3I/ATLAS

3I/ATLAS — What We Know (So Far) About the Interstellar Visitor

3I/ATLAS is currently one of the most closely watched objects in astronomy. Discovered on 1 July 2025 by the ATLAS survey telescope, 3I/ATLAS is only the third confirmed interstellar object ever detected passing through our Solar System. Wikipedia+2NASA Science+2

Because of its unusual origin — from outside our Solar System — and its dramatic behavior as it approached the Sun in late 2025, 3I/ATLAS has captured widespread scientific interest. Here’s a summary of what we currently know about it, what recent findings say, and what mysteries remain.

🔭 What 3I/ATLAS Is — and Why It Matters

• Interstellar origin & hyperbolic trajectory: 3I/ATLAS is on a hyperbolic orbit, meaning it is not gravitationally bound to the Sun. Its speed and trajectory show it came from outside the Solar System and will eventually leave — likely never to return. Wikipedia+1

• Close solar approach (“perihelion”): The comet made its closest approach to the Sun on 29–30 October 2025, passing at about 1.4 astronomical units (AU) — just inside Mars’s orbit. NASA Science+1

• Potentially ancient: Studies estimate that 3I/ATLAS could be billions of years old — perhaps 7.6 to 14 billion years, which would make it far older than our Solar System. Wikipedia+1

• Window of observation: After its perihelion and a brief period behind the Sun (solar conjunction), astronomers expect 3I/ATLAS to become visible again in early December 2025. It should remain observable — with telescopes — through at least spring 2026. The Economic Times+1

Because 3I/ATLAS originates from another star system and possibly preserves ancient ices and dust from its birthplace, studying it offers a rare opportunity: a chance to peek into the chemistry and conditions of distant planetary systems — something typically far beyond our reach.