A confounding factor for the Drake Equation

[elfs]

I can't help but wonder if there's a factor missing from The Drake Equation, or if not a factor, at the very least a multiplier that makes the f_c (fraction of civilizations that actually go on to release detectable signals) factor far smaller than anyone might anticipate.

The Drake Equation is a mathematical formula for "the number of civilizations that might arise in our galaxy with which communication might be possible." Arguments have risen over how each factor should be calculated: the rate of star formation, the average number of planets that can support life, the fraction that develop life, those that go on to be intelligent, and those that might release signals, and how long those civilizations might persist, for examples.

I've proposed in the past that the "signals/duration" part of the equation needs to be rethought: as we shift to ever more esoteric means of exploiting bandwidth, our detectable signals evolve into "noise" for anyone except ourselves, as we have the codecs necessary. It becomes even more noisy and less intelligible as coding/decoding becomes inextricably bound to cryptography and authentication.

But one other issue that's recently come to mind is this: the persistence of a civilization that can release useful signals is directly related to the availability of a local, easily exploited source of high-density energy.

For millions of years, our planet has banked somewhere between two and ten yottajoules (I enjoyed calculating that we used approximately 11.5 zettajoules of energy last year) of absorbed and produced energy in the form of oil and other natural gas sources. We have a pretty narrow window in which to bootstrap ourself into a post-petroleum civilization, and we've been very lucky to have that much easily exploitable energy at hand. We can only hope that our civilization gets its act together and achieves a post-petroluem existence without falling backward economically, with all the pain and terror that would ensue if we did.

I can't help but assume that the f_c is much, much smaller than previously thought; it's not just about reaching civilization and not blowing yourselves up: it's about having resources that let you get post-agricultural at all.

Comments

[mikstera.livejournal.com]

I, too, have thought that technological civilizations would use increasingly efficient means of communication, meaning less energy leaked out to space, and signals compressed to the point they look like noise.

Not a good recipe for detectability.

The size of the window during which people have access to easy sources of high-density energy, and easily accessible non-renewable resources are also going to be limited.

Another factor... how many civilizations end up going the way of, say, uploaded polities a la Greg Egan, or Matrioshka brains a la Stross.

In short, non-expansionist civilizations content to stay in one solar system, expanding neither physically nor electromagnetically.

Sadly, we don't know if FTL travel is physically possible.

Things aren't looking good for a United Federation of Planets... much as I would wish otherwise.

[tcepsa.livejournal.com]

I agree that as means of communication become more efficient it would be increasingly difficult for another civilization to detect them as communication. However, this also assumes (as I believe you alluded to) that they are not interested in finding other civilizations out there. If I'm not mistaken, the SETI program (or something along those lines) is deliberately transmitting a signal with a relatively straightforward encoding based on our own scientific and mathematical discoveries (which we believe would be the same on other planets). I think it's something to do with hydrogen or carbon and possibly with prime numbers (though I may be getting that confused with the movie Contact ~wry grin~)

Anyway, my point is that even as a civilization becomes more sophisticated in their communications, it does not mean that all of the radiation from their planet would necessarily become comparably indistinguishable from noise if they deliberately continued to broadcast a signal that was designed to be detected by other civilizations and if they were able to find a way to maintain power to it.

(PS I love your A Miracle of Science icon ^_^)

[mikstera.livejournal.com]

There have been some attempts at transmitting signals from Arecibo, but no, SETI is strictly a signal receiving and processing project.

We could pick up a deliberate broadcast... if it were being broadcast in a band we were monitoring, and was a signal we could differentiate from the background. The fact that we haven't (and haven't received any visitors) is the "Great Silence" that has us all puzzled.

Yes, my love for A Miracle of Science knows no bounds... my next desktop computer (a quad core, SLI'd, water-cooled beast) will be named "Caprice". :)

[xengar.livejournal.com]

I thought that we knew that FTL travel was possible, just that all the methods so far envisioned require absurd amounts of exotic materials. I thought we had managed two or three of the sort of thing that can be demonstrated in the lab on a single atom or molecule, but is practically impossible for moving any meaningful amount of mass any useful distance. So we aren't so much in the range of "can we move things faster than light" but in the how do we do this without requiring an amount of negative mass mater capable of balancing out Saturn to propel a single person craft."

In more positive news, and more directly related to Elf's post, I'm excited about this news (http://www.physorg.com/news136738014.html). Ignoring all the hyperbole and wild speculation in the article, a way to efficiently generate hydrogen and oxygen from ordinary tap water is a huge step forward in energy storage.

[jordan179.livejournal.com]

Another factor... how many civilizations end up going the way of, say, uploaded polities a la Greg Egan, or Matrioshka brains a la Stross.

In short, non-expansionist civilizations content to stay in one solar system, expanding neither physically nor electromagnetically.

I've never grasped why uploaded people would, by virtue of their uploading, lose all interest in interstellar expansion. I can see why they would lose some of that interest, but the other effect of being able to compress people into computer programs is that something the size of Voyager could be a vast starship with hundreds of crew onboard.

[mikstera.livejournal.com]

If you're living in a Matrioshka Brain (or even something smaller), you've got so much virtual space that there'd be a lot less incentive to put the energy, time, and risk into physical exploration.

[jordan179.livejournal.com]

If you're living in a Matrioshka Brain (or even something smaller), you've got so much virtual space that there'd be a lot less incentive to put the energy, time, and risk into physical exploration.

"A lot less," sure. But the energy, time and risk are also "a lot less" when you are a program running on a computer, can control your own perception of time by altering your clock rate, and are able to make backups and duplicates of your own personality. And you'd think that at least some of the uploaded people would recollect that their own long-term survival depends on extending their civilization's base of support out as wide as possible?

[tongodeon.livejournal.com]

There's another factor: metal. It tends to sink to the core of the earth. We've got a geologically active planet, which is unusual, and is the reason why we've got stuff like iron and copper. If we weren't living on a geologically active planet all the good stuff that we need to make transmitters would be buried thousands of miles below us.

[jordan179.livejournal.com]

There's another factor: metal. It tends to sink to the core of the earth. We've got a geologically active planet, which is unusual, and is the reason why we've got stuff like iron and copper. If we weren't living on a geologically active planet all the good stuff that we need to make transmitters would be buried thousands of miles below us.

To some extent, though notice that it doesn't appear to be on Luna or Mars, neither of which has experienced much geological activity in billions of years.

[athelstan.livejournal.com]

Stanisław Lem wrote about this in Fiasco. He has his own very interesting ideas about civilizations communicating in this very narrow window. It's worth the read and Lem is a deep thinker about this.

[jordan179.livejournal.com]

We don't have to worry about this because we have a lot of uranium and thorium in the Earth's crust, plenty to get us to nuclear fusion. Were you arguing that a lot of other planets might not have been as fortunate in their geological composition? I'll admit our civilization would be facing a dicey energy future if we didn't have both nuclear fission power technology and nice ample reserves of fissionables.

There's another more sinister issue here, though. The more fissionables you have, the easier it is to blow your civilization to bits, before you get nuclear fusion power (which among other things makes the other planets in your system more accessible). Maybe many civilizations who have enough uranium to avoid serious fossil fuel energy crises (not the little piddly thing we're experiencing now), have so much that they fall apart into nuclear warlordism?

[dsgood.livejournal.com]

It's possible to run internal combustion engines on wood-charcoal gas; it was done in Europe during WW II. Or on used French fry oil, as is being done to some extent now. Or on alcohol.

[norincraft.livejournal.com]

The Drake Equation always struck me as a 'back of the napkin' sort of idea. It seems to neglect that life could also spring up on a moon or might not be what we imagine it to be like. That is, that aliens might be truly alien and not just humanoid in mind but in a recognizable (or not) form.

In a passingly related way, I was looking at a horse a year or so ago. My darling was offering it a whole apple but it wouldn't eat it. But it would eat a carrot.

"No surprise there", I said, "long things are good; round things are suspicious."

I was half joking but, the horse would eat sections of apples happily, even small apples which it could easily eat.