Sunlight is a turbulent stream carrying inseparable pairs of droplets. That’s what quantum entanglement looks like: two particles are so connected that a fluctuation in one instantly resonates in the other. In the past, creating such pairs required a 'calm pool' — a perfectly tuned laser beam. But scientists took ordinary sunlight (the very light rushing toward us at the speed of light) and passed it through a splitting crystal, which, like a waterwheel, divided the stream into pairs of entangled particles.
Light sensors using photometry showed near-perfect synchrony. The classic test proposed by Bell and refined by Aspect and Zeilinger confirmed genuine quantum behavior — with no hint of classical trickery. The wild stream performs as well as the calm pool.
Surprise: all it takes is a drop from the stream — the Sun gives billions of times more light per second than all quantum networks would ever need. A Mars rover could entangle particles at sunset, no lasers required. This fits into the quantum picture of the world and promises cheap quantum communication.
Every second, the Sun radiates billions of times more light than needed to run all existing quantum networks.
Like in science fiction: a Martian colony might one day exchange entangled signals with Earth using nothing but daylight.