- Detected by the ATLAS survey telescope in Chile in June 2025.
- It is an interstellar comet, meaning it originated outside the solar system.
- Moves at a speed of 57–68 km/s relative to the Sun.
- Its hyperbolic orbit indicates it will pass through the solar system and never return.
- Closest approach to Earth: 270 million km; closest to the Sun: 210 million km (October 2025).
- Size: Estimated 10–30 km wide, larger than previous interstellar objects ʻOumuamua (2017) and Borisov (2019).
- Composition: Exhibits a coma and reddish hue, suggesting complex organics or water ice.
- Possible origin: Milky Way’s thick or thin disk, potentially from an ancient star system.
- Scientists have discovered 3I/ATLAS, possibly the oldest known comet, which may predate the solar system by over 3 billion years.

