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Boris Godunov
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Portland, OR
Aug 2001
time: 00:37
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quote:
Originally posted by Dauphin
We are not discussing meaningful contact, we are discussing detection.
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Whatever, but distance is still a major consideration when you're talking some species 10,000 ly away as opposed to one 4 ly away. The further away a sentient species is from us, the less likely detection will be, simply based on the fact that any intelligent species is going to concentrate detection efforts in nearby star systems as opposed to ones halfway across the galaxy. The reason "meaningful contact" is important is that another species presumably wouldn't be so bothered about detecting intelligent life that was so far away it couldn't have meaningful contact. What would really be the point of that?
quote:
@Boris Gudonov: If the alien race was actively searching for other intelligences, they would presumably leave a probe in each system potentially capable of supporting life permanently. |
And again, depending on how distant the alien race was, the likelihood of said probe being here can be remote. There might be 400,000,000,000 stars in our galaxy to check out. Even with a million probes, the odds of them finding our star are remote.
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Dauphin
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Caught in a tuna net
Jan 1970
time: 05:37
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quote:
Originally posted by Boris Godunov
Whatever, but distance is still a major consideration when you're talking some species 10,000 ly away as opposed to one 4 ly away. The further away a sentient species is from us, the less likely detection will be, simply based on the fact that any intelligent species is going to concentrate detection efforts in nearby star systems as opposed to ones halfway across the galaxy. |
So you are saying that because there are nearer stars that can be inspected an alien race will inspect them first? Certainly very likely. This does not mean that its the distance or travel time that is important though. This is what I have been driving at- If stars were spaced on average 1 light day apart (meaning that a star 4 light years aways was the equivalent of 6,000 light years away in our present galaxy) do you think that a star 4 light years away would be the first choice destination? From your post I would think you would say no and I would agree. Its actual distance has not changed, neither has the time it takes to reach there.. From this would you not agree that its not the absolute distances involved that are of first importance.
Edit -
quote:
The reason "meaningful contact" is important is that another species presumably wouldn't be so bothered about detecting intelligent life that was so far away it couldn't have meaningful contact. What would really be the point of that? |
So you think it not worth finding intelligent life unless its with a couple of hundred light years? I would think any discovery would be welcome at the present time, and even more so if nothing is found within our galactic neighbourhood.
Last edited by Dauphin on 05-07-2004 at 00:19
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Boris Godunov
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Portland, OR
Aug 2001
time: 00:37
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quote:
Originally posted by Dauphin
So you are saying that because there are nearer stars that can be inspected an alien race will inspect them first? Certainly very likely. This does not mean that its the distance or travel time that is important though. |
It does matter, though, as the alien race does not have limitless resources (they're not gods, as far as we know), and you reach a point of diminishing returns whereby exploring out a great distance isn't going to be fruitful. That's why I brought up what would be the use of finding an intelligent species that was so far away there couldn't be "meaningful contact." Why would an advanced raced expend so much effort to find something that would serve no purpose?
quote:
This is what I have been driving at- If stars were spaced on average 1 light day apart (meaning that a star 4 light years aways was the equivalent of 6,000 light years away in our present galaxy) do you think that a star 4 light years away would be the first choice destination? From your post I would think you would say no and I would agree. Its actual distance has not changed, neither has the time it takes to reach there.. From this would you not agree that its not the absolute distances involved that are of first importance. |
But stars are not spaced average 1 light day apart, they're spaced many, many light years apart. When you get down the practical physics, it only makes sense that the further a star system is from an alien race, the less likely it will be they will explore said system, especially when you have hundreds of billions to explore.
To reverse your scenario, let's talk about exploring other galaxies. Given enough time, sure, you could get a probe from one galaxy to another. But would this be of any practical or scientific use? How would you even get the data from it? So isn't the distance between galaxies an inhibiting factor for sending probes to them?
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DanS
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Kickball Capital of the World
Jan 1970
time: 00:37
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The universe is a mind-blowingly big place. Admittedly, doing the probe thing on a 156 billion ly diameter space would be impossible. But it seems quite doable on the 100,000 ly diameter milky way galaxy containing 400 billion stars and some galaxies in our local area.
The idea is that these probes would self-replicate, i.e., would require no additional resources from Earth other than listening in. Indeed, the probes would populate space even if human beings no longer existed. However, it seems likely that we would send out new probe revisions every year to keep up with technology or to survey new aspects of these star systems.
Last edited by DanS on 05-07-2004 at 01:41
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Last Conformist
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of Calakmul
Jul 2003
time: 06:37
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Boris Gudonov
quote:
And again, depending on how distant the alien race was, the likelihood of said probe being here can be remote. There might be 400,000,000,000 stars in our galaxy to check out. Even with a million probes, the odds of them finding our star are remote. |
A million probes, however, are very few. As I've tried to show in my previous posts, for a civilization capable of building self-replicating interstellar probes - and from our present technological horizon, that does not appear to be a very difficult feat - it would be relatively easy to put a probe in orbit around every star in the galaxy.
Now, you might argue that there might have not been any such civilizations around 40 million years ago, but there might be plenty now. This is possible, but hugely unlikely; the galaxy hasn't changed noticeably during the last 40 million years, and the civilization density would be expected to be much the same. If there weren't any around 40 million years ago, we should expect it to be next to none around today.
(I appear to've commited some arithmetic error in arriving at 18 million years, BTW; to reach 400,000,000,000 stars in the way I described, we'd rather need 39 million years. Does not change anything wrt my argument, however; this is still a short time on the galactic timescale.)
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The Andy-Man
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Tory Party of 'Poly
Jul 2001
time: 05:37
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Firstly, who says these aliens have the same life span as us? Perhaps living to the ripe old age of 163,857 earth years is expected?
Secondly, there are so many stars in so many galaxies, that some forms o life MUST be somewhere.
Thirdly, Given that human life on this planet is reletivly young, and even life on this planet is fairly recent, many probes may well have passed and missed us.
Forthly, we are all working on the presumption that the mand us can observe eachother. Maybe they exist only in a 2 dimentional world, or a 7 dimensional world etc, and so their phyical laws and ours are incopatible,
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Odin
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Biology Nerd at Minnesota State University Moorhead
Sep 2000
time: 23:37
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quote:
Firstly, who says these aliens have the same life span as us? Perhaps living to the ripe old age of 163,857 earth years is expected? |
Good point. But I don't think would live for quite THAT long. 
quote:
Secondly, there are so many stars in so many galaxies, that some forms o life MUST be somewhere. |
Other galaxies are irrelavent, they are to distant to contact. Also, most planetary systems are uninhabitable to everything besides the equivalent of bacteria and protozoa.
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Thirdly, Given that human life on this planet is reletivly young, and even life on this planet is fairly recent, many probes may well have passed and missed us. |
I think the same thing, Civilizations don't pop up at the same time.
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Last Conformist
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of Calakmul
Jul 2003
time: 06:37
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quote:
Originally posted by The Andy-Man
Secondly, there are so many stars in so many galaxies, that some forms o life MUST be somewhere. |
Well, only if the chances of life arising on a planet are high enough. From our present knowledge it seems unlikely, but it's for all we know possible that the origin of terrestrial life was a freak occurence, with a probability of say one in 10^80 (10^80 happens to be the approximate number of electrons in the observable universe).
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Thirdly, Given that human life on this planet is reletivly young, and even life on this planet is fairly recent, many probes may well have passed and missed us.
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I don't know if terran life can be said to be "fairly recent"; it's been around for closer to 4 billion years, which is an appreciable amount of time even on a galactic time scale. During that time, for instance, the average metallicity has risen enough to affect planet formation.
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Darkstar
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Huntsville, AL, USA
May 1999
time: 23:37
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quote:
Originally posted by Boris Godunov
Um, but we have experts in in physics. They're called physicists. Might want to read something from them sometime.
The economics are certainly considerable, but that's nothing compared to the physical possibility. Again, talk to the physicists. If, as DanS mentioned, the theoretical max speed of an unmanned object is 1/10 c., then at that speed, things will take a long time to get anywhere and longer still to relay information back. |
I do on occasion, Boris. You might want to consider it yourself sometime. Can be very interesting.
First off, 1/10 c is not the max speed of an unmanned object. If people want to go do some digging on published studies of cost and feasibility that have been done for NASA, we can get closer to c then just 0.1. 1/10th is just an economical limit for current practicality.
Second, we can at anytime have an actual breakthrough in several different fields that have hinted at FTL. Maybe that will happen, maybe it won't. But it was "impossible" for man to fly until the right mixture of knowledge and can-do came along back in 1903.
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04-07-2004 22:06
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