Interstellar Comet 3I/ATLAS Develops Visible Tail as it Approaches earth, Offering Clues to Planetary System Formation
Washington D.C. - September 5, 2025 – Newly released images reveal a developing tail on the interstellar comet 3I/ATLAS, as the celestial visitor continues its journey closer to Earth. the observations, captured on Thursday, September 4, 2025, offer scientists a rare possibility to study a comet originating outside our solar system and gain insights into the formation of planetary systems.
Discovered on July 1, 2025, by the ATLAS (Asteroid Terrestrial-impact Last Alert System), 3I/ATLAS is only the third interstellar object ever detected within our solar system. The previous two were ‘Oumuamua (1I/2017 U1), discovered in 2017, and 2I/Borisov, found in 2019.
Currently 238 million miles (384 million kilometers) from Earth, 3I/ATLAS is projected to make its closest approach to the sun at the end of October. Its closest approach to Earth will occur in December, at a distance of 167 million miles (269 million kilometers) – farther than the distance between Earth and the sun.
The latest images, collected in collaboration with the Shadow the Scientists initiative, showcase the comet’s widening coma and the emergence of its tail, stretching approximately 1/120th of a degree across the sky. The images were obtained using the Gemini South telescope and its Gemini Multi-Object Spectrograph (GMOS) instrument.
“As 3I/ATLAS speeds back into the depths of interstellar space,this image is both a scientific milestone and a source of wonder,” said University of Hawaii Institute for Astronomy astronomer Karen Meech,team leader,in a statement. “It reminds us that our solar system is just one part of a vast and dynamic galaxy, and that even the most fleeting visitors can leave a lasting impact.”
Crucially, initial observations suggest that 3I/ATLAS’s chemical composition is remarkably similar to that of comets originating within our solar system. This finding supports the theory that the processes involved in planetary system formation are consistent across different stars. Comets are believed to form concurrently with planets and asteroids,offering a snapshot of the conditions present during a system’s birth around 4.6 billion years ago.
