think we are also gaining the notion that interference is not wise in our own explorations. For example anthropologists know that their very presence will change the behaviour of those who's behaviour they wish to study. NASA goes to great lengths to sterilize the equipment they use to explore potential ecologies and so on. This realization is founded on logical grounds and should therefore represent a universal strategy -- however it only applies when the motivation is the same i.e. passive observation.

As for other forms of "invisibility" the most obvious issue coming out of SETI for me is the fact that the most efficient use of the EM spectrum and use of power is to transmit information with zero redundancy. This is what we approximate with modern digital communications. It has been said that a radio engineer from the 1920's might conclude that there was no intelligent activity in a big city if all he had to go on was his long-wave Amplitude Modulated equipment. Certainly I think that this has the potential to play a big part in accounting for the absence of intercepting "accidental" ET signals -- in our own short technological history we are near to having only made broadcasts of the sort distant SETIs could identify for something like a mere century. This tiny window of opportunity is almost certain to hamper detection when the differences in the staging of evolution and relativistic offsets are considered.

Only a deliberate and highly concerted effort to broadcast a long-term narrow-band EM beacon could be expected to be received at some arbitrary time in the history of the galaxy and that raises its own subtle set of maintenance problems!

[QED]

Qed, hello to you
You say--"If you are suggesting that the reason we currently appear to be alone in the universe has something to do with a supernatural intention,I would like to know how we could tell that from a state of affairs in which were alone for nothing other than natural reasons."
You opend with a question,-"I would like to know"-then close the question with ,"alone for nothing other than natural causes."
From that I will save this connection involving planetary isolation for another day.

Have a nice day.

Well I really would like to know, and if you can tell me but won't then it could spoil my day. But I rather suspect that you're requiring some sort of faith in order to "understand" planetary isolation, in which case I would prefer to opt for simply "not knowing at this time". At least this stance stands no chance of being contradicted by subsequent discoveries -- you know how it goes; truth then has to be mangled into heresy to avoid besmirching the sanctity of faith!!!