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3I/ATLAS Nears Perihelion Behind the Sun as Scientists Prepare Focused Observations

Agencies pivot to spacecraft observations during the brief blackout from ground telescopes.

Overview

  • The interstellar object is at solar conjunction and is expected to reach perihelion around October 29–30 at roughly 1.4 astronomical units from the Sun.
  • ESA assets tracked a close pass by Mars in early October, JUICE is set to observe near peak activity, and JWST and other facilities plan follow‑ups in December.
  • The International Asteroid Warning Network and the Minor Planet Center will lead a coordinated global astrometry campaign from November 27, 2025 to January 27, 2026.
  • Astronomers report unusual features including a sunward jet/anti‑tail, nickel‑rich emissions with low water, and strong polarization that differ from typical comets.
  • NASA and many specialists say 3I/ATLAS poses no threat and behaves as a natural comet, while Avi Loeb and Michio Kaku advance technosignature hypotheses that remain unsubstantiated.