Radar systems for weather have become so advanced that they can determine the shape of a 6-millimeter raindrop from more than 8 miles away. How, then, did multiple objects recently shot down by fighter jets seemingly escape public notice until the U.S. military dispatched these objects with missiles? It’s as simple as not finding what you’re not looking for. Weather scientists, government agencies and the military all have powerful radar systems to detect objects at a very granular level. But faced with an airspace filled with numerous objects and passing clutter, each radar operator — driven by their particular interests...