SETI, where the hell are they?

Originally posted by FabianFnas
I would say that civilisations in our galaxy is very rare.

Based on what? There is no evidence that I am aware of that leads to that conclusion, so either you are guessing, or you have evidence I am not aware of.

Originally posted by twhitehead
Based on what? There is no evidence that I am aware of that leads to that conclusion, so either you are guessing, or you have evidence I am not aware of.

We are talking about civilisations that are using radio technology. We haven't seen anything yet. Our civilisation are spilling out radiowaves in the cosmos, easily detected for anyone with our technology, We would have found anything by now. We haven't.

What is your idea of the L parameter in the Taylor's formula? Do you think it is million of years, or even billion of years?

What is your opinion in the matter? How many technological civilisations do you think exist in out galaxy today?

Originally posted by FabianFnas
We are talking about civilisations that are using radio technology. We haven't seen anything yet.

We haven't looked very hard.

Our civilisation are spilling out radiowaves in the cosmos, easily detected for anyone with our technology,
Not true. If there were tens of thousands of civilisations in our Galaxy spilling out exactly as much radio waves as we do, we would not have seen them.

What is your idea of the L parameter in the Taylor's formula? Do you think it is million of years, or even billion of years? What is your opinion in the matter? How many technological civilisations do you think exist in out galaxy today?
I have no idea. I think it is unwise to make wild guesses about without any evidence.

Originally posted by twhitehead
We haven't looked very hard.

[b]Our civilisation are spilling out radiowaves in the cosmos, easily detected for anyone with our technology,
Not true. If there were tens of thousands of civilisations in our Galaxy spilling out exactly as much radio waves as we do, we would not have seen them.

What is your idea of the L parameter in the Taylor ...[text shortened]... oday?
I have no idea. I think it is unwise to make wild guesses about without any evidence.[/b]

If there were tens of thousands of civilisations in our Galaxy spilling out exactly as much radio waves as we do, we would not have seen them.

Not true. There are simply no natural sources of our radio transmission signature.

I have no idea. I think it is unwise to make wild guesses about without any evidence.

If that was true, we would still live in the dark ages. Imagination is the fuel of science and technology.

Originally posted by FabianFnas
[b]If there were tens of thousands of civilisations in our Galaxy spilling out exactly as much radio waves as we do, we would not have seen them.

Not true. There are simply no natural sources of our radio transmission signature.

I have no idea. I think it is unwise to make wild guesses about without any evidence.

If that was true, we would still live in the dark ages. Imagination is the fuel of science and technology.[/b]

Actually, there are plenty of natural sources of radio waves in the universe, in fact, even in our own solar system. For instance, Jupiter is an intense emitter of radio waves. I would imagine any active Jupiter like planet inside some solar influence would also have radio wave emissions. That is not the only one either. Ionized gasses also give off radio waves.

Here is one source recently found in another galaxy:

https://www.newscientist.com/article/dn18775-mysterious-radio-waves-emitted-from-nearby-galaxy/

Originally posted by sonhouse
Actually, there are plenty of natural sources of radio waves in the universe, in fact, even in our own solar system. For instance, Jupiter is an intense emitter of radio waves. I would imagine any active Jupiter like planet inside some solar influence would also have radio wave emissions. That is not the only one either. Ionized gasses also give off radio w ...[text shortened]...
https://www.newscientist.com/article/dn18775-mysterious-radio-waves-emitted-from-nearby-galaxy/

Yes I know about Jupiter radio transmission. But that is a natural source. If it were inelligent signals, we'd know that.

Seen from outside - the solar system has a very peculiar radio signature. The Solar System without life in any problem wouldn't give a radio specturm like this. It's impossible. The radio signature from the solar system must emanate from intelligence, nothing else. Jupiter doesn't show any intelligence.

Originally posted by FabianFnas
Not true. There are simply no natural sources of our radio transmission signature.

Not true. We simply haven't looked.

If that was true, we would still live in the dark ages. Imagination is the fuel of science and technology.
There is nothing wrong with imagination, and imagining a given number of civilizations out there and asking what the consequences are. It is another thing altogether to make unwarranted assumptions and hold beliefs about how many there are out there - and no, such unwarranted assumptions are not the fuel of science and technology.

Originally posted by FabianFnas
Yes I know about Jupiter radio transmission. But that is a natural source. If it were inelligent signals, we'd know that.

Seen from outside - the solar system has a very peculiar radio signature. The Solar System without life in any problem wouldn't give a radio specturm like this. It's impossible. The radio signature from the solar system must emanate from intelligence, nothing else. Jupiter doesn't show any intelligence.

But there, we run into the wavefront issue and the number of civilizations capable of picking up such signals. Remember, our wavefront has send intelligent signals out about 100 light years into the galaxy in an ever expanding sphere of ever weakening signals.

That means, if there was a civilization out there 1000 light years away, they would not be able to pick up or radiation for another 900 years and would they still have the capability of picking up RF by that time? If they were like Earth people, they would be developing more efficient ways of transmitting information, perhaps by modulating neutrino's or some such non electro magnetic wave kind of communications, maybe by quantum communications not involving RF.

So 1000 years later this civilization has gone beyond the need for RF in the first place and thus will now not pick us up because they are into better things by that time.

That example is of a society 1000 light years away from Earth.

The galaxy is 100 times larger than that however so there could be 100 such civilizations that even if they don't go extinct or some such, could all be going from the technology of RF to that of something much more efficient and so NONE of those people would ever pick us up either.

We are about 25,000 light years from the center of the galaxy so the other edge is about 75 thousand light years away.

A civilization there would have to wait 75 thousand years to ever be able to pick us up with THEIR radio telescopes. I don't think humans will be the same 75K years from now.

And if they get excited about hearing our signals, they decide to send something back, a galactic howdy, now it is 150 thousand years in our future before we get that signal. You think there will actually be humans here that far into the future?

Originally posted by sonhouse
But there, we run into the wavefront issue and the number of civilizations capable of picking up such signals. Remember, our wavefront has send intelligent signals out about 100 light years into the galaxy in an ever expanding sphere of ever weakening signals.

That means, if there was a civilization out there 1000 light years away, they would not be able ...[text shortened]... efore we get that signal. You think there will actually be humans here that far into the future?

Well, you are right in everything. But that doesn't change my point of view. Because your view doesn't contradict mine.

When our signal reach and is detected by another technological civilisation out there, perhaps we have blown ourselves to pieces. This doesn't mean that we don't live and prosper now. There should be plenty of wavefronts out there for us to pick up - but there isn't, not a sign of evidence.

We can, as twhitehead says, avoid speculations. Or we can make use of our fantasy to speculate. And we can all fantasize different as we all are different people.

I say that intelligent technological civilisations in our galaxy are rare.
What do you say?

Originally posted by FabianFnas
There should be plenty of wavefronts out there for us to pick up - but there isn't, not a sign of evidence.

We haven't looked. Just because your eyes are closed it doesn't mean the light is off.

Originally posted by FabianFnas
Well, you are right in everything. But that doesn't change my point of view. Because your view doesn't contradict mine.

When our signal reach and is detected by another technological civilisation out there, perhaps we have blown ourselves to pieces. This doesn't mean that we don't live and prosper now. There should be plenty of wavefronts out there for ...[text shortened]...

I say that intelligent technological civilisations in our galaxy are rare.
What do you say?

I think techo civilizations are going to be rare in our galaxy, but say there are 10 around the milky way and that average holds up throughout the universe, that leaves literally billions of such civilizations present in the universe.

Image life on a planet like Venus with such a thick atmosphere that stars are not visible. It might never occur to them that there are any bodies beyond their own planet. So they wouldn't be looking or listening for any signs of life elsewhere.

Originally posted by FabianFnas
Well, you are right in everything. But that doesn't change my point of view. Because your view doesn't contradict mine.

When our signal reach and is detected by another technological civilisation out there, perhaps we have blown ourselves to pieces. This doesn't mean that we don't live and prosper now. There should be plenty of wavefronts out there for ...[text shortened]...

I say that intelligent technological civilisations in our galaxy are rare.
What do you say?

Our RF wavefront is barely 200 light years in diameter, that is a pretty small slice of the galaxy, so even if we have a detection by a techno civilization and they reply it will still be the year 2200 or so before we get a signal, And of course that delay goes up by two years for every year that goes by. If a techno civilization picks us up and they are 1000 ly away, which is still a small slice of the galaxy, it would be the year 4000 or so before we know about them. not a great chance of a detect.

Originally posted by moonbus
Image life on a planet like Venus with such a thick atmosphere that stars are not visible. It might never occur to them that there are any bodies beyond their own planet. So they wouldn't be looking or listening for any signs of life elsewhere.

unless they first invent flying machines and then later discover that the higher you go, the thinner the air. That is bound to get some curious to extrapolate what would happen if you keep going up ever higher; will the air eventually become so thin as to cease to exist? So they keep doing experimental flying tests to go ever higher to see what happens. But then, via flying one to very high altitude and observing or taking pictures of what is outside, they discover that, if you go high enough, there appear to be many mysterious glowing dots above (stars ) . That gets them really curious to know what they are so they start doing more research sending aircraft ever higher to find out what they possibly could be. They ask themselves questions like; Are they some kind of firefly? are they just a mirage? are they camp fires on floating upside-down land masses? how far away are they? Are they good to eat? can we fly high enough to pick one to see if it is good to eat? why is one of them vastly brighter than the rest?

This could be the bases of a science fiction novel.

Originally posted by humy
unless they first invent flying machines and then later discover that the higher you go, the thinner the air. That is bound to get some curious to extrapolate what would happen if you keep going up ever higher; will the air eventually become so thin as to cease to exist? So they keep doing experimental flying tests to go ever higher to see what happens. But the ...[text shortened]... ne of them vastly brighter than the rest?

This could be the bases of a science fiction novel.

There are several things that would help such a civilization. One is a thick atmosphere is not opaque in all wavelengths so they might have eyes that are more sensitive in the wavelengths that allow the deepest penetration of sight in that atmosphere, so when they develop optics, they would concentrate first on those wavelengths that work the best for them. IR can penetrate more kinds of smokey atmospheres than our optical wavelengths so I think they would have a chance of seeing stuff outside their world. For instance, their sun would be the first thing good optics would resolve and realizing there is SOMETHING out their not their planet that would be a real incentive to investigate further. Look at us trying to suss out gravity waves. We started with those aluminum cylinders with piezo pickups on them thinking maybe that would work, only off in sensitivity by a factor of a billion or so but they started better designs and we are near quantum limits and still finding improvements in the sensitivity and it seems clear we will succeed sooner or later at that energy band. So it would go with an advanced civilization in a thick smokey dusty atmosphere.