Recently, the Gemini North telescope in Hawaii captured stunning new images of the interstellar comet 3I/ATLAS. Since its close approach to the sun in late October, the comet has brightened and developed a greenish hue. This change suggests it may soon release more cometary material as it moves toward Earth for its closest encounter next week.
The images, taken on November 26, show 3I/ATLAS in one of its most energetic phases yet. Intense solar radiation is heating the comet, causing its icy surface to vaporize and release gas and dust. This forms a bright atmosphere called a coma around the comet, along with a long tail stretching behind it.
Using filters in different colors, scientists found that the gas in the comet’s coma now glows faintly green. This wasn’t the case just a few months ago. The greenish tint comes from diatomic carbon (C2), a compound that emits green light when heated. Similarly, other comets, like 12P/Pons-Brooks, have shown a greenish glow during their journeys past the sun.
When first spotted in August, 3I/ATLAS appeared redder. This indicates that it is shedding new molecules as it heats up, offering clues about its mysterious composition.
As 3I/ATLAS approaches Earth on December 19, it will come within 170 million miles (270 million kilometers). Experts believe this could lead to more surprises, as comets can undergo sudden changes due to the sun’s heat. “Many comets show a delayed reaction to the sun’s warmth,” say representatives from NOIRLab. This means new chemicals might be activated as the comet cools down after its solar encounter.
3I/ATLAS is notable for being the third interstellar object discovered, following 1I/’Oumuamua and 2I/Borisov. First detected in June, it is moving at an astonishing speed of about 130,000 mph (210,000 km/h) on a hyperbolic trajectory that won’t bring it back again. Scientists believe it’s one of the largest and possibly the oldest interstellar objects observed, characterized by features like large jets and signs of past radiation exposure in space.
As astronomers monitor this comet closely, they hope to learn more about its origins and what it can reveal about our galaxy’s history. For more information on comets, check out this detailed article on their dynamics and behavior.
