New telescope images interstellar comet 3I/ATLAS confirm that the mysterious object has become brighter and greener since its close approach to the Sun in late October. This increase in activity could herald more bright flares of cometary material as 3I/ATLAS approaches its closest approach to Earth next week.
Filmed November 26th from Gemini North Telescope Atop the dormant Mauna Kea volcano in Hawaii, new images capture the comet in one of its most active phases more. Newly heated by intense solar radiation, the ice on the comet sublimates and spews into space along with tons of dust, forming a bright cloudy atmosphere (coma) around the comet's main body and long glowing tail behind this.
Why does 3I/ATLAS turn green?
Don't rush to blame little green men for the new greenish glow of the comet. Among the gases escaping from 3I/ATLAS is diatomic carbon (C2) is a molecule of two carbon atoms that emits greenish light, according to statement from the National Science Foundation's NOIRLab, which operates the Gemini North telescope along with the Gemini South twin telescope in Chile.
Many solar system comets emit a similar green hue when activated by the sun, including last year's Comet “Mother of Dragons” 12P/Pons-Brooks and recently discovered Comet C/2025 F2 (SWAN).
However, it is noteworthy that 3I/ATLAS looked noticeably redder when it was first created. observed by Gemini South at the end of AugustAccording to NOIRLab, several months before its close flyby to the Sun. This is evidence that 3I/ATLAS is releasing new molecules into space as it warms, offering fresh hints about its mysterious composition.
Is another outbreak coming?
When the comet approaches its closest point to Earth on December 19 (170 million miles or 270 million kilometers from our planet), we may be in for even bigger surprises.
“What remains unknown is how the comet will behave as it leaves the solar vicinity and cools,” NOIRLab representatives wrote in a statement. “Many comets have a delayed response to sensing solar heat due to the time delay required for the heat to pass through the comet's interior. The delay could accelerate the evaporation of new chemicals or trigger a comet outburst.”
3I/ATLAS is the third interstellar object ever discovered, after 1I/'Oumuamua and 2I/Borisov. The comet was discovered in late June as it raced through our solar system at approximately 130,000 mph (210,000 km/h), approaching in a hyperbolic (U-shaped) orbit that would never take it through our neighborhood again.
3I/ATLAS is likely the largest and very likely the oldest interstellar object observed so far. Although it showcases many intriguing features including large jets facing the sun And signs of exposure billions of years spent in interstellar space – the vast majority of astronomers and space agencies agree that this is a typical comet — and not an artificial piece of alien technology, as some viral claims suggest.
Dozens of observatories and spaceship around the solar system closely monitored 3I/ATLAS to better understand its size, trajectory, composition, and origin. An in-depth study may reveal new details about the mysterious border of our galaxy and how some of the earliest star systems in Milky Way formed.
