Satellites are exposing weak bridges in America and around the world

Satellites are giving scientists a powerful new way to watch over the worlds bridges. Using radar imaging, researchers can detect millimeter-scale movements that may signal early structural problems long before inspectors notice them. The study found many bridges-especially in North America-are aging and increasingly vulnerable, but satellite monitoring could sharply reduce the number classified as high-risk. The approach could be especially valuable in regions where traditional monitoring barel...