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Exponential Economist Meets Finite Physicist (2012)

dothemath.ucsd.edu

131–140 of 174 posts

Re: Exponential Economist Meets Finite Physicist (2012)

#131
post #98

Earlier quoted context omitted.

That's the great thing about thermodynamics, you can determine bounds for a few magnitudes in a physical system ignoring all the details about its evolution. For instance you can't disrupt the 2nd law, so at some point it's actually true that it is impossible to mitigate overheating and you won't be able to improve Stefan-Boltzmann law (except for increasing our emissivity, at night I'd guess). You can try to play wi…

"Wavelength- and subwavelength-scale particles,[1] metamaterials,[2] and other nanostructures are not subject to ray-optical limits and may be designed to exceed the Stefan–Boltzmann law."

That's interesting - are they more efficient at getting rid of entropy ? (And what would be the new limits? If they only give, for instance, a single doubling worth, that won't buy us much more time...)

Re: Exponential Economist Meets Finite Physicist (2012)

#132
Ultimately, this is a problem of semantics. Physics describes one objective reality that interacts with billions of subjective realities. Economics describes how billions of subjective realities interact to form one objective reality.

The article has a few places where the physicist attempts to ascribe an intrinsic value to an item (say dessert types) independent of the supply and demand curves for that item. The whole concept of a demand curve is that everyone has their own value that they give to an item. The fact that some people do NOT value some particular lifestyle improvements does not affect econ in the slightest.

Re: Exponential Economist Meets Finite Physicist (2012)

#133

Earlier quoted context omitted.

Kolmogorov was about 90 years ago. Shannon, similar. Neither of their accomplishments will limit future accomplishments and understanding (except those bound slavishly to such frameworks [as good as they may be today in certain applications]) >Existential risks in fact. (E.g. reliance on a single source of energy without fallback.) Existential risks for oil companies investors or CSP investors?

Now, not to be rude but if you think we are going to break the laws of thermodynamics or other physics then you literally believe in supernatural forces. As in magic.

If you think meta materials violate laws of thermodynamics, impossible to exist "naturally" in the universe and our understanding of the physical laws that govern the universe are static throughout time, then I have a bridge to sell you.

Re: Exponential Economist Meets Finite Physicist (2012)

#134

> thermodynamic limits impose a cap to energy growth lest we cook ourselves .. I’m talking about radiating the spent energy into space Huh? This seems to be a critical premise for establishing a crisis, yet it's incoherent and essentially imaginary. Ok, some ways we use energy have poor thermal efficiency. Light bulbs are the classic example, but look at the improvement from incandescent bulbs to LED's. Most uses of…

Is that true?

My physics is admittedly not great. However I though a 100% efficient lightbulb generates just as much heat, but at the place where the photons land (walls, floor, etc) rather than at the bulb.

I think basically any time we use energy, whether by running current through a lightbulb it by respiration after eating food, it ultimately ends up as heat.

Re: Exponential Economist Meets Finite Physicist (2012)

#135
post #58

Earlier quoted context omitted.

Mars does look a lot closer in 2019 than it did in 2012. Back then it seemed like no real plan existed, except for one little company not a lot of folks believed in. Now we’ve got billionaires in a space race and suddenly it seems obvious that we’ll colonize space to some degree even in the next 100 years, likely with some aggressive growth. We’ve only recently come off the gloomy decades after Apollo where space exp…

Sure it seems closer now than before, but reaching Mars is still very very far, it's nothing like going down the road to the chemist, for example let's say that we want to pursue the current population growth but on Mars, that's an estimated 82 million new people per year (130 million if you count only births), using the Starship SpaceX is currently developing that would take 820000 launches per year or 2250 per day.…

Actually, a space elevator would help a lot here, but it's questionable when/if we will be able to build one...

Re: Exponential Economist Meets Finite Physicist (2012)

#136

I think the dismissal of space colonization over a period of 400 years is...unreasonable. We could move all production to Mars for example and only consume the shipped resources. Sure that’s one doubling right there, but we could continue this process.

You wouldn't be able to exponentially increase the shipped in/out resources for long.

And taking the VERY long view, and galactic civilizations, assuming current physics, you end up running into similar issues (except instead Earth it's ALL matter in reach converted into Nuclear Reactors + Dyson spheres), and further expansion running into speed of light limits.

Re: Exponential Economist Meets Finite Physicist (2012)

#137
Has anyone done the math to determine what fraction of global warming is just from the steady-state relationship between heat production and radiation into space, regardless of changes in albedo? Always been curious about that one.

i.e. In the same way that a computer runs hotter when consuming more wattage, how much has the Earth gotten hotter just because we are consuming more wattage lately?

Re: Exponential Economist Meets Finite Physicist (2012)

#138
post #11

Am I missing something, or hasn't energy per capita in the developed world already stopped growing? As well as population growth in rich societies?

Except it's the total energy that matters in this discussion of Earth limits, not the one per capita...

Re: Exponential Economist Meets Finite Physicist (2012)

#139

Earlier quoted context omitted.

"Wavelength- and subwavelength-scale particles,[1] metamaterials,[2] and other nanostructures are not subject to ray-optical limits and may be designed to exceed the Stefan–Boltzmann law."

That's interesting - are they more efficient at getting rid of entropy ? (And what would be the new limits? If they only give, for instance, a single doubling worth, that won't buy us much more time...)

This was my prof at the time who introduced me to this stuff he was working on[0], you can read more about his work on their site if you are interested.

[0] http://www.zia-lab.com/

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