Readers question carbon nanotube transistors and brain organoids

Chip off the old carbon block

Scientists built the first microprocessor that uses thousands of carbon nanotube transistors, Maria Temming reported in “A chip made with carbon nanotubes, not silicon, marks a computing milestone” (SN: 9/28/19, p. 7).

Reddit user SchwarzerKaffee asked about the environmental impact of producing carbon-based microprocessors versus standard silicon-based ones.

Making microelectronics from silicon “is very energy intensive,” says materials scientist Michael Arnold of the University of Wisconsin–Madison. But carbon nanotube microprocessors would also require many of the same components and take about as many steps to make as silicon ones, he says. “The energy consumption, water usage and by-products all associated with the fabrication of microprocessors likely will not be drastically different.”

Dishing on brain organoids

Brain organoids fired coordinated electrical signals similar to those seen in human babies’ brains, Laura Sanders reported in “Clumps