Drag the dial to turn the bird — brightness = singlet-yield signal at that heading
A photon strikes a cryptochrome protein and kicks two electrons into a spin-correlated radical pair. The two spins precess around the local magnetic field; how in-step they stay by the time the pair reacts decides whether the chemistry ends in a "singlet" or "triplet" product.
Drag the angle slider (or the compass dial) to change the angle between Earth's field and the molecule's fixed axis. The precession rates of the two spin arrows depend on that angle, which shifts the live singlet/triplet yield bars. Click "Absorb Photon" to sample one stochastic event at the current yield.
Field-angle slider, precession-speed slider, photon trigger, play/pause, and a draggable 360° bird's-eye compass dial.
This is believed to be a real sensing mechanism, not just a model: European robins lose their magnetic compass under radio-frequency noise that should only disturb a quantum spin process, not a classical iron particle.
Fire a photon into a cryptochrome protein, watch the two resulting radical-pair electron spins precess, and see how the angle between Earth's magnetic field and the molecule's fixed axis shifts the singlet-versus-triplet product yield — the quantum signal a migratory bird reads as a compass.
A cryptochrome molecule absorbs a photon and forms a spin-correlated radical pair. The two electron spins precess at slightly different rates depending on the magnetic field's angle relative to the molecular axis, so the odds of the pair ending up in a singlet or triplet chemical state — visualized as live yield bars — swing with that angle.
Drag the field-angle slider or the 360° compass dial to rotate a simulated bird's heading; click "Absorb Photon" to trigger one stochastic radical-pair event sampled from the current singlet/triplet odds; use the speed slider to slow or accelerate the precession animation.
This is believed to be a real sensing mechanism, not just a model: European robins lose their magnetic compass under weak radio-frequency noise that should only disturb a quantum spin process, not a classical iron-particle compass.