On seven distant worlds, the wind races across burning skies at thousands of kilometres per hour. Yet astronomers discovered something unexpected: the hotter the planet, the slower its wind blew. This discovery, published in Nature Astronomy on June 2, 2026, provides strong evidence for magnetic fields on planets beyond our Solar System.
These planets are ultra-hot Jupiters, giant gas planets that orbit very close to their stars. Wind speeds there range from 7,200 to over 25,000 kilometres per hour. However, standard physics suggests that hotter planets should have faster winds because they have more energy. These planets did the opposite.
The answer, scientists concluded, is magnetism. The atmospheres of these scorching planets are partly ionized, meaning some gas carries electric charge. When charged particles move through a magnetic field, they experience a force that resists their movement, like an invisible brake.
Researchers used the ESPRESSO spectrograph on the Very Large Telescope in Chile and the Gemini North telescope in Hawaii to measure these distant winds. They discovered that the magnetic fields are comparable to those in our Solar System, roughly four times stronger than Saturn's.
Lead author Julia Seidel explained that this breakthrough opens a new window for exoplanet research. Magnetic fields may shield atmospheres from being stripped away by stellar winds, helping planets keep their gases and water. This discovery could eventually aid the search for potentially habitable worlds beyond our Sun.