Looking for Some Waist Heat

December 12, 2012 5:31 PM

A five-part series on the ultimate limit on technology, and how that limit could help us find other civilizations: 1 2 3 4 5 [via]
posted by cthuljew (16 comments total)

His math suggests that the likelihood of us being the only civilization in our galaxy, much less the universe, is so near zero that as far as I'm concerned the only reason why the universe looks "empty" to us is either 1) because we don't know how to look (and that is becoming less likely with each passing survey), and/or 2) because we're being deceived. Interesting times.

What do you think about chocolate-coated manhole covers?
posted by seanmpuckett at 5:58 PM on December 12, 2012 [2 favorites]

You know, I wish this stuff would come up in modern politics. I mean, Obama would call Boehner and say "we've got to have a balanced approach, and these Dyson spheres will cost a lot." And Boehner would say "conservation of energy says that all of the starlight plus all of the non-starlight energy must escape eventually as waste-heat. As conservatives, we're going to need some concession there." And Obama would be like, "I campaigned on the idea that Kardashev civilizations should quickly make the jump from type II's to type III's, so I'm sticking with that."

That would be so cool. Politicians would care about the future.

Instead we're worrying about something that will happen in a few weeks.
posted by twoleftfeet at 6:13 PM on December 12, 2012 [15 favorites]

....as far as I'm concerned the only reason why the universe looks "empty" to us is either 1) because we don't know how to look (and that is becoming less likely with each passing survey), and/or 2) because we're being deceived. Interesting times.

3) We can't see a significant fraction of the universe from here.
posted by DU at 6:23 PM on December 12, 2012

The "end" of technology is not a new discussion.
posted by absalom at 6:26 PM on December 12, 2012

I've become less and less convinced over time by these "exponentially multiplying monkeys" scenarios. They all seem to basically assume we/other species would forever live in some Werner von Braun future of giant spaceships full of breeding humans.

I'm not saying I'm such an optimist that we won't just kill ourselves, but it seems like if we don't, there's reason to think our technological progress might open up new paths. Remaining as poorly self-understood biological machines, culturally programmed towards an ever-expanding industrial civilization, actually does sound like a good recipe for collapse.
posted by crayz at 8:04 PM on December 12, 2012

"Keeping up with the Kardashevs." Hah
posted by SkinnerSan at 8:10 PM on December 12, 2012 [2 favorites]

I've become convinced that the second law of thermodynamics isn't the show-stopper it used to be. There are ways around it, as Maxwell pointed out when he brought up the idea of a daemon... there are ways to extract work from ambient heat, without having to dump it into a cold sink, slowly making their way through the labs, and eventually into use.

These will get us around the carnot limit, and we can do even more powerful things, in the future. 8)
posted by MikeWarot at 8:48 PM on December 12, 2012

None other than Richard Feynman gave an excellent and highly readable summary of the reasons Maxwell's Demon can't actually violate the second law, in his Lectures on Computation. The Leff & Rex book is good for an even deeper look at the topic.
posted by mbrubeck at 9:51 PM on December 12, 2012

There are ways around it, as Maxwell pointed out when he brought up the idea of a daemon
Remind me again, how much energy does this daemon take to run?
posted by sebastienbailard at 9:54 PM on December 12, 2012

What? No. Maxwell's Demon only appears at first blush to violate the Second Law. But that's because the thought experiment posits the existence of demons. That's where the violation occurs.
posted by Kadin2048 at 10:07 PM on December 12, 2012

Why we haven't encountered intelligent life:

Maybe they aren't starfaring. There's no reason why an intelligent life form should outstrip it's ecological balance. Curiiosity doesn't have to include interplanetary travel.

Maybe they don't listen to the radio--they may not have ears.

Maybe they don't have eyes, or the equivalent.

They may live underwater.

Nothing says sentient beings must survive. We haven't been around long enough to even try to make that claim for ourselves. It could be that any critter going the path of warfare and unchecked expansion is doomed to a short, violent existence.

Andromeda, for only one example, is over two hundred million light years away. Maybe they sent us a message the other day, but I won't hold my breath until it gets here. Wait, why would any being from Andromeda send us a message? Never mind. Not many of the stars in our own galaxy are within a few dozens of light years from here, so we have a few more years to go, before anyone in the neighborhood gets back to us about those I love Lucy shows.

Maybe intelligent life exists, but it doesn't resemble humans in funny suits, so we don't know what to look for. What if it's huge?--let's say that a single individual spans parsecs instead of inches, feet, meters. Our grasp of physics could be more primitive than even our physicists believe. We don't really know what flat space, curved space, or spacetime really means. We can't even really define time in any meaningful way. Intelligent beings may exist in dimensional folds that we aren't able to percieve. Maybe they notice us, but don't consider us as being able to percieve them in any meaningful way: looking at us through their lenses, we are simple little critters with no way to understand the vastnese of their universe.

Maybe they are out there, and they actually do resemble humans in funny suits--Andorians, let's say--and they were about send us a Tweet, but then Fox cancels Firefly. Their antennae quiver in disgust and they go elsewhere for companionship.

Maybe we are alone. We're it. Unique.

If I consider all these hypotheticals, the last one seems to hold the worst odds. Personally I'm going with the Andorian theory.
posted by mule98J at 10:52 PM on December 12, 2012 [4 favorites]

What? No. Maxwell's Demon only appears at first blush to violate the Second Law. But that's because the thought experiment posits the existence of demons. That's where the violation occurs.

If you did have a tiny Daemon, it would take energy to run his little flashlight, photosensor, brain, and tiny wooden gate a few atoms wide.

The Leff & Rex book looks fun.
posted by sebastienbailard at 12:17 AM on December 13, 2012

IIRC It turns out that the computational cost of making the decision about whether to open the gate or not on a per atom basis for a putative Maxwell's Daemon exceeds the energy gained by partitioning the the gas into hot and cold chambers. One of Maxwell's Daemons would need a cost-free Oracle in order to come out ahead, even if they existed.
posted by pharm at 3:56 AM on December 13, 2012

Our civilization as a whole gives off 500 exajoules of waste heat every year -- 0.01% more than the planet would if we were not here

Wow. Looks like a great series, but I had to stop just to ruminate those numbers. "Waste" is a fairly subjective adjective (were the pyramids or Burj Dubai or Jerry Lewis telethons etc. "waste"?) but getting past that ... all our efforts generate 1/10,000 more waste than the planet does without us?

Looking forward to the rest!
posted by Twang at 5:56 AM on December 13, 2012

In the case of all those, the waste heat is the heat that came off the bodies of the Egyptian farmers as they hauled stones, the crane and tractor engines as they lifted earth and beams, and the cathode ray tube or whatever it is in a television that gets warm. All machines converts usable energy into some (small) percentage useful output, and the rest into the machine getting warmer than it was before. It is not practical in the vast majority of cases to recapture this heat, because it is too low and too far away from a power station to actually contribute to any more energy generation.
posted by cthuljew at 6:54 AM on December 13, 2012

I just came here for the chocolate covered manhole covers.
posted by fnerg at 12:26 PM on December 13, 2012 [2 favorites]