Many years ago I first came across what's become known today as the Fermi-Hart paradox that basically asks the question "why is there an apparent contradiction between the high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations ?". This was first asked by Enrico Fermi (physicist) back in 1950.

I just recently saw another similar article which prompted me to think that with the incredible advances in technology we've witnessed since he asked that question, WHY haven't we detected ANY traces or evidence of other alien civilizations ?

When you stop to think about it, this is a truly weird situation. We're told that just in our galaxy alone the estimates range from 100's to 1000's of potential civilizations. if we assume that we're not the sole intelligent species in the galaxy and also not the most highly advanced , then one has to assume that some of those civilizations would be less advanced than ours whilst some would be more advanced.

I suppose that any sufficiently advanced civilization could potentially be using some kind of communication method that we have no idea about and would therefore be effectively "invisible" to us. But surely, any newly emerging technological civilization would be expected to discover electricity and the electromagnetic spectrum and especially the radio wave component and would latch onto that as an easy means of communication ... after all, that's exactly what we did. And without intending to do, we've been broadcasting tv and radio signals out into space for many decades. Other civilizations would be expected to do similar and unintentionally make their presence known to other civilizations. So you'd think that space would be briming with radio traffic.

And yet we've heard not a peep from these (comparable to us) civilizations.
So to me, it seems we have the 3 following possibilities to account for the unexpected radio silence out there.

1. We're the only intelligent species in the galaxy (possibly the universe)
2. There are other civilizations out there but we're the MOST advanced technologically
3. There are other civilizations out there but they're ALL incredibly more advanced technologically and hence, "invisible" to us.

None of the above seems like a really satisfactory answer to me and yet if they're out there, then why aren't we detecting them ?

Anyone got any brilliant ideas or theories to account for this paradox ?

i shall list all aliens civilizations we know of and are likely to find any time soon.







...
short list




maybe they havent contacted us because they dont like us? or maybe because it would mess up whatever progress we made. or maybe they dont exist for whatever reason.









[edit on 29-6-2009 by ELECTRICkoolaidZOMBIEtest]

Zeta Reticuli seems to be where everything thinks the greys are from.

You're missing the point here ... I'm not talking about alien civilizations making the long trip here to Earth ... rather I'm asking (as have others) why we don't pick up ANY radio traffic coming from space ?

We've had radio communications for over 100 years now which means that unintentionally we have revealed our presence to other potential technological civilizations within a sphere of radius 100 light years ... and we're only a new technological civilization.

What about any civilization that discovered radio thousands or millions of years ago ? Their signals would have covered thousands or millions of light years by now and be detectable almost everywhere ... but again not a peep of anyone out there ... WHY ?

Using the supposition that any "aliens" would "evolve" technologically in the same way we did and also "look / listen" for us in the same ways, well, yes, we are the only ones possibly. Being snarky, I have to say that this argument appears to come from the same earth-centric views that have plagued us for centuries. It wasn't soooo long ago that we knew that the sun revolved around the earth, right.

Originally posted by Chemley
Using the supposition that any "aliens" would "evolve" technologically in the same way we did and also "look / listen" for us in the same ways, well, yes, we are the only ones possibly. Being snarky, I have to say that this argument appears to come from the same earth-centric views that have plagued us for centuries. It wasn't soooo long ago that we knew that the sun revolved around the earth, right.

Respectively, I have to disagree with your earth-centric viewpoint.

Any civilization that starts to mature technologically and scientifically will begin to examine the world and universe around them. Inevitably this means that they WILL ... not might ... but WILL discover the electromagnetic spectrum and WILL ... not might ... but WILL learn how to use various parts of this spectrum as a very efficient means of communications amongst themselves. Again, within a few short years of learning about radio waves, we've surrounded our entire planet in a radio network.

There is NO logical reason to imagine that EVERY technological society out there sooner or later discovers radio waves and then doesn't make the logical connection that they can be used for communication purposes or deliberately decides not to use them. How else could a planet spanning civilization communicate amongst it's individuals in the early stages of technology without radio communications ? How would they progress to television broadcasting (o something like it) without knowledge of radio waves ?

Usual suspects: Orion, Sirius, Aldebaran..

Noone pay any attention to the post I made, specifically and clearly stating the answer by a Highly Devoted Physics Professor.

Noone look and see the answer. Just post silliness.

This is impossible, I didn't even click it twice.

This is my second line saying this is an error.

[edit on 30-6-2009 by Republican08]

Originally posted by afoolbyanyothername

---

...radio waves obey the inverse square law and by the time they reach a few hundred light years away are so reduced in power that they are probably indistiguishable from background noise. Only those civilizations that purposely transmitted a focused beam of megawatts intensity continuously for an extended period of time just might stand out from the background ... but what would possess them to do so ?

and

....after just discovering radio waves a little over a hundred years ago, we are already moving beyond them from a technological point of view e.g. laser communication, fibre optics, internet, cable, etc.
So if we can be used as a representative sample, it would seem that the majority of civilizations would discover radio & tv but only use them for maybe a max of 200 years before moving on to other communication methods.

I completely agree with both of these statements.

Here's an analogy to consider (building upon what republican08 said above): We may be like an unknown native tribe in the South American jungles who have yet to discover the "civilized" world. This tribe is sending out messages the best way the know how -- by beating on a drum very loudly -- but nobody outside that tribe hears the drums and nobody is returning the signal with drum beats of their own...

...meanwhile, there are radio and TV signals pervading the air all around them, but they are oblivious to these.

Or, like you said, the radio communication from ET is out there, but we just don't have the ability to resolve it through all of the background noise.



[edit on 6/30/2009 by Soylent Green Is People]

the most obvious answer to the Great Silence is that tech civs are extremely rare or we are unique in our galaxy.

on detecting other civs radio waves. I think when we can detect leaked signals at greater distances the search may become more interesting. Our range hampers us a bit in galactic terms.

If we say there are other civs the answer may be that when a civ reaches the tech singularity they either die or do soemthing else. Like migrate to a parallel universe where they live with other post singularity civilizations.

Personally i think tech civs are rare. There could be only a few in the galaxy that would explain the silence and it would be very difficult for us to detect them

[edit on 30-6-2009 by yeti101]

Probably because Intellegent civilizations dont survive more than a few thousand years. They create some destructive weapon or some catastrophic event happens on there planet the wipes them out. Maybe natures way of keep things balanced.

Or maybe...

Just remember the Dinosaurs. 273 million years of....hunting. No development or intellegence at all. Longest surviving species on the planet. Humans have only been around for 500,000 years and after only 100 years we have the ability to wipe ourselves out 4 times over with Bio weapons or Nukes.

Imagine what weapons we have 1000 years from now?