3I/ATLAS reaches perihelion behind the Sun as space-borne coronagraphs — STEREO‑A COR2, SOHO LASCO, and GOES‑19 COR1 — capture a reported green‑to‑blue color shift, rapid brightening, and a ~300,000 km luminous envelope. In this data‑driven breakdown we explain what the images really measure, how bandpass/false‑color mapping, Rayleigh scattering, and Wien’s law affect apparent color, and which tests (polarization, spectroscopy, light curves) can confirm what’s actually happening. We cover trajectory geometry (~203 million km, ~770 W/m²), hyperbolic dynamics, low‑inclination approach near the ecliptic, CO₂‑dominated activity far from the Sun, nickel/iron behavior, and the December 19 Earth window when JWST and Hubble can probe lines, continuum, and thermal emission. You’ll see how STEREO‑A, SOHO, and GOES‑19 datasets compare, why “blue” in coronagraph channels isn’t automatically temperature, and which multi‑instrument measurements can distinguish natural comet physics from more exotic hypotheses (technosignatures — speculative). Every claim is labeled [Confirmed], [Reported], or [Debated], with sources so you can verify the data yourself.
Credit to : Celestial Enigma