This fundamental constant of nature remains the same even near a black hole
Even on a black hole’s turf, an essential constant of nature holds steady. According to standard physics, the fine-structure constant, which governs interactions of electrically charged particles, is the same everywhere in the universe. Some alternative theories, however, suggest that the constant might be different in certain locales, such as the extreme gravitational environment around a black hole. But when put to the test near the supermassive black hole at the center of the Milky Way, the number didn’t budge, physicists report in a paper accepted in Physical Review Letters. The fine-structure constant is one of an assortment of unchanging numbers found in physics formulas, such as the mass of an electron or the speed of light. It determines the strength with which electrically charged particles pull on one another. Scientists don’t know why it has the value it does — about 1/137. But its size seems crucial: If that number were much different, atoms wouldn’t form (SN: 11/2/16). Using experiments on Earth,...