Home / Science / Greener, Brighter Comet 3I/ATLAS Approaches Earth
Greener, Brighter Comet 3I/ATLAS Approaches Earth
13 Dec
Summary
- Comet 3I/ATLAS is rapidly becoming brighter and greener.
- Intense solar heating is causing significant surface changes.
- Earth will encounter the comet within 170 million miles soon.

Interstellar comet 3I/ATLAS is exhibiting a dramatic transformation, becoming noticeably greener and brighter as its encounter with Earth nears. New observations from the Gemini North telescope reveal that intense solar radiation is causing significant surface changes, including the sublimation of ice and the release of dust. This process is forming a glowing coma and tail, with a distinct green hue now visible, which was absent in earlier observations.
The shift in color from a previous redder appearance to its current green glow suggests emerging molecules due to intense solar heating exposing fresh subsurface material. Scientists are studying these changes to understand the comet's internal composition. The comet is set to pass within 170 million miles of Earth on December 19, 2025, with its future activity remaining uncertain due to the delayed reaction of comets to solar heat.
As the third discovered interstellar object, 3I/ATLAS is estimated to be the largest and oldest visitor of its kind. While its hyperbolic orbit ensures it will not return, astronomers are meticulously tracking it from dozens of observatories worldwide. The goal is to gather data on its size, trajectory, and composition, hoping to unlock secrets about early star systems and galactic formation. Experts have dismissed theories of artificial origins, confirming its natural cometary behavior.



