The most dangerous weather around Earth does not come with clouds. It comes from the sun, which can hurl bursts of energy and charged particles into space hard enough to disrupt radio signals, damage satellites, distort GPS, and drive electrical currents into power grids on the ground. In May 2024, a major solar storm also knocked precision-guided farm equipment off course, slowing planting and harvesting and costing U.S. farmers an estimated $500 million. For decades, the main response has been prediction. Space weather forecasters watch the sun, estimate what is coming, and give satellite operators and utilities time to brace. Brian Walsh, a Boston University engineer, is asking whether Earth could do more than brace. His team has modeled a way to temporarily reinforce the planet’s magnetic defenses during a major storm, using a group of spacecraft that would release material into near-Earth space. In simulations, the concept cut the intensity of a powerful geomagnetic storm sharply, suggesting that a severe space weather event might one day be softened before it fully hits. A NASA …