Blog: Do the Math

[cliffhanger]

http://physics.ucsd.edu/do-the-math/post-index/

Excellent blog concerning all things energy related. The author suggests that it's physically impossible to continue our historic growths of energy consumption and the economy without boiling all surface water on Earth. A lower consumerism/Mustachian way of living on a world-wide scale is the answer to a looming energy crisis.

[scottish]

I wish Prof Murphy was still adding to that blog...   I don't think he's the greatest at accounting for innovation, but he is excellent at applying fundamental laws of physics!

[Bob W]

Thanks for the link

[Reynold]

I wish Prof Murphy was still adding to that blog...   I don't think he's the greatest at accounting for innovation, but he is excellent at applying fundamental laws of physics!

While Murphy is good at applying fundamental laws of physics, physics (which I've taught) really only shines at modeling very simple things.  Even something "hard" like particle physics is easy enough to be fundamentally solvable, while if economies were fundamentally solvable the folks at Long Term Capital Management would be rich instead of having gone bust in 1998. 

I didn't have a chance to read all Professor Murphy's posts, but from what I can tell he doesn't account for the fact that every country in history which has become "developed" has been showing a negative population growth rate, apart from immigration.  Simple exponential extrapolation of total energy use, for example, may not apply in the case of declining population, depending on relative rates the economy and energy use could both grow per capita while falling in total. 

On a more "purely physics" note, he does a simple analysis of bringing asteroid resources back from space, and overestimates the energy cost of doing so by a factor of 10 (http://physics.ucsd.edu/do-the-math/2011/10/stranded-resources/ vs. http://link.springer.com/article/10.1007%2Fs10569-013-9495-6)  and underestimates available engines by a factor of about 2000 (see the ion thruster in the table in http://en.wikipedia.org/wiki/Specific_impulse compared to the chemical engine he discusses).  This gives me some cause for concern about his other extrapolations. 

For a counter view to Murphy, try Robert Zubrin's "Merchants of Despair: Radical Environmentalists, Criminal Pseudo-Scientists, and the Fatal Cult of Antihumanism".  While I don't agree with all of that either, it does rather effectively make the point that Malthus, who did one of the first analyses like Murphy back in 1798, has turned out to be wrong as he also ignored innovation.  His analysis was based on food production rather than energy, and according to that we should all be starving, instead of having the lowest percentage of people farming in history with the richest diet in history (average, per capita). 

[scottish]

That's an example of what I meant by innovation - as standard of living improves in countries, population growth decreases. 

But then you say he overestimates the energy cost with the asteroid?  is this the 10E13 kg asteroid example?    (I'm not a  Springer fan, so I found the article here instead:   http://arxiv.org/abs/1304.5082)   If I understood the jargon in this paper it's talking about specific asteroids which are in an orbit that would make it 'easy' to capture them.   Murphy is talking about a general 10E13kg asteroid (much larger than the ones mentioned in the paper) and not having helpful orbital mechanics.    Imo this is another example where Murphy doesn't account for innovation.  Instead of brute force, asteroid miners could go after the low hanging fruit.

Aren't ion thrusters the same thing again?  A better form of propulsion than chemical rockets?  Anyway, I think I agree with you on Prof Murphy's shortcomings.  Basic physics is very different from applied engineering.   Hey do you ever read Vaclav Smil?

[Mr Dumpster Stache]

I came across Do The Math a few months ago, and it kinda scared the shit out of me.

Regardless of the details, it seems obvious that perpetual growth, especially exponential growth, is impossible. Some major downgrading of expectations is inevitable at some point. Even if nothing "breaks," when world population stops growing (UN estimates 10 billion), "growth" will have to slow way down. Not sure how modern corporations are going to handle that.

[Bob W]

Of course what he fails to understand is the Observer Principal.   The future is already occurring in quintillions of manifestations.   If he wants to impact the future, past or present,  he simply needs to observe differently.  It is not a math problem but a problem of understanding how "reality" comes into existence. 

[scottish]

This observer principle?

In science, the term observer effect refers to changes that the act of observation will make on a phenomenon being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner.

What's that got to do with the world changing?   Are you suggesting that the 'Do the Math' blog is affecting the way the world is changing?

[Reynold]

But then you say he overestimates the energy cost with the asteroid?  is this the 10E13 kg asteroid example?    (I'm not a  Springer fan, so I found the article here instead:   http://arxiv.org/abs/1304.5082)   If I understood the jargon in this paper it's talking about specific asteroids which are in an orbit that would make it 'easy' to capture them.   Murphy is talking about a general 10E13kg asteroid (much larger than the ones mentioned in the paper) and not having helpful orbital mechanics.    Imo this is another example where Murphy doesn't account for innovation.  Instead of brute force, asteroid miners could go after the low hanging fruit.

Aren't ion thrusters the same thing again?  A better form of propulsion than chemical rockets?  Anyway, I think I agree with you on Prof Murphy's shortcomings.  Basic physics is very different from applied engineering.   Hey do you ever read Vaclav Smil?

Correct, Murphy makes "simplifying" assumptions with his asteroid capture post which turn out to give answers orders of magnitude off, because he doesn't look at the best solutions technically available.  Therefore I don't put as much stock in his energy calculations as I might otherwise, especially since that is a much more complex problem to solve than asteroid capture, which I was able to find better solutions for in about 5 minutes of Googling. 

I hadn't heard of Vaclav Smil, but just looked him up.  His books do look interesting, I'll have to check them out.  His views on renewable energy not taking a large role in our power supply in the near future look right, at least. 

[taekvideo]

http://physics.ucsd.edu/do-the-math/post-index/

Excellent blog concerning all things energy related. The author suggests that it's physically impossible to continue our historic growths of energy consumption and the economy without boiling all surface water on Earth. A lower consumerism/Mustachian way of living on a world-wide scale is the answer to a looming energy crisis.

That's not possible from renewable energy sources, they add no heat to the system.
Also the energy usage in the US is trending downwards after peaking in 2007.
Efficiency of just about everything is constantly increasing, generally long after usage rates hit their maximum.
Vehicles are gradually shifting to EV which is several times more efficient than their gas burning counterparts.
Every year Intel releases a new processor series with more computing power and less power consumption. Skylake which is due in a couple months is tested as being 60% more energy efficient than the Broadwell architecture which was released earlier this year.
Revolutionary innovations such as 3d printing have the potential to decrease energy consumption in manufacturing by orders of magnitude.
Combine these trends with the natural peaking and decline of population in developed nations, and I see energy scarcity concerns eventually becoming a thing of the past.

[Mississippi Mudstache]

It seems like you are a prime candidate to actually read the website. Practically all of your objections are analyzed and soundly refuted. Give it a read before you dismiss it out of hand.