Satoshi Village the blog of Daniel Himmelstein

Electromagnetic pulses and slime molds

Recently I listened to a great podcast on the threat posed by electromagnetic pulses (EMPs). EMPs are short bursts of energy that can fry electronics. Large scale EMPs can be triggered by solar flares or high altitude nuclear detonations. A hefty nuclear EMP could destroy unprotected electronic equipment within a thousand miles radius. The podcast motivated me recount my strange story involving EMPs and slime molds.

Arguing the unforeseen

The year was 2010. I was a junior at Cornell, where I was on the debate team. In policy debate, there is a single topic for the entire year. And this year the topic was nuclear weapons. The season was in full swing. My partner and I were preparing for the National Debate Tournament qualifiers.

We had qualified our sophomore year, but only by the skin of our teeth. We needed a single ballot in the final round of the qualifiers, but were paired against a seemingly invincible opponent from Harvard. After the debate, expecting defeat, we nervously waited for the last judge to cast his ballot. Minutes turned to hours. Finally, the judge marked his vote, folded the ballot, and handed it to an elderset guru of the activity to announce.

We did it! I jumped up to embrace my partner and accidentally kneed him in the balls.

Not wanting to repeat the suspense, we were preparing vigorously for this year’s qualifier. To catch the opponents off guard, we had to prepare a novel proposal — one that had not been debated by any of the thousands of teams nationwide that year.

I stumbled upon the topic of nuclear EMPs. Information was scant. Whether the major superpowers even considered high altitude detonation in their nuclear planning was poorly documented. My sources were fringe. I even had to order a book because no university libraries carried it. Nevertheless, we pieced together a proposal to ban high altitude nuclear explosions to reduce the likelihood of debilitating EMP warfare.

Believing your own arguments is not essential for debate. But picking winning arguments is. Policy debate assumes an environment of natural selection: throughout a season, the arguments that survive are likely the most veracious.

Nonetheless, in the midst of sensationalism designed to outweigh the opponent’s criticism, I sensed a certain truth to our argument. The EMP threat is real and our society is ill-prepared. Ironically, we lost the one and only debate where we deployed this argument.

Perhaps, finally posting the 130 page compilation of evidence we compiled for a single loss will provide some closure.

Meanwhile in the land of slime

The same semester, I came across a study on slime mold, presumably via Slashdot because I didn’t have Twitter yet. The study used a slime mold species, Physarum polycephalum, to create a blueprint of Tokyo’s railway system.

The slime mold was unlike any life form I had seen. In its vegetative state, called a plasmodium, the slime mold forms a gigantic single cell containing many nuclei. It moves by pulsating, generally in search of its preferred food source, Quaker Oats.

To reconstruct the Tokyo railway, researchers placed Quaker Oats in a petri dish corresponding to population centers. Since slime mold detests light, the researchers illuminated areas corresponding to geographic no-nos such as lakes and mountains. Originating downtown, the slime mold initially expanded throughout the petri dish. Then the slime mold retracted to form a tubular network connecting the food sources. When analyzed for efficiency, cost, and fault tolerance, these networks were often comparable or superior to the real deal.

The slime and EMP converge

During this period, my junior spring, I took the best course of my Cornell experience, networks. The final paper asked for an “exploration of a topic related to the course.” I proposed using slime mold networks to reconstruct the power grid after an EMP attack. Food sources would represent power plants. Slime mold would be tasked with reconnecting the power grid, but constrained by a light gradient representing the blast.

While the EMP had a short lived debate appearance, it did help me get an A in class.

The slime still slithers

In the second year of my PhD at UCSF, I was required to present at a journal club. A study using the same species of slime mold as before caught my interest. The study found that the plasmodium deposits a slime trail, which it exploits for spacial memory. In other words, when foraging for Quaker Oats, the slime mold preferentially explores untrotted areas. The slides from my presentation are below:

Now let me celebrate the completion of this blog post with a bottle of Avery’s Toxic Slime electric blue soda.