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Dissolving the Fermi Paradox

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Re: Dissolving the Fermi Paradox

#61

Post by titzer »

jessriedel wrote: post #56
true_religion wrote: post #49

Earlier quoted context omitted.

What does novelty have to do with dissolving the Fermi Paradox? Is Fermi is some well established science, with repeated experimental proof, upon which numerous other conjectures have been built on? Does it really require a novel approach to attack its basis?

The top-level commenter wrote > Everyone considered this option. From the very first day the paradox was posed. We don't know the parameters well, it's within our margin of error that no one else is out there, so it's an option. And the person I replied to was rebutting this point (that the approach is obvious and considered long ago). It's fine to write review articles, or clean up old arguments and repackage them,…

I don't think they are claiming to have invented math on probability distributions and I didn't mean to suggest that that is what is novel about this paper. They used a different, more powerful technique to look at the math of the Fermi Paradox and came to a conclusion different than that following from the normal treatment of the Drake equation. That's a reasonable contribution, IMO.

Re: Dissolving the Fermi Paradox

#62

Post by jessriedel »

jerf wrote: post #22
mirimir wrote: post #16

Earlier quoted context omitted.

Agreed. This is just picking parameters consistent with no detection of extraterrestrial civilizations. The point of the Fermi paradox is that it's a stretch to assume such parameters. It's not prediction about extraterrestrial civilizations collapsing or whatever. It's just an alternative to consider. And perhaps a warning about shouting at the Universe. Although it's probably too late to fret too much about that.

The article is not about picking parameters. The article is one meta layer up from that; they examine the distribution of parameters. I can't guarantee this is novel paper in general, but it's not something I've seen treated this formally before. I mean, it roughly conforms to what I've been saying for a while, but I only worked the math very intuitively and in a manner that could have been flawed, so I get no credit…

> I can't guarantee this is novel paper in general, but it's not something I've seen treated this formally before

Yea, I'd be very happy if they just said "here we make formal the possibility, considered since the paradox was first proposed, that there is enough uncertainty in each parameter that seeing zero ETI is perfectly compatible with expectations". That would have been a modest but useful contribution to the lit that would have informed further research. The issue I have is with claims that they are "dissolving" anything.

Re: Dissolving the Fermi Paradox

#63

Post by jcranmer »

jandrese wrote: post #46
jpm_sd wrote: post #2

TL;DR - It's not a paradox, because we're probably alone. Kind of a letdown!

The Drake equation is the epitome of garbage in garbage out. Trying to draw a line using a single data point. There was recent news from NASA about the discovery of organic molecules on Mars and the possibility of life there at some point in the past. Discovery that life once existed on Mars would blow up the assumptions in the Drake equation. As for the Fermi paradox I'm still of the opinion that its solution is sim…

Only two variables of the Drake equation can be meaningfully estimated: rate of star formation and fraction of stars with planets. The number of life-supporting planets per star is surprisingly ill-defined (what number is that for Sol?). All of the other variables are basically knobs that let you control what you want the answer to be.

> There was recent news from NASA about the discovery of organic molecules on Mars and the possibility of life there at some point in the past.

It should be pointed out that the organic molecules in question are known to be created by abiotic processes.

> As for the Fermi paradox I'm still of the opinion that its solution is simple but depressing: Interstellar travel is so difficult that by the time you're capable of it you don't need it anymore, and even when you're capable of it you still don't get very far outside of your stellar neighborhood.

Well, there's an even more depressing possibility: interstellar communication itself is effectively impossible, let alone travel. Any beam will spread out over a larger and larger radius, so even the most focused laser beams will become too weak to detect within I think a few hundred light years, so we're not even talking about trying to find aliens in the galaxy, we're talking about trying to find aliens in the nearest stars.

Re: Dissolving the Fermi Paradox

#64

Post by jessriedel »

titzer wrote: post #61
jessriedel wrote: post #56

Earlier quoted context omitted.

The top-level commenter wrote > Everyone considered this option. From the very first day the paradox was posed. We don't know the parameters well, it's within our margin of error that no one else is out there, so it's an option. And the person I replied to was rebutting this point (that the approach is obvious and considered long ago). It's fine to write review articles, or clean up old arguments and repackage them,…

I don't think they are claiming to have invented math on probability distributions and I didn't mean to suggest that that is what is novel about this paper. They used a different, more powerful technique to look at the math of the Fermi Paradox and came to a conclusion different than that following from the normal treatment of the Drake equation. That's a reasonable contribution, IMO.

But if you just formalize an approach that was considered by everyone right from the start, this isn't coming to a different conclusion. (https://news.ycombinator.com/item?id=17304389)

Re: Dissolving the Fermi Paradox

#65

Post by mirimir »

nervousvarun wrote: post #52
pbhjpbhj wrote: post #48

Earlier quoted context omitted.

Something I don't get, people say something along those lines -- that with earth-like conditions, blah-blah, earth-like planets, ... then life! But also experts claim life only arose once on Earth. So, in a place with perfect conditions, the perfect distance from the sun, the perfect atmosphere, perfect trigger, perfect environmental conditions, life only started once! Doesn't that make it so infinitesimally unlikely…

Just curious how can anyone conclusively claim life arose only once? Don't they just say we only have evidence that it arose once? Maybe it started twice or 100M times but 100% of those times the newly started life was "consumed" in some way by already existing life etc.

Yes, that seems a dubious claim. There's no way to know, except though simulations, how many dead ends there were. What we know is that all existing organisms share basic biochemical features. More or less the same nucleic acids, amino acids, and so on. So other paths arguably got competed out. Or merged, as we know for nuclei, mitochondria and chloroplasts in eukaryotes. Probably also components of bacteria. Flagella, maybe? The whole DNA/RNA/protein thing could well be a kludge.

The especially cool aspect of searching for life elsewhere in the solar system is the possibility that we'll find other variants that dominated.

Re: Dissolving the Fermi Paradox

#66

Post by squirrelicus »

TeMPOraL wrote: post #55
PaulHoule wrote: post #31

Ecosystems are limited by the availability of water, not sunlight. Also there are more "habitable" places in the universe which are underground oceans (the default condition outside the frost line) as opposed to a tiny fraction of rock worlds which have to parametrically fine tuned to have water -- ex. there are 10-20 worlds that have underground oceans in our own solar system. Why would a spacefaring civilization ca…

> The most absurd thing about "Battle: Los Angeles" is not that aliens would come to Los Angeles (as opposed to Detroit) to steal water, Hey, they landed near all major coastal cities; the movie was just following one group of soldiers fighting off one part of the invasion force. > but that they would come to a planet which has a thin layer on the surface as opposed to being just a run-of-the-mill dwarf planet or ast…

H2O isn't exactly rare in the universe, it's the third most common molecule after H2 and CO. Getting water into orbit is absurdly expensive compared to getting it from the other rocks with lower gravity and atmo, like Ceres.

Weird premise for a movie

Re: Dissolving the Fermi Paradox

#67

Post by bramgn »

ghaff wrote: post #21
adrianN wrote: post #15

Earlier quoted context omitted.

Von Neumann probes could probably colonize a good chunk of the Milky Way given a few hundred thousand years.

That in turn makes assumptions about the practicality of interstellar travel etc. But, yes. The counterpoint to space is big is that so are timescales.

This. I always wonder why discussions about the search for alien civilizations don't take the massive timescale more into consideration. Say you're watching a summary of our universe compressed to a hundred years. Each time a civilization pops up, it might just hold on long enough to last a nanosecond. We're just living that in that blip of a time.

Re: Dissolving the Fermi Paradox

#68

Post by jandrese »

jcranmer wrote: post #63
jandrese wrote: post #46

Earlier quoted context omitted.

The Drake equation is the epitome of garbage in garbage out. Trying to draw a line using a single data point. There was recent news from NASA about the discovery of organic molecules on Mars and the possibility of life there at some point in the past. Discovery that life once existed on Mars would blow up the assumptions in the Drake equation. As for the Fermi paradox I'm still of the opinion that its solution is sim…

Only two variables of the Drake equation can be meaningfully estimated: rate of star formation and fraction of stars with planets. The number of life-supporting planets per star is surprisingly ill-defined (what number is that for Sol?). All of the other variables are basically knobs that let you control what you want the answer to be. > There was recent news from NASA about the discovery of organic molecules on Mars…

It doesn't help that we have a giant noise source in the middle of our solar system that shoots the noise floor through the roof when you're trying to detect laser comms over light years.

Plus, even at lightspeed you're talking multi-year roundtrips to our nearest interstellar neighbors.

Our entire history of radio emissions has only made it to around 500 solar systems currently. Even if someone was listening and responded immediately the response probably wouldn't have made it back to Earth yet.

Re: Dissolving the Fermi Paradox

#69

Post by PaulHoule »

squirrelicus wrote: post #66
TeMPOraL wrote: post #55

Earlier quoted context omitted.

> The most absurd thing about "Battle: Los Angeles" is not that aliens would come to Los Angeles (as opposed to Detroit) to steal water, Hey, they landed near all major coastal cities; the movie was just following one group of soldiers fighting off one part of the invasion force. > but that they would come to a planet which has a thin layer on the surface as opposed to being just a run-of-the-mill dwarf planet or ast…

H2O isn't exactly rare in the universe, it's the third most common molecule after H2 and CO. Getting water into orbit is absurdly expensive compared to getting it from the other rocks with lower gravity and atmo, like Ceres. Weird premise for a movie

Exactly, H2O is rare on rocky planets. It makes more sense to mine it from Pluto.

Re: Dissolving the Fermi Paradox

#70

Post by gwern »

jessriedel wrote: post #60
gwern wrote: post #44

Earlier quoted context omitted.

Can you point to a single person making the point previously that even small amounts of uncertainty in the distribution of each variable in the Drake equation often implies a small or near-zero number of ETI even when the best mean point-estimate of the distribution for each variable, when multiplied together, predicts a large mean number of ETIs ?

I don't understand. Your point ("even small amounts of uncertainty ... a large mean number of ETIs?") sounds just like a rephrasing of his ("We don't know the parameters well, it's within our margin of error that no one else is out there"). In particular, how could your statement be false while his be true?

His point, as suggested by the comments agreeing with him and the claims that it's 'obvious', is that the parameters could be small. The problem with that is the parameters look large. Adopting a distribution and calculating it out gives much broader predictive distributions. You can have all the parameters not be that small but small enough, combined with minimal uncertainty, that on many draws from the posteriors, you get underpopulated universes once all the uncertainty and probabilities are integrated. What he wants to take by theft from individual parameters, handwaving them away as being small and thus causing the paradox, can be obtained without any trickery for a wide range of parameter values and 'margin of error's simply by the nature of the pipeline process producing a wide range of final outputs. It's akin to confusing the confidence interval around a mean for the predictive interval.
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