Interstellar Comet 3I/ATLAS Approaches Solar System
Comet 3I/ATLAS, the third known interstellar object, is approaching the solar system, with its closest approach to the Sun expected in late October 2025.
Comet 3I/ATLAS, the third known interstellar object to enter our solar system, is currently approaching the Sun. Discovered on July 1, 2025, by the ATLAS telescope in Chile, the comet is exhibiting increased activity as it nears the Sun, with a growing tail of dust and gas.
As of early September 2025, 3I/ATLAS is approximately 238 million miles (384 million kilometers) from Earth. It is expected to reach its closest point to the Sun on October 29, 2025, at a distance of about 1.36 astronomical units (126 million miles or 203 million kilometers), which lies between the orbits of Earth and Mars.
The comet will make its closest approach to Earth on December 19, 2025, at a distance of approximately 168 million miles (270 million kilometers).
3I/ATLAS is estimated to be between 320 meters and 5.6 kilometers (1,050 feet and 3.5 miles) in diameter.
This comet is notable for its high velocity and hyperbolic trajectory, confirming its origin from outside the solar system.
Astronomers are closely monitoring 3I/ATLAS to study its composition and behavior, offering a rare opportunity to observe material from another star system.