Saturday Citations: Yet another solution for universal expansion; computing with brain organoids

Chris Packham
staff contributor

Gaby Clark
scientific editor

Robert Egan
associate editor

This week, researchers reported the discovery of four Late Bronze Age stone megastructures likely used for trapping herds of wild animals. Âé¶¹ÒùÔºicists have proven that a central law of thermodynamics does not apply to atomic-scale objects that are linked via quantum correlation. And two Australian Ph.D. students coded a software solution for the James Webb Space Telescope's Aperture Masking Interferometer, which has been producing blurry images.
Additionally, researchers are networking tiny human brain organoids into a computing substrate; evolutionary biologists have proposed that environmental lead exposure may have influenced early human brain evolution; and physicists have provided a predictive model to explain accelerating universal expansion without dark matter:
Nutrient bath computing
1984: William Gibson changes the science fiction landscape with "Neuromancer," a heist novel centered on thieves who operate within a global information system in a world of massive inequality dominated by wealthy oligarchs. Besides coining the term "cyberspace," Gibson introduced mass market fiction readers to the concept of biochips based on living tissue, comprising an alternative, and potentially more powerful, computing substrate.
2025: In our present world of massive inequality dominated by wealthy oligarchs, scientists at Swiss startup FinalSpark that they engineered tiny organoids of human brain cells cultivated from stem cells and used them as a rudimentary computer. Attached electrodes give the scientists access to impulses within the network of organoids, and delivering a small electric current produces either a spike in activity, or no activity—the equivalent of digital ones and zeroes.
Although the technology is in an extremely nascent stage, the researchers are exploring the potential of future biocomputing. Among other advantages, neural cells are 1 million times more efficient than artificial neurons; given the power-hungry nature of pursuits like training large language models, highly efficient computing of one kind or another is likely to make inroads.
This toxic heavy metal influences brain evolution
Combining fossil geochemistry, brain organoid experiments and evolutionary genetics, an international research collaborative proposes that environmental lead exposure influenced the evolution of the brains of Homo sapiens. Although there is a widespread belief that lead exposure is a modern industrial phenomenon, environmental lead is not uncommon, and for ancient humans, foraging or growing plants in lead-contaminated soil would have comprised a threat to health—and, the researchers argue, potentially shaped evolution.
Using a human brain organoid, they compared the effects of lead on two versions of a developmental gene known to orchestrate gene expression upon lead exposure during neurodevelopment. The modern human version of this gene is different from the Neanderthal version; the researchers found that the Neanderthal version showed disruptions in the cortex and thalamus that did not occur in the modern human version.
Using laser-ablation geochemistry, the researchers found distinctive "lead bands" in Neanderthal teeth that reveal episodes of lead intake from environmental sources. Renaud Joannes-Boyau of Southern Cross University says, "Our data show that lead exposure wasn't just a product of the Industrial Revolution—it was part of our evolutionary landscape. This means that the brains of our ancestors developed under the influence of a potent toxic metal, which may have shaped their social behavior and cognitive abilities over millennia."
Universal expansion explained, astronomy solved, physicists revise résumés
The universe: Why is its expansion accelerating? We'd all like to know the answer to that question, and if you could take all the dark matter out of the equation, it would be a lot easier. Researchers in Bremen and Romania, frustrated by the necessity of applying a mysterious "dark energy term" to the Friedman equations in order to produce a solution that matches the observed universe, took a new approach.
The Finsler model of gravity, an extension of general relativity, allows more accurate modeling of the gravitational force of gases. When they incorporated the Finsler extension into the Friedman equations, they predicted accelerated expansion of the universe in a vacuum without even once referring to dark matter. Is it a shortcut? Is it an accurate model that eliminates dark matter from the universe? Is physics finally solved forever? We report—you decide.
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