Light from the Big Bang is not just a ray. Its wave oscillates in a plane, like a trembling ribbon stretched across the universe. Usually, this ribbon doesn’t change direction over billions of years of travel. But ACT data showed: the polarization plane of the cosmic microwave background has rotated by 0.2 degrees — as if an unseen wind twisted it.

The culprit could be dark matter or dark energy — mysterious entities that make up almost the entire cosmos yet emit no light. Their fields, according to the hypothesis, can slowly rotate light. A similar twist was earlier spotted by WMAP and Planck satellites, strengthening the suspicion.

The effect lies outside the Standard Model — our best description of the microworld. Scientists are cautious: measurements have noise. But three independent instruments see the same thing. If confirmed, we’ll touch the invisible foundation of the cosmos for the first time.