We’re used to LoRa as a free-to-use digital radio protocol allowing not-very-high data rate communications over distances of a few miles. It’s made all kinds of distributed sensor systems a breeze, ...

If you shine a light at a mirror, the beam is reflected inward to a central focal point, bouncing back toward you in a predictable manner—it’s a simple reflection of light, a spatial inversion. When a ...

IN the discussion which followed Prof. Lippmann's splendidly interesting communication to the Royal Society (April 23), on colour photography, I suggested the possibility of applying his method to the ...