When you buy through links on our articles, Future and its syndication partners may earn a commission.Arc-like shock waves travel outwards during a galaxy cluster merger, converting an enormous amount of energy into heat. The left image shows the gas density and the right image shows the dissipated energy with clearly visible shock fronts. | Credit: AIP/J. WhittinghamAt the universe’s grandest scales, galaxy clusters collide in slow-motion cataclysms, leaving behind immense, ghostly arcs — vast ribbons of diffuse radio emissions that can stretch across millions of light-years. Forged by gigantic shock waves that accelerate electrons to near-light speed, these strange structures are known as “radio relics.”Astronomers have cataloged dozens of them, yet their behavior has remained remarkably difficult to explain.AdvertisementAdvertisementAdvertisementAdvertisementObservations from NASA’s Chandra X-ray Observatory, Europe’s XMM-Newton, and other telescopes have for instance revealed magnetic fields threading the relics that are far stronger than our models predicted. The shock waves of these relics also appear to have strengths that differ depending on whether they’re measured in radio or X-ray light. And, perhaps most bafflingly, X-ray measurements sometimes imply the shocks are too weak to accelerate electrons at all, seemingly contradicting the very existence of radio relics.Now, a new study led by researchers at the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany may have finally resolved those mysteries.Using high-resolution simulations, the team traced the formation and evolution of radio relics and successfully reproduced the puzzling behaviors seen in real observations. Their findings offer the clearest picture yet of how these enigmatic structures form and why they look the way they do.”Key to our success was tackling the issue using a range of scales,” study lead author Jose …
