We could, in theory, detect the 'fringes' of signals, so I am not assuming they know we are here. Frankly I don't rate the radio signal search as being either important or likely to succeed. We would be more likely to pick up the edges of a laser signal.
As the article stated, it's likely that we don't have the equipment (perhaps the technology) to listen for signals even as close as our closest star, unless that signal is being focused directly at us. And that's also provided we're on the right frequency at the right time.
Since it is almost entirely through the electromagnetic spectrum that we know anything about the universe then it is close to certain as you can get that any advanced civilisation would have radio. However, as I say, I don't place much confidence in this.
But like I said before, there are too many variables to use the absence of this particular evidence as a mark against their existence. So I agree with you in that I can't place confidence in it.
And again, I see no reason to be certain that an advanced race would have or use radio.
The smaller the number of civilisations the weaker my argument becomes. I took a very weak position to demonstrate that even in this case my argument holds water. If the number is say one million then their apparent absence becomes even more staggering.
If the stars were as close together as the planets in our solar system are, then yes, you'd have a valid argument. But we're talking distances that are hard to fathom. The galaxy alone is 100,000 light-years across, and there are between 200-400 billion stars in it. So a million civilizations in the galaxy would still make for a staggering ratio of stars-to-civilizations. I mean, we might very well be the only civilization within 100 light years, in which case no civilization beyond ours would have noticed the high radio output from our system until, for all intents and purposes, today.
So there's nothing staggering about the silence.
A Kardashev Type II or III civilisation should reveal itself very clearly, yet there is not a Dyson sphere in sight. Why not?
Because both of those items you've mentioned are both hypothetical and highly speculative. I mean, we haven't heard from any Klingons yet, either...
Because the principle is that we pick up stray signals from other civilisations.
Are you not reading anything that's being written here? Even with our most sensitive listening devices, we'd only be able to pick up our own heavy EM output at a distance of 0.3 light years. So unless the radio signal was
directed at us, we'd stand no chance of picking up anything.
The only relevance is then how long they have had radio, not how long we have had it. I have pointed this out. Oli has pointed this out, but you keep coming back to it.
I'll keep coming back to it because you are both missing the point. One more time, and hopefully this sinks in: it matters how long we've had the technology, because it matters how long we've been listening, and how well we are capable of listening. Of course it matters how long they've had it, but to say it doesn't matter how long we've had it simply displays that you have no working knowledge whatsoever of how it works. So far all I've heard you or Oli say is that we should be picking up "stray signals". And as I've already demonstrated, that's impossible at the distances we're talking. We aren't capable of picking up "stray signals" at even the distance between ourselves and our closes neighbor.
On any sound scientific basis UFOs are not ETs on a flying visit. I don't rule it out, it is simply not a viable hypothesis.
That's simply not true at all. There is no evidence that the UFO sightings are of extraterrestrial origin. That's as far as the answer goes. They very well might be alien. There's simply no way to know if they are.
And I have to ask how you invoke "sound scientific basis" when you don't even know that we're not capable of intercepting the stray radio transmissions of alien civilizations beyond 0.3 light years away?
It is a well established concept. Send out slow ships in every direction to candidate systems with frozen embryos and Von Neuman construction probes. The resultant community is ready to repeat the process within at most a couple of thousand years. If the slow ships can attain 5% of c then you can do the whole galaxy in 1 million years. If you go even slower it merely extends the time to say five million years.
It's totally hypothetical. Quite different than your assertion that "we
can populate the galaxy in 1 million years".
And I'm sorry, but for someone who knocks UFOs for not being "viable hypothesis", you certainly do fancy yourself other elements of outright science fiction.
It still leaves the question, where is everyone?
They might be all around us. If you had any real understanding of the difficulties of communicating and traveling across such vast distances, you'd understand that it's perfectly acceptable for us to have no evidence of other civilizations as of yet.
I think it's clear that in order to find life elsewhere, you have to be the one to go looking for it, as opposed to waiting for it to stumble across you.
Fermi was not talking about radio contact. Fermi was talking about visits. That is what you N.fan seem determined to ignore. I didn't bother reading the link till just now, assuming that the wikipedia article would get it broadly correct, which they did.
It is thoughtless to prattle on about radio when Fermi was talking about visits.
Which makes the paradox--which YOU offered up, by the way, as an argument against my personal belief that the universe is too large and stars too many for us to be alone--even more startlingly ignorant. Fermi of all people should have known that interstellar travel is a long process, and in most cases would be downright impossible. He honestly expected there to be alien visitors? And you supported this? Are you serious? How is it that someone who considers himself a "retard basher" and takes pleasure in pointing out the so-called shortcomings of other posters, relies almost entirely on hypotheticals? And even then, only the most outrageous and far-off hypotheticals?
