Interstellar Visitor 3I/ATLAS Just Turned Blue and “Accelerated”—Here’s What Really Happened This Week
Key facts (updated Nov 5, 2025): The story so far: what changed in the last few days While 3I/ATLAS was hidden in the Sun’s glare in late October, it slipped into the fields of view of several solar‑monitoring cameras: STEREO‑A (SECCHI), SOHO/LASCO C3 and NOAA’s GOES‑19 CCOR‑1 coronagraph. A new analysis by Qicheng Zhang (Lowell Observatory) and Karl Battams (U.S. Naval Research Lab) reports an extra‑steep brightening as perihelion approached (scaling approximately as r^‑7.5), and color photometry showing the comet was bluer than the Sun, signaling that glowing gas (not just dust) dominated the visible output near perihelion. This is