There's an ancient light drifting across the universe that might just undermine particle physics as we know it, Science Alert reports. Scientists analyzing the cosmic microwave background—a faint remnant of the Big Bang—say they've spotted a twist in its light that could force a rethink beyond the so-called Standard Model. In their study, Yuto Minami and Eiichiro Komatsu discovered a polarization angle in the CMB, suggesting that its light is scattered, something like particles and water polarizing light into a rainbow. These twists of light could be dark matter or dark energy interacting with the CMB. And that interaction would violate something called parity symmetry.
The Standard Model says we should be able to flip the universe like a mirror, and the laws of physics would stay the same. Until now, there's just one fundamental interaction that violates parity symmetry, so if this is another, physicists might need a whole new model. Taking it further, Davide Castelvecchi writes in Nature that the light-twisting could be caused by a theoretical, mysterious force dubbed "quintessence" that behaves differently from dark energy as it accelerates the universe. "If quintessence does pan out as an explanation, it will have cascading effects" on how we estimate the universe's age and understand its expansion, he writes. But scientists are responding with caution thus far. "If it were real, it's big," says one. (Read more physics stories.)