John C. Baez's Blog, page 51

Social Contagion Modeled on Random Networks

 

Check out the video of Daniel Cicala’s talk, the fourth in the Applied Category Theory Seminar here at U. C. Riverside. It was nicely edited by Paola Fernandez and uploaded by Joe Moeller.

Abstract. A social contagion may manifest as a cultural trend, a spreading opinion or idea or belief. In this talk, we explore a simple model of social contagion on a random network. We also look at the effect that network connectivity, edge distribution, and heterogeneity has on the diffusion of a co...

Complex Adaptive System Design (Part 9)

Here’s our latest paper for the Complex Adaptive System Composition and Design Environment project:

• John Baez, John Foley and Joe Moeller, Network models from Petri nets with catalysts.

Check it out! And please report typos, mistakes, or anything you have trouble understanding! I’m happy to answer questions here.

The idea

Petri nets are a widely studied formalism for describing collections of entities of different types, and how they turn into other entities. I’ve written a lot about them...

Algebraic Geometry

A more polished version of this article appeared on Nautilus on 2019 February 28. This version has some more material.

How I Learned to Stop Worrying and Love Algebraic Geometry

In my 50s, too old to become a real expert, I have finally fallen in love with algebraic geometry. As the name suggests, this is the study of geometry using algebra. Aroun 1637, Pierre Fermat and Rene Descartes laid the groundwork for this subject by taking a plane, mentally drawing a grid on it as we now do wi...

Metal-Organic Frameworks

I’ve been talking about new technologies for fighting climate change, with an emphasis on negative carbon emissions. Now let’s begin looking at one technology in more detail. This will take a few articles. I want to start with the basics.

A metal-organic framework or MOF is a molecular structure built from metal atoms and organic compounds. There are many kinds. They can be 3-dimensional, like this one made by scientists at CSIRO in Australia:

And they can be full of microscopic holes, g...

Breakthrough Institute on Climate Change

I found this article, apparently by Ted Nordhaus and Alex Trembath, to be quite thought-provoking. At times it sinks too deep into the moment’s politics for my taste, given that the issues it raises will probably be confronting us for the whole 21st century. But still, it raises big issues:

• Breakthrough Institute, Is climate change like diabetes or an asteroid?

The Breakthrough Insitute seeks “technological solutions to environmental challenges”, so that informs their opinions. Let me quote...

Negative Carbon Emissions

A carbon dioxide scrubber is any sort of gadget that removes carbon dioxide from the air. There are various ways such gadgets can work, and various things we can do with them. For example, they’re already being used to clean the air in submarines and human-occupied spacecraft. I want to talk about carbon dioxide scrubbers as a way to reduce carbon emissions from burning fossil fuels, and a specific technology for doing this. But I don’t want to talk about those things today.

Why not? It turns...

Problems with the Standard Model Higgs

Here is a conversation I had with Scott Aaronson. It started on his blog, in a discussion about ‘fine-tuning’. Some say the Standard Model of particle physics can’t be the whole story, because in this theory you need to fine-tune the fundamental constants to keep the Higgs mass from becoming huge. Others say this argument is invalid.

I tried to push the conversation toward the calculations actually underlie this argument. Then our conversation drifted into email and got more technical… and pe...

The Cost of Sucking

I’m talking about carbon dioxide scrubbers. This post will just be an extended quote from an excellent book, which is free online:

• David McKay, Sustainable Energy: Without the Hot Air.

It will help us begin to understand the economics. But some numbers may have changed since this was written! Also, the passage I’m quoting focuses on taking carbon dioxide out of the air. This not really what I’m researching now: I’m actually interested in removing carbon dioxide from the exhaust from coal-fi...

Climeworks

This article describes some recent work on ‘direct air capture’ of carbon dioxide—essentially, sucking it out of the air:

• Jon Gerntner, The tiny Swiss company that thinks it can help stop climate change, New York Times Magazine, 12 February 2019.

There’s a Swiss company called Climeworks that’s built machines that do this—shown in the picture above. So far they are using these machines for purposes other than reducing atmospheric CO2 concentrations: namely, making carbonated water for s...

Exploring New Technologies

I’ve got some good news! I’ve been hired by Bryan Johnson to help evaluate and explain the potential of various technologies to address the problem of climate change.

Johnson is an entrepreneur who sold his company Braintree for $800M and started the OS Fund in 2014, seeding it with $100M to invest in the hard sciences so that we can move closer towards becoming proficient system administrators of our planet: engineering atoms, molecules, organisms and complex systems. The fund has invested i...