Light curve (flux vs time)
Transit timing O−C (min)
This 2D simulator reimagines the exomoon-detection mechanic as a flat orbital diagram: a planet circles a star while a moon of adjustable mass and distance circles the planet, and every time the planet crosses the star's face the resulting brightness dip is plotted live on a scrolling light curve. Because the moon's gravity tugs the planet back and forth around their shared barycenter, each transit lands slightly early or late compared to a perfectly periodic prediction — that timing offset, plotted transit-by-transit as O−C, is the real transit-timing-variation (TTV) technique astronomers use to infer a moon they can never see directly. Raise the moon's mass or widen its orbit to grow the wobble past the detection threshold, or switch the moon off to watch the timing snap back to a dead-straight line.