Astronomers have captured striking new images showing that the interstellar comet 3I/ATLAS is not only brightening but also taking on a distinct green hue as it approaches Earth. Observed with the Gemini North telescope in Hawaii, the comet’s transformation follows its close approach to the Sun at the end of October, when its surface heated up, causing ice and dust to vaporise and forming a glowing coma and an elongated tail. Once much redder, the comet now emits a faint greenish light, revealing fresh molecules released into space according to a photo release by NOIR Lab. One of only three interstellar visitors ever detected, 3I/ATLAS presents a rare opportunity to study the makeup, behaviour, and origins of objects from beyond our solar system.
Comet 3I/ATLAS emits faint greenish light revealed in new image
Comet 3I/ATLAS has entered one of its most active phases yet. Solar heating causes the sublimation of ice and the release of dust, forming a bright coma that surrounds the nucleus. The comet’s tail, illuminated by sunlight, fans out in space, marking the path this interstellar traveler has taken. Observations made with multiple colour filters-blue, red, orange, and green-are noticeably more greenish, suggesting that its composition may have altered since the pre-perihelion observations back in August.The green glow comes from diatomic carbon (C2) molecules. When these are excited by sunlight, they emit green light. In itself, this is nothing special: most comets from the solar system display this sort of emission. However, it is surprising in the case of 3I/ATLAS, which had earlier been observed as an entirely red comet: the colour change to green was a spectacular demonstration of how new molecules are released when the comet is warming. “The Colour Change is a natural chemical process”, scientists put in and clarified; obviously, it has nothing to do with any extraterrestrial activities that went viral on the internet.
Comet 3I/ATLAS nears its closest approach on 19 December from Earth
The astronomers expect further brightening or new outbursts with 3I/ATLAS approaching closest at around 270 million kilometres from Earth on 19 December. This is because comets can be quite slow to respond to solar heating, which could then elicit new jets of gas and dust. Their observations might enlighten cometary behaviour and the physical processes of interstellar objects anew.3I/ATLAS is the third interstellar visitor, following 1I/‘Oumuamua and 2I/Borisov. It travels in a hyperbolic orbit at a speed of approximately 210,000 km/h and thus will never return to our solar system. Probably the biggest and oldest interstellar object detected so far, it carries clues about the pristine conditions of other star systems. Ongoing monitoring by observatories around the world is underway to show its size, trajectory, and composition, providing insight into the distant parts of our galaxy.
Why studying 3I/ATLAS necessary
The study of 3I/ATLAS allows scientists to probe material in stellar systems that formed billions of years ago. With its icy surface, sun-facing jets, and complicated make-up, 3I/ATLAS represents an ideal natural laboratory for determining the origins and evolution of interstellar bodies. Continued observations of this unusual visitor will reveal insights into galaxy formation and early star system contributions to the cosmic neighborhood in which we live today.Also Read | Massive 12-mile-thick rock layer discovered beneath Bermuda challenging Earth’s mantle understanding
