Over the past few years, the MICROSCOPE spacecraft performed precision experiments to test the difference between gravitational mass, which governs how strongly matter responds to gravity, and inertial mass, which is the measure of resistance to being pushed. Our modern theory of gravity, Einstein’s general theory of relativity, says these masses are equivalent, which is (among many other things) why your stomach sometimes goes whoopsy when you’re driving fast over the crest of a hill, or when an airplane hits a bit of turbulence. To accompany the announcement of the final MICROSCOPE results, the American Physical Society’s Physics Magazine commissioned a comic from me and artist Maki Naro.
The linked article is for SIAM News, the magazine for members of the Society for Industrial and Applied Mathematics (SIAM). However, even though the main audience for this magazine is professional mathematicians, I wrote it to be understandable even if you gloss over the math. And it involves the word “tortuosity”, which is just fun to say.
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For SIAM News:
A white blood cell slips through the gaps between other cells, stretching and bending as it goes. Though its movement strongly evokes that of a macroscopic creature—perhaps a rodent nosing its way through a maze—the cell is guided only by chemical signals and molecular forces. It has no need for a brain, not even the one in the human body that it shares.
Mathematical biologists have developed a number of models to understand self-organization both within and between cells. Leah Edelstein-Keshet of the University of British Columbia received SIAM’s prestigious 2022 John von Neumann Prize for her significant contributions to this field. Edelstein-Keshet has been a leader in mathematical biology research for several decades and also penned one of the earliest textbooks on the subject: Mathematical Models in Biology . She delivered the associated prize lecture at the hybrid 2022 SIAM Annual Meeting (AN22), which took place in Pittsburgh, Pa., this July.
“I started off by looking at the interesting patterns that cells make,” Edelstein-Keshet said. “Fibroblasts try to align in parallel patterns, and the question was, how do they form these parallel arrays? We developed some mathematical language to deal with that. And it turns out that there are a lot of related problems of units that line up in parallel arrays.”