have they found anything?

[JoeTheJuggler]

Yet. We shouldn't be expected to colonise the galaxy seeing that the first rocket wasn't invented until very recently by Werner Von Braurn. [spel] Since then we have landed a man on the moon. Imagine what the next couple of centuries will bring travel wise.

Yes, I can imagine such things. However, you can't make a logical argument based on the assumption that you know what will inevitably happen, because you don't know they will happen.

Again, the argument that Fermi's Paradox proves we are alone is logically flawed because it makes assumptions like this.

We may never achieve interstellar travel at all. We may go extinct or our civilization collapse before that is possible. Or we may continue on but find that interstellar travel never becomes economically feasible. Or it could be feasible, for whatever reason we may not be motivated to do it. (These are all points I've made before, which is why your post about how recently we started experimenting with rockets--it's Werner Von Braun--does nothing to bolster your argument. It still relies on assumptions we don't know to be true.)

ETA: Please note: I recognize and accept that it is also possible that it could be economically feasible to colonize the galaxy or otherwise make evidence of a civilization's existence ubiquitous in the galaxy. I'm not contesting that point. I'm pointing out, simply, that there are other plausible explanations for Fermi's Paradox other than that ETIs do not exist.

There is no hint of us collectively deciding not to expand in to space now.

This is all backwards. It's as if you assume if we don't make some sort of decision not to, we will naturally or automatically inevitably colonize the galaxy without making a decision to do so.

We don't know that we, or any possible ETI civilization, must inevitably achieve interstellar travel and make evidence of our existence ubiquitous in the galaxy. The argument that says the only explanation for Fermi's Paradox is that ETIs do not exist rests on that assumption, which is why it is logically flawed.
_______

Recovering Yuppy, I suggest you take a deep breath and calm down.

You have accused me of sidestepping a question I clearly answered. You have accused me of not understanding your posts, when in fact I have understood clearly, despite your sloppy use of language.

You've accused me of "flooding" the thread and refusing to understand your arguments. In fact, I understand the argument that the lack of evidence proves the non-existence of ETIs. I've just been pointing out that it's logically flawed. It depends on several assumptions that we don't know to be true.

I'm not arguing that I know ETIs exist or that I know we are not unique in the galaxy. My position is and has been that we don't know the answer to these questions. I'm in favor of continuing to explore the universe and in particular to gather information that might help us answer these questions. (For example, the Kepler mission is very exciting.)

 

[JoeTheJuggler]

I don't think any of your other points need to be addressed for a fiftieth time.

What are you talking about?

In order to refute the argument I've made, it would be necessary to prove that the only possible explanation for Fermi's Paradox is that ETIs don't exist. To do that, you would have to show that each of my numbered points is impossible.

No one has done that, much less addressed those points 49 times!

If what you say is true, it should be no problem for you to address each of those points once anyway, and show how each of them is impossible.

See my ETA in the previous post. I'm not saying, nor have ever disagreed with, the proposition that interstellar travel might be feasible. I'm only pointing out that it's not inevitable. There are other possible explanations.

So the fact is we simply don't know whether ETIs exist (or even questions about how rare or common they might be if they do exist).

 

[Roboramma]

And you were replying to my statement that there is no such thing as a free spacecraft.

And he pointed out that in a way there is. At least, there's a way for a space colony to become an interstellar craft for free. To be more precise, it's possible to choose a body to build a colony on such that, at no more cost than building a colony on any other body, the colony will drift to another star.

I think it's a good point, actually. Some comets and other bodies that come close to earth may have interstellar trajectories that intersect other stars.

I would like to say, though, that there is an opportunity cost, in the sunlight that will be denied during the journey, and if the journey is tens of thousands of years long, that's not meaningless. But it can certainly be made up for by not having to compete for resources at the new star.

Again, there is no model where an interstellar spacecraft is free. My point is that this cost could make the launch of such craft not feasible. This is a plausible possible explanation for Fermi's Paradox. Therefore Fermi's Paradox does not point to the conclusion that there are no ETIs.

I think you missed the part where he explained what he means by free interstellar craft. Again, he's suggesting choosing an appropriate body for doing something that we'd already be doing anyway (living in space) such that it happened to intersect another star. As we don't have to do any of the acceleration/deceleration, the interstellar travel part of the cost is free. The other costs are costs that would have been born by any space colony anyway, which is what he means by saying that there are no incremental costs.

I again agree that this is a meaningful point, but as I said, I do think that the opportunity costs are meaningful and it's conceivable that people simply won't choose to do interstellar travel if it means being away from your main power source for tens of thousands of years. It's also likely that any such advanced civilization will be very interdependent, the costs of being separated from that civilization and it's products will also be prohibitive.
The degree to which either of those objections are meaningful, though... well, I'm not confident that it's enough to argue that we won't go interstellar, but personally I think we very likely will.

Yes, and I indicated that I understood your intent, even though what you said wasn't that. (You said humans have never made a collective decision, which isn't true. And, in the context, that's really what we're talking about. A large investment would require a collective decision, but not necessarily a unanimous one.)

Look back at the context, he said that in response to the suggestion that humans would make a conscious choice not to go interstellar for moral reasons. All it takes is a few people disagreeing to change that.
He's not saying that interstellar travel requires a unanimous decision, he's saying that purposely not doing interstellar travel for a cultural or moral reason requires a unanimous decision, and that such unanimous decisions are not things humans do.

 

[Roboramma]

We may never achieve interstellar travel at all. We may go extinct or our civilization collapse before that is possible.

While I agree with this, I don't think it works here because if this is the general case, it means that technological civilizations last a very short time, and thus at any particular point in time (like now) there are unlikely to be more than one.

Or we may continue on but find that interstellar travel never becomes economically feasible.

This I agree with in principle. Though personally I think it likely that it will become economically feasible, anyone who thinks that's certain is fooling themselves.

Or it could be feasible, for whatever reason we may not be motivated to do it. (These are all points I've made before, which is why your post about how recently we started experimenting with rockets--it's Werner Von Braun--does nothing to bolster your argument. It still relies on assumptions we don't know to be true.)

I'd like to point out that this is a rather meaningful point as well. In particular as our advancing technology effects us culturally the drive to procreate, the need for ever more resources, etc. may simply no longer be there, and thus the drive to move to other stars may disappear as well. Again I think anyone who suggests that they know what humans 1000 years from now will want is fooling themselves.

 

[Roboramma]

In reference to the Fermi Paradox I also think we need to consider what we mean by technological civilization. Our technology is advancing exponentially, but that doesn't have to be the case. Homo Erectus had technology at the hand ax level that didn't advance for millions of years. (I think it's homo erectus, anyway, one of our ancestors. After the technology had advanced, very slowly, for a long time, its was steady for a long time, then modern humans came along and started making different hand axes, and soon after, even better ones, etc.)

Could the same sort of very slow technological advance lead to an agricultural or even industrial civilization? Could a species be extremely good at figuring out how to use other organisms as tools (ie. through artificial selection using the biological products of other organisms as tools), but not be good at doing physics, for instance?
I don't know that that sort of technological civilization is likely to be more rare than our own, but it would fit my definition of ETI.

For this and many more reasons I still agree with Joe that the evidence simply isn't strong enough one way or the other and the only conclusion at this point is that we don't know.

I do think, though, that in the future we will have more and more evidence and at some point, whether we make contact or not, we may be able to say one way or the other. Not yet, though.

 

[JoeTheJuggler]

I think you missed the part where he explained what he means by free interstellar craft.

I didn't miss it. He said that the incremental costs (as you say, the cost beyond the humongous cost of building a colony) might be zero. See below:

I again agree that this is a meaningful point, but as I said, I do think that the opportunity costs are meaningful and it's conceivable that people simply won't choose to do interstellar travel if it means being away from your main power source for tens of thousands of years.

Which is exactly why I said there's no such thing as a free lunch spacecraft.

That saying is invoked to address opportunity costs. (Even if someone pays for your lunch, it's still not really free to you.) (ETA: We don't know what economic considerations there might be. It is possible that such a project never becomes economically feasible.)

The degree to which either of those objections are meaningful, though... well, I'm not confident that it's enough to argue that we won't go interstellar, but personally I think we very likely will.

All I'm arguing is that it's not inevitable that we will achieve interstellar travel or that any other ETIs that may or may not exist will necessarily have achieved whatever it takes to make evidence of their existence ubiquitous in the galaxy before we came along to notice that evidence wasn't there.

Look back at the context, he said that in response to the suggestion that humans would make a conscious choice not to go interstellar for moral reasons. All it takes is a few people disagreeing to change that.
He's not saying that interstellar travel requires a unanimous decision, he's saying that purposely not doing interstellar travel for a cultural or moral reason requires a unanimous decision, and that such unanimous decisions are not things humans do.

And I pointed out that the argument he is defending requires a lot more than not making a unanimous decision not to travel. He clearly implied that if we do not make such a decision, we will certainly achieve interstellar travel. That simply doesn't follow.

Again, I'm not arguing that we will not achieve interstellar travel. I'm also not arguing that it's impossible for an intelligent civilization to make colonize the galaxy (or otherwise make evidence of their existence ubiquitous throughout the galaxy). I'm just arguing that it's not inevitable, and the lack of evidence that it has happened does not argue for the non-existence of ETIs.

 

[JoeTheJuggler]

While I agree with this, I don't think it works here because if this is the general case, it means that technological civilizations last a very short time, and thus at any particular point in time (like now) there are unlikely to be more than one.

No--it's just saying it may be possible that no civilization lasts long enough to achieve interstellar travel (or whatever it takes to make evidence of their existence ubiquitous in the universe). There may be quite many civilizations.

This I agree with in principle. Though personally I think it likely that it will become economically feasible, anyone who thinks that's certain is fooling themselves.

And that's exactly the point I've been making. The argument that amb put forth is that Fermi's Paradox can only be explained by the non-existence of ETIs. I've been pointing out that that conclusion depends on a great many assumptions that may be summarized as the assumption that if any ETIs exists that they must certainly have made evidence of themselves ubiquitous in the galaxy.

I'd like to point out that this is a rather meaningful point as well. In particular as our advancing technology effects us culturally the drive to procreate, the need for ever more resources, etc. may simply no longer be there, and thus the drive to move to other stars may disappear as well. Again I think anyone who suggests that they know what humans 1000 years from now will want is fooling themselves.

Thanks. And it's one of the points on my numbered list that none of my detractors have yet addressed--not even once.

Exactly. Even if the technology is possible, and a civilization lasts long enough to develop that technology, and it's economically feasible to use, it could be that a civilization lacks the motivation to use it. We simply don't know.

And the argument that the lack of evidence at this point means that ETIs don't exist is based on the assumption that we know with certainty.

 

[RecoveringYuppy]

I think it's a good point, actually. Some comets and other bodies that come close to earth may have interstellar trajectories that intersect other stars.

And the stars themselves are in motion. Over immense time periods there are going to be close approaches.

I would like to say, though, that there is an opportunity cost, in the sunlight that will be denied during the journey, and if the journey is tens of thousands of years long, that's not meaningless.

But even that doesn't have to be a cost to interstellar migration. If some colonies have artificial sources of light and power because they are mining the Oort cloud then that won't be an incremental cost caused by them embarking on an interstellar journey. Migration may come as a side effect of other activities without ever even being an explicit intent to migrate.

This I agree with in principle. Though personally I think it likely that it will become economically feasible, anyone who thinks that's certain is fooling themselves.

Firstly, I'm not so sure about that. We're doing more and more of it now. It's becoming cheaper as we do it. And there's a very strong case that simply getting up 90 miles is the most expensive part. What does it cost to get up to orbit 90 miles above the planet? How much more do you spend to go the next billion miles to the outer planets?

We've already developed plausible plans for building a self sufficient colony in space. If we do that we are going to be living in a solar system where some people find it cheaper to go almost anywhere in the solar system except for the surface of planets, including returning to Earth. That's going to change things.

Secondly, even if it's economically prohibitive for some races to explore the galaxy is it going to be so for all of them? All races will be born in circumstances that make it expensive? Not one of them ever arises on a planet with lower escape velocities? None of them ever have a satellite that's more amenable to colonization? None of them are ever closer to a neighboring star?

And I pointed out that the argument he is defending requires a lot more than not making a unanimous decision not to travel. He clearly implied that if we do not make such a decision, we will certainly achieve interstellar travel. That simply doesn't follow.

I didn't imply that. I meant it exactly the way Roborama just explained it to you.

Look back at the context, he said that in response to the suggestion that humans would make a conscious choice not to go interstellar for moral reasons. All it takes is a few people disagreeing to change that.
He's not saying that interstellar travel requires a unanimous decision, he's saying that purposely not doing interstellar travel for a cultural or moral reason requires a unanimous decision, and that such unanimous decisions are not things humans do.

 

[JoeTheJuggler]

But even that doesn't have to be a cost to interstellar migration. If some colonies have artificial sources of light and power because they are mining the Oort cloud then that won't be an incremental cost caused by them embarking on an interstellar journey. Migration may come as a side effect of other activities without ever even being an explicit intent to migrate.

How are those things not costs?

At any rate, the argument depends on more than "may" or "might be".

It is still possible that interstellar spacecraft never become economically feasible. In other words, there are explanations for Fermi's Paradox other than that ETIs don't exist.

What does it cost to get up to orbit 90 miles above the planet?

Quite a lot.

How much more do you spend to go the next billion miles to the outer planets?

More than it costs to get up to orbit 90 miles and not go the next billion miles. The former is a subset of the latter.

We've already developed plausible plans for building a self sufficient colony in space. If we do that we are going to be living in a solar system where some people find it cheaper to go almost anywhere in the solar system except for the surface of planets, including returning to Earth. That's going to change things.

Yes, that's the one thing about the future we do know--things will change. But we don't know how.

Secondly, even if it's economically prohibitive for some races to explore the galaxy is it going to be so for all of them?

I am not claiming proof that it is, merely that it's a possibility. Yes, it is possible that civilizations don't last long enough to achieve interstellar travel. It's possible that they last long enough but that it's never economically feasible. It's possible that it's at least sometimes economically feasible, but that no ETI is ever motivated to do it (or to do it to the extent that evidence of their existence is ubiquitous in the galaxy).

All races will be born in circumstances that make it expensive? Not one of them ever arises on a planet with lower escape velocities? None of them ever have a satellite that's more amenable to colonization? None of them are ever closer to a neighboring star?

Most of these questions aren't relevant, but yes, all those things are possible.

Living on a planet with lower escape velocity, having a satellite that's amenable to colonization, being nearer to the next star would still not make the ubiquitous evidence of such a civilization

I didn't imply that. I meant it exactly the way Roborama just explained it to you.

In that case, it's irrelevant. You certainly made it sound like you were countering my argument. (I'm not sure who raised the moral objection idea, but yes, it is possible that a civilization has a unanimous moral objection to colonizing the galaxy. My point was the more general idea that it could be, for reasons we don't know or can't conceive of at this point, that while such advanced civilizations might be able to do whatever it takes to make evidence of their existence ubiquitous in the galaxy, they will lack the motivation to do so.)

 

[A. Zaitsev]

NewScientist Magazine, No 2744 (23 Jan 2010)

Cover
www()newscientist()com/currentcover()jpg

and three articles are about Interstellar Radio Messages to ETIs:

Exolanguage: do you speak alien?
www()newscientist()com/article/mg20527441.300-exolanguage-do-you-speak-alien.html

Earth calling: A short history of radio messages to ET
www()newscientist()com/article/dn18417-earth-calling-a-short-history-of-radio-messages-to-et.html

Hello ET, we come in peace
www()newscientist()com/article/mg20527442.600-hello-et-we-come-in-peace.html

 

[JoeTheJuggler]

For convenience (active links):

NewScientist Magazine, No 2744 (23 Jan 2010)

Cover
www.newscientist.com/currentcover.jpg

and three articles are about Interstellar Radio Messages to ETIs:

Exolanguage: do you speak alien?
www.newscientist.com/article/mg20527441.300-exolanguage-do-you-speak-alien.html

Earth calling: A short history of radio messages to ET
www.newscientist.com/article/dn18417-earth-calling-a-short-history-of-radio-messages-to-et.html

Hello ET, we come in peace
www.newscientist.com/article/mg20527442.600-hello-et-we-come-in-peace.html

 

[amb]

We have been sending messages into space for around fifty years now. What it means is that if there are beings of some kind out there remotely like us, they are at least further away than 25 light years. We really have a long way to go before we know for sure whether ''are we alone?''

 

[A. Zaitsev]

We have been sending messages into space for around fifty years now. What it means is that if there are beings of some kind out there remotely like us, they are at least further away than 25 light years. We really have a long way to go before we know for sure whether ''are we alone?''

First IRM = Interstellar Radio Message was sent in 1974, that is 2010-1974=36 yeasrs ago, only...

Also, please read:

Calculations show that, at an interplanetary distance,
we can discover an intelligence with a
level of development that is similar to that of
Earth’s civilization. We can make this discovery
without transmission of special radio signals by
extraterrestrial intelligence, by only the radio
emission of various radio devices. However, we
cannot discover such intelligence at distances
starting from the nearest star.

Thus, in order to discover intelligence situated
near a certain star via measurements in a radiofrequency
band, this intelligence should use
radio transmitters that are significantly more
powerful than those used on the Earth (while it is
not clear for which needs this increased power
could be required) or this intelligence should
radiate special signals that are intended to make
its presence known.

Quote from:

docs()google()com/fileview?id=0B3dfv8xNOu48OTZmNTdlODAtODFiNi00MmQ2LWJjOTAtZDE1OTBkNjMzOGE0&hl=en

 

[LarianLeQuella]

We have been sending messages into space for around fifty years now. What it means is that if there are beings of some kind out there remotely like us, they are at least further away than 25 light years. We really have a long way to go before we know for sure whether ''are we alone?''

For some reason, maybe AMB thinks the inverse square law doesn't apply to omnidirectional signals? Our own civilization is virtually undetectable with our best technology beyond the orbit of Pluto. Of course, this has been pointed out ad nauseum...

The signals Dr. Zaitsev points out are focused signals, and as best as I can tell, none of them have even brushed by any solar systems that may be in their way. So for all intents and purposes, our civilization has sent out exactly zero signals that are receivable by anyone at this moment.

And Dr. Z's link: http://docs.google.com/fileview?id=...AtODFiNi00MmQ2L WJjOTAtZDE1OTBkNjMzOGE0&hl=en

 

[JoeTheJuggler]

We have been sending messages into space for around fifty years now. What it means is that if there are beings of some kind out there remotely like us, they are at least further away than 25 light years.

Not really. Our broadcast signals (like TV) would be undetectable beyond our solar system, and these other signals are narrow beams directed at specific targets. Also, even if a signal were received, you need to allow time for a reply. And that's making the assumption that an ETI that receives a signal will necessarily reply. (There's a movement here on Earth that says we shouldn't reply if we receive a signal.)

Even so, the volume of space of a radius 25 l.y. is a teeny-tiny part of the volume of the galaxy.

We really have a long way to go before we know for sure whether ''are we alone?''

Yes. That's pretty much what I've been saying all along. At best it's premature to claim that we are alone.

At worst, as with your argument based on Fermi's Paradox, it's illogical.

 

[amb]

I found this video very interesting and thought provoking. If you have a half hour to kill, watch it.
http://www.veoh.com/collection/SpaceTV/watch/v455817CbpAAc78