Interstellar comet 3I/ATLAS is approaching Earth for its closest pass
Interstellar comet 3I/ATLAS, the third confirmed visitor from outside our solar system, reached its closest point to the Sun (perihelion) on October 29, 2025, at about 1.36 AU.
Its closest approach to Earth occurs on December 19, 2025, at a safe distance of roughly 1.8 AU, or 270 million kilometers—positioned on the opposite side of the Sun with no risk to the planet.
Discovered in July 2025 by the ATLAS survey in Chile, it travels at speeds up to 68 km/s near perihelion and originates possibly from the Milky Way’s thick disk, potentially over 7 billion years old.
It passed Mars closely on October 3, 2025 (about 29 million km), observed by NASA’s Perseverance rover and orbiters.
Visibility improves from early December via telescopes; Hubble and JWST have imaged it, with more observations planned before it exits the solar system in 2026.
Best viewed mid-to-late December in the constellation near the Sun’s glare, using amateur telescopes under dark skies.
No naked-eye visibility expected due to distance; track via apps like NASA’s Eyes on the Solar System.
