Real-Time Watch: Interstellar Comet 3I/ATLAS Begins Exit from Solar System

Comet 3I/ATLAS begins its irreversible escape from the solar system, offering Earth observers a final chance to witness its interstellar journey.

Discovered on July 1, 2025, the object was confirmed as the third interstellar visitor to the solar system. A livestream event on January 16 at 5 p.m. EST (2100 GMT) will feature a 14-inch Schmidt-Cassegrain telescope in Manciano, Italy, providing real-time observations.

The Virtual Telescope Project describes this as 'a very precious opportunity to personally see, in real-time, the interstellar comet 3I/ATLAS, one of the most important discoveries of the last decade.' The comet reached perihelion on October 29, 2025, and passed Earth at a distance of 168 million miles (270 million km) on December 19. Its trajectory will carry it past Jupiter in March 2025 at 33.4 million miles (53.7 million km) before exiting the solar system.

Modeling of 3I/ATLAS’s trajectory suggests it will cross the Oort cloud boundary and enter interstellar space. This conclusion is based on orbital mechanics analysis rather than direct observation of the Oort cloud passage. The comet’s interstellar origin was confirmed through its hyperbolic orbit, which exceeds the solar system’s escape velocity.