Movies usually begin planetary defense with a launch countdown. Real life begins with a dot in an image, a timestamp, and a lot of careful math.
Survey telescopes scan the sky. The Minor Planet Center gathers observations from professionals and amateurs. NASA’s Center for Near-Earth Object Studies and ESA’s Near-Earth Object Coordination Centre calculate future paths and watch for anything worth extra attention.
YR4 put that network through a rare live exercise: teams found it, shared data, published changing probabilities, and aimed Webb at an extraordinarily faint target. The reward is a remarkably detailed forecast for a 60-meter object passing through the Earth–Moon system years from now. Planetary defense is less “space cowboys” and more “excellent global group project.”