3I/ATLAS already made its closest pass by Earth on December 19, 2025, and it is now heading back out of the solar system and will not return.

Quick Scoop: When 3I/ATLAS Passed Earth

  • 3I/ATLAS is an interstellar comet, the third known object to visit our solar system from interstellar space.
  • It reached its closest point to the sun (perihelion) on October 29, 2025, at about 1.36 AU from the sun (between Earth and Mars).
  • Its closest approach to Earth was around December 19, 2025, at roughly 1.8 AU away, about 168–170 million miles (270 million km).
  • Even at closest approach, it was far beyond Earth’s orbit, inside the asteroid belt, and posed no danger to our planet.
  • As an interstellar object on a hyperbolic trajectory, 3I/ATLAS will not loop back; it is leaving the solar system after this one-time fly-through.

Observations and “latest news”

  • Space agencies like NASA and ESA coordinated observations from Mars orbiters, Jupiter-bound probes, and major space telescopes (Hubble, JWST, JUICE, Europa Clipper, etc.).
  • Much of the detailed science data (for example from ESA’s JUICE spacecraft) is scheduled to arrive and be analyzed into 2026, so new scientific papers and results are expected over time.

In short: if you’re wondering “when will 3I/ATLAS pass Earth?” — the key date was December 19, 2025, and that flyby has already happened.

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Learn when interstellar comet 3I/ATLAS passed Earth, how close it came on December 19, 2025, what telescopes and spacecraft observed it, and why this one-time visitor will never return.

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