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The Fermi Paradox

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Re: The Fermi Paradox

#131

Post by jawns »

jacquesm wrote: post #37
gpsx wrote: post #32

Earlier quoted context omitted.

That is a good point. I agree with you. And people do have suggestions as to how life can be more probable than naively expected. But this answers the question why there is life at all as opposed to why we don't see more of it. My bias is that life is highly improbable and that we will not find any other life in our universe. But I also think it is no miracle that we exist, as I will describe. Given that I am trying…

> My bias is that life is highly improbable and that we will not find any other life in our universe. It's probable enough for you to be writing this. The only options are 0, one and many. We can rule out '0'. That leaves us to decide whether the chances of us being the only one are larger than the chances that we are one of many. Obviously the second one has more chance of being true the one where there is only one.…

> Obviously the second one has more chance of being true the one where there is only one.

That is not at all obvious to me. You are essentially taking the odds of the odds of something. A statistician can correct me, but I don't think it works the same way as calculating the odds of something.

Like, it's not as if we have a roulette wheel where "1/10^24" is an option, "2/10^24" is an option, "3/10^24" is an option, etc. In that case, "many" outweighs "1," certainly.

But if the odds of abiogenesis are so unlikely that we happen to be the only life in the universe, it doesn't seem like those odds must necessarily be wrong simply because it's logically possible for them to be more or less likely than they are.

But even then, it's kind of a wash. For as much as it could be logically possible for the odds to be more likely than they are (which would allow abiogenesis to occur more frequently), it would also be logically possible for the odds to be less likely than they are.

Re: The Fermi Paradox

#132

Post by chatmasta »

thelollies wrote: post #82
thefreeman wrote: post #76

Earlier quoted context omitted.

that exact possibility was listed in the article.

That's funny! I read the article and then had that thought five minutes later and thought I'd come up with it. Thanks for pointing that out :)

I often wonder how many of my opinions derive from this same mistaken originality... Quite scary, actually.

Re: The Fermi Paradox

#133

Post by kowdermeister »

pilaf wrote: post #128
kowdermeister wrote: post #118

I'm a bit surprised nobody mentioned AI-s taking over as the Great Filter. I'm sure every technical civilization attempts to do that because it's very tempting to accelerate your intelligence by computation. I've also read an interesting article that why probably machine life is more abundant than biological: http://www.popularmechanics.com/how-to/blog/robot-universe-d...

If AIs were taking over left and right we'd still expect to see some kind of evidence of their existence. Since they'd only be replacing biological civilizations I don't think it would count as the Great Filter, not in the context of Fermi's Paradox at least, as you'd end up with roughly the same number of technologically capable civilizations after the filter.

We can't comprehend intelligence million times beyond us, so speculating about their intention is very wild. Who knows, maybe an universal law of super-intelligence is to keep a low profile.

Re: The Fermi Paradox

#134

Post by sooheon »

31reasons wrote: post #96
vorg wrote: post #90

Earlier quoted context omitted.

Making money is one measure of profitability, another is reducing risk, something businesses aren't good at measuring. If there's two star systems instead of one colonized and the risk of one star system being wiped out by catastrophe is 1 in 1 million, then the risk of 2 being wiped out is only 1 in a quadrillion. A similar logic is behind why some people want to colonize the Moon or Mars. And when something has bee…

I doubt any sane civilization wants to spread like cancer.

I agree. That intelligent (much more so than us) beings would find the idea of littering replicating machines literally across the universe appealing doesn't make sense to me.

Re: The Fermi Paradox

#135

Post by sooheon »

wavesum wrote: post #58

I think the biggest fallacy in this rationalization is when it is assumed that advanced civilizations would want to expand like yeast; consuming everything, building dyson spheres... Why would they want that much energy, and why extract it from the sun? Trying to picture myself as one of these superlifeforms, I think would like to have the sun visible... For sunbathing and sh ... plants to grow etc... Maybe they have…

I agree. Why the assumption the Type 3 capable civilisations will necessarily wish to metastasise across the entire universe? One would hope that civilisations' ideas of what constitutes fulfilling and worthwhile activity will evolve and improve along with their technology.

Re: The Fermi Paradox

#136

Post by marcosdumay »

maaku wrote: post #102
danieltillett wrote: post #56

Earlier quoted context omitted.

I actually posted about this very topic a few days ago here. Once you have von Neumann machines spreading they will take over each new star system pretty much as soon as they reach it. Assuming the von Neumann machines are small and are being powered by an energy source (i.e lasers) from their origin star system they will spread through the galaxy at close to the speed of light. This spread method creates an interest…

Another testable variation of this is the gravitational effect of voids. Voids[1]are regions of the universe devoid of visible matter (stars), as far as we can tell. These are predicted by the inflationary model as regions of low energy distribution in the early universe. But if we find a void that appears to have gravitational effects on its neighbors, what an astronomer might call "a concentration of dark matter",…

There are stuff out there normaly tough of as "concentrations of dark matter"[1], altought nobody is really sure. I never heard about a "half eaten" galaxy, but I'd guess you hypostesis keep them that way for a very short time, so this is not surprizing.

The biggest problem I have with this family of explanations is that, unless the aliens discovered how to revert the Second Rule of Thermodynamics, they must irradiate some low temperature wave. And we measure nearly every candidate nowadays. Unless they are extremely far away, the only thing that could escape us is some very narrow band that happens to be out of range of all current telescopes - and those are not the features of a good heat sink.

[1] http://en.wikipedia.org/wiki/Dark_galaxy

Re: The Fermi Paradox

#137

Post by fernly »

dennisgorelik wrote: post #68

How about the theory that we are the way super-civilization spreads? If physical space travel is extremely expensive (as it should be, considering the distance), then may be it is better to send a signal that would trigger creation of life (in our case on Earth). Then when Earth civilization is advanced enough, it would be able to receive complete boot sequence and then fully advanced alien civilization would be repl…

... or, how about the hypothesis that we were intended to be a seed package (a.k.a. "biological rootkit") but due to a bug in the programming, we failed to develop properly. Just a mistake playing itself out...

Re: The Fermi Paradox

#138

Post by marcosdumay »

darkmighty wrote: post #129
danieltillett wrote: post #56

Earlier quoted context omitted.

I actually posted about this very topic a few days ago here. Once you have von Neumann machines spreading they will take over each new star system pretty much as soon as they reach it. Assuming the von Neumann machines are small and are being powered by an energy source (i.e lasers) from their origin star system they will spread through the galaxy at close to the speed of light. This spread method creates an interest…

Interesting. Just a note: it probably wouldn't seem as if a chunk of the galaxies was removed; in fact, I believe the luminosity (after some settling time) of a start with a Dyson sphere or the like would emit about the same light a regular star does -- the difference would be the temperature. The apparent temperature of the star should increase(?) (i.e. it emits(?) higher entropy radiation): by simple energy conserv…

Highter entropy radiation has lower temperature. But yes, the energy must go somewhere, thus the total energy irradiated is the same. It just shifts into infrared or radio.

Re: The Fermi Paradox

#139

Post by marcosdumay »

rjsw wrote: post #121
DavidSJ wrote: post #28

Earlier quoted context omitted.

There is actually a pretty good explanation for it in my opinion, that it takes about this long since the big bang for life forms of our complexity to exist. (meaning our planet was seeded at some point with some primitive life forms that than continued on their evolutionary tracks towards this point in time). Interstellar seeding is not required to believe that complex life becomes possible at approximately the same…

Frequency of big meteorite impacts probably becomes less over time too.

That's an intra solar-system variable, it does not apply to a galaxy.

Re: The Fermi Paradox

#140

Post by fernly »

wavesum wrote: post #58

I think the biggest fallacy in this rationalization is when it is assumed that advanced civilizations would want to expand like yeast; consuming everything, building dyson spheres... Why would they want that much energy, and why extract it from the sun? Trying to picture myself as one of these superlifeforms, I think would like to have the sun visible... For sunbathing and sh ... plants to grow etc... Maybe they have…

The SUN is visible everywhere within a Dyson sphere; it's the STARS that you can't see any more. The idea isn't that a civilization wants to do this; the idea is that it needs that much energy to continue with whatever industrial or infrastructure processes it requires to support a very large population. Dyson reasoned, we need steadily increasing amounts of energy input to support what we are doing; if the trend continues, what's the limit? (Typical physicist question, no?) The limit is to harvest all the energy emitted from your star. The only way to do that is to build a spherical collector, so that every photon can be captured. Then where do you live? On the sphere's inner surface. Of what material could you build a stable sphere one AU in radius? Where would that bulk of material come from and how be processed and positioned? How would you provide gravity on its inner surface? We have no fucking idea -- but we are not a Type-whatever civilization.
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