MeerKAT Detects Radio Signal From Interstellar Comet 3I/ATLAS — OH Lines Confirm Natural Origin (Nov. 13, 2025)
Dateline: Nov. 13, 2025 South Africa’s MeerKAT radio array has picked up the first confirmed radio signal from the interstellar comet 3I/ATLAS, a detection that strongly supports the object’s natural, cometary identity and undercuts recent “alien probe” speculation. The signal—two narrow features at 1665 and 1667 MHz—matches classic hydroxyl (OH) absorption produced when sunlight breaks apart water vapor outgassed from a warming comet. The Astronomer’s Telegram What astronomers actually detected The team reported OH absorption in both the 1665 MHz and 1667 MHz lines while observing 3I/ATLAS on Oct. 24, 2025, when the comet sat just 3.76° from the Sun