James

The Emergent Multiverse — David Wallace

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“When you come to a fork in the road, you should take it”

So goes the jocular advice of Yogi Berra.

But what if this is what the universe actually does? What if we live in a garden of forking paths, of events that can go one way or another and in fact do both?

This is the subject of today’s podcast with David Wallace. David holds the Mellon Chair in Philosophy of Science at the University of Pittsburgh. He is one of the leading advocates of the Everett interpretation of quantum mechanics.

Originally proposed in 1957 by Hugh Everett and also called the Many Worlds Interpretation it offers a way of unpacking the precise mathematical predictions of this theory. 

The issue is this: quantum mechanics permits small things — atoms, electrons, photons — to be in frankly weird states. A single particle can be in many places at once, or traveling at many different speeds. 

These superpositions are key to Quantum Mechanics. Integral to this theory which explains how stars work, has enabled us to build computer chips and, indeed, lies at the very foundations of our understanding of matter — the uninspiringly named “Standard Model” is a quantum mechanical theory. 

Perhaps you have no issue with these tiny particles being in such weird states — you can’t see them. But quantum mechanics does not draw a qualitative distinction between small and big things. Like the rest of physics, it treats big things as agglomerations of small ones, the difference between them is of quantity, not kind. So quantum mechanics appears to tell us that big things like people, or (famously) cats can be in multiple places at once or even in seemingly contradictory states of being dead and alive. This is not what we observe.

The original attempt to explain this away was to say that when a measurement takes place these superpositions break down and crystallise into a single state. You might have come across phrases like “the collapse of the wavefunction” to describe this idea that things go from being spread out, or wavelike, to being localised. But what’s so special about measurement that it should provoke such a change of behaviour, what even is measurement if not just another physical process?

Other attempts propose modifying quantum mechanics — adding a new mechanism that would cause the crystallisation or collapse that doesn’t privilege measurement. However, it is no mean feat to try to modify a theory that has had such predictive success.

But what if we do not try to explain anything away?

What if we take seriously this idea of superpositions at all levels, not just the microscopic but all the way up to human and even universal scale?

Does quantum mechanics tell us we will observe something being in two states at once? No. Hugh Everett, David Wallace, and many others reason that quantum mechanics tells us that the world branches and that as the small superpositions become large those large ones represent worlds and each world looks much like the world we inhabit — where objects are one thing or another but never both at once.

When a photon can follow two different paths, it does, when the detection apparatus can observe it in two different places it will, when I can see that apparatus registering two different things, I will. But there is one me, and another me and neither sees anything extraordinary. The world has followed the fork in the road.

This is a theory with almost incredible consequences. But it has unassuming origins. It does not assume that there is anything special about measurement nor that quantum mechanics is incomplete. It is a radical theory for it goes to the roots of quantum mechanics, from these the branches emerge.

David was my tutor when I studied Physics and Philosophy as an undergraduate at Oxford, my thanks to him for giving his time to my curiosity once again.

References

The Yogi Berra line is one Harvey Brown used in his lectures on MWI.

Mining the Air — Casey Handmer

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Hydrocarbons are not bad. Over the last three hundred years they have propelled global growth and technology. Steel, trains, planes, plastics, and processors owe a historical debt to the energy that we have readily extracted from coal, oil and gas. 

The way we get hydrocarbons is bad. In taking them from the ground and burning them we transport carbon from the crust to the air. The deleterious consequences of this on our climate are well known. Furthermore, the inhomogeneity in their distribution has led to global iniquities, indeed reserves of such natural resources continue to prop up unsavory regimes, even eliciting deference from other powers that profess to uphold more democratic principles.

Casey Handmer, founder and CEO of Terraform Industries (TI) joined me on the inaugural episode of the Multiverses podcast. He has a plan to create a cleaner, fairer hydrocarbon economy:

  • Extract hydrocarbons from the air. Keeping the atmospheric balance intact — even improving it. 
  • Make this work almost 
  • everywhere. By relying on more equitably distributed resources: sunshine and air 
  • Do this more cheaply than drilling. 

Casey has Ph.D. in theoretical astrophysics and has worked at NASA’s JPL and at Hyperloop One. 

The technology behind the plan is old: scrub carbon from the air (like plants!), use water to create Hydrogen (electrolysis — discovered ~1800), combine the hydrogen and carbon using the Sabatier process (discovered ~1900) to produce methane. Methane, or natural gas, is the gateway hydrocarbon — CH4 — easy to transport and can be used as the basis for more complex synthetic fuels.

The economics that makes this work is new. It requires copious, low-cost energy from solar PV for this process to undercut crust-mined methane. That energy is used to turn the fans that churn through the air, electrolyse the water and run the Sabatier process. Using projections of solar energy costs, Casey estimates that in the mid-2030s it will be cheaper in most inhabited places to generate hydrocarbons this way than by drilling.

Because TI is confident that solar power will continue to fall, its efforts are focused on building something that can quickly get mass adoption — that means building cheap machines rather than ones using expensive components that could operate at higher efficiency. When PV is super cheap, we can be wasteful of it if it means a faster transition to net zero. We don’t need highly efficient processes to create fuels, we just need a lot of solar. 

If the TI thesis plays out, it will enable a phase change in solar adoption. In many cases it does not currently make sense to connect more solar to grids — it only adds to generation at hours that are already well covered. More storage solutions and HVDC to move energy between time zones will change that. Even then, it’s hard to connect new solar farms — it can require years of permits to get the grid interconnections laid. If it becomes cheaper to produce methane from the air then the grid constraints are bypassed, a solar farm can be constructed anywhere with access for trucks and the methane produced can be stored in the mundane ways (tanks).

I hope it happens.

Questions I’d ask if I had this conversation again

Is there a floor to solar costs?  A couple of reasons to think there might be:

  • It uses up some natural resources and the cost of these has floor. Does plywood installation display a learning rate? Perhaps slightly, but it’s masked by resource costs.
  • Solar needs land area, another constrained resource. 

What about air-to-food? Startups like solar foods are following a similar model in turning energy from the sun into hydrocarbons. Could there be any advantages to colocating facilities for food an methane production? Will the prices of food and fuel equalize in terms of $ per joule? The cheapest food is currently about 18MJ Joule per dollar (see https://efficiencyiseverything.com/calorie-per-dollar-list/) whereas gasoline is more like 60MJ per dollar — so it’s about three times as cheap. Will food become relatively cheap compared to gas? Even with gas coming down in price. More good news?!

Update — Casey got back to me by email with some comments on these:

  • Cost floor: Might get as low as $30k/MW. Land cost becomes important at that level without severe regulatory assistance! [JR: for ref, the turnkey installed cost is $900k per MW at the low end currently — so the floor is a long way down]
  • Air-to-food: Food is actually about 100x more expensive than gasoline per usable unit of mechanical energy. Probably better to collocate synthetic food factories (if any) with centers of demand, as food is less transportable than natural gas through existing natural gas pipelines!

References:

https://terraformindustries.com/

https://caseyhandmer.wordpress.com/

https://www.researchgate.net/publication/363529984_Empirically_grounded_technology_forecasts_and_the_energy_transition — Rupert Way et al on why renewable costs will continue to come down (the “learning rate”) 

https://www.economist.com/technology-quarterly/2023/04/05/adding-capacity-to-the-electricity-grid-is-not-a-simple-task Technology Quarterly from The Economist (paywall) on electricity grids

Do not disturb

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Do not disturb

On my phone there is a button: do not disturb.

So I press it. 

Yet immediately my son comes to prod me and inform me of an immediate requirement of ice cream, then bursts into incredulous tears when I explain there is none left, that he himself ate the last morsel the previous evenings when we had resorted to luring him into the bath with said treat. He saw the empty punnet with his own tearful eyes.

I suppose there is a problem with my phone. Either that or my son, but he is more or less perfect. 

Perhaps a software update will fix it.

Vessel, Cargo, Atom, Planet

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Vessel, Cargo, Atom, Planet

These words came in longships and in barques, they were dragged over logs, carted among wines, olives, and figs, bundled up and slung across the backs of soldiers and cradled by the hands of children. 

These words carry the atoms which fled Democritus’ lungs and the photons that lit the visions of Horace. Within their inflection, there is the curve of a bison’s flank, the curve of the walls of the earth.

These words were quarried in Istria, felled in Palearctic forests, picked from Lydian vines, and harvested from wheatfields that drink from the Elbe.

 Sometimes a sword is unearthed. Half consumed by the mud, its blade rusted away, of no use in any hand. Still, it is proudly displayed, its survival is seen as a thing of wonder.

Yet the words that traveled with that sword and spilled out of its scabbard retain the power to cut creation into the smallest pieces. 

To be carried, to carry, to dismantle, to compose.

What are you thinking of right now?

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Or, a sketch of a proof of the infinity of thought

No worries of rain. Only an idea, a notion, or even less, a word. The beginnings of a word. Something that is not yet, yet is, is a thing, but not a thing that is. This sort of thing. The sort of this that does not have a word, no name, there are words around it, but none of those words are its name. And without a name, we do not yet know its character, and a name will change its character. If we name it, we destroy it. We fill the space between the words, and that space is its body.

No worries of rain. No images of oceans or what is within oceans. Nothing that is liquid or solid or gas or plasma is what I am thinking of right now. Neither animal, vegetable, nor mineral. No real pattern. What I am thinking of is at an angle to all these things and to every item in every lexicon. Orthogonal, or — better — diagonal.

And if you should think of some new thing that is none of the things of which I am not thinking, I can tell you already, I am not thinking of that either, it is equally oblique to and untouched by that.

That’s what I’m thinking of right now. 

I trust that makes things clear.