Astronomers Observe Interstellar Comet 3I/ATLAS Exiting Solar System
Scientists at Gemini North Observatory in Hawaii conducted real-time observations of interstellar comet 3I/ATLAS as it departs the solar system, providing valuable insights into its composition and trajectory.
In the early hours of November 25, 2025, astronomers at the Gemini North Observatory in Hawaii conducted real-time observations of interstellar comet 3I/ATLAS as it made its way out of the solar system. The event was part of a virtual seminar hosted by Shadow the Scientists, connecting experts and the public through live skywatching sessions.
Discovered on July 1, 2025, by the NASA-funded ATLAS survey telescope in Chile, 3I/ATLAS is the third known interstellar object to pass through our solar system. The comet reached its closest approach to the Sun on October 30, 2025, at a distance of about 1.4 astronomical units, just inside the orbit of Mars.
During the November observation, the comet appeared as a small, fuzzy object drifting among the stars. Spectral analysis revealed a composition rich in carbon dioxide and cyanogen, distinguishing it from typical solar system comets, which are usually water-rich.
The seminar also addressed the comet's age and origin. Studies suggest that 3I/ATLAS is likely between 3 billion and 11 billion years old, indicating it predates our 4.6-billion-year-old Sun. Its trajectory through the galaxy is complex, influenced by encounters with gas clouds, spiral arms, and dark matter, making it challenging to trace back to a specific parent star.
As 3I/ATLAS continues its journey beyond our solar system, ongoing observations aim to deepen our understanding of such interstellar visitors and the broader cosmos.