Asteroid Impact Risk: B-Plane Keyhole Analysis

Planetary-defense teams don't track a single predicted path for a hazardous asteroid — they track a whole cloud of orbit solutions consistent with the observations, projected onto the b-plane at the moment of closest approach. This simulator generates that cloud as a real 2D-Gaussian "line of variations", lets you shrink it by lengthening the observation arc, and places a small gravitational keyhole nearby — a patch of the b-plane so narrow that only a tiny slice of the uncertainty cloud passing through it would set up a resonant return and a possible future impact, the same logic used to rule Apophis's 2029 keyhole in and back out. Adjust the approach speed to see Earth's gravitationally focused capture disc grow or shrink, and watch the live analytical and Monte-Carlo probability readouts track how a wider observation arc collapses the risk toward zero.