The National Laboratory for Research in Optical and Infrared Astronomy (NOIRLabfor the English acronym) published a photo showing that the 3I/ATLAS has undergone a major change.
The picture was taken after the passage of Dragons due to its perihelion (closest point to the Sun) and the scientists explained why this change in the object occurred.
The event occurred just days before the phenomenon made its closest approach to Earth. The astronomical community eagerly awaits this moment as experts provide instructions on how to observe the visitor interstellar.
On December 12th NOIRLab He uploaded a picture on his website showing that Comet 3I/ATLAS had one chromatic variationwhen purchasing a color Green weak.
According to the lab, the photo was taken by a team of scientists using the Gemini North telescope in Hawaii on November 26, days after the comet’s perihelion.
The ATLAS had different colors, and when Gemini South, the Gemini Observatory’s other telescope, observed it in late August, it actually had one reddish body.
According to NOIRLab, this red-to-green transition was created by light emitted by gases present in the comet’s coma, which are released as the object heats up. Among them is the diatomic carbon (C₂)a highly reactive molecule made of two carbon atoms that emits radiation in wavelengths that correspond to color Green.
Days before the American laboratory’s publication, the head of the Egyptian Astronomical Society, Osama Fathi, also uploaded an image to the Internet showing that ATLAS has a greenish hue.
NOIRLab added that one of the mysteries surrounding this phenomenon is that it is still unknown how it will evolve as it moves away from the Sun’s proximity and begins to cool.
Many comets may have a delayed response to the sun’s heat because it takes a long time to travel through the comet’s interior, and a delay can trigger or cause the evaporation of new chemicals burst of the object.
He 3I/ATLASfirst reported on July 1, 2025, is the third interstellar object known (hence the name “3” “I”), after the discovery of 1I/Oumuamua in 2017 and 2I/Borisov in 2019.
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However, this comet presents a number of Special featuressuch as very high speed and enormous size, which make it a different species than its predecessors. Therefore, since its appearance, the astronomical community has been waiting for it to come close to our planet and then be able to study it in detail.
After NASA reported that this situation would occur in December, the European Space Agency (ESA) went one step further and set the exact date on which the comet will reach the closest point to Earth: December 19th.
Despite the enthusiasm of fans, this is the truth It will not be possible to view the ATLAS with the naked eye. not even with binoculars. What’s more: The ESA assumes that the object loses some of its brightness as it approaches our planet, so that it could not be observed even with small telescopes.
Finally, the comet alone can be seen with medium and large telescopesand experts say the best opportunities to capture it are in remote locations with low light pollution.
Despite the above, some websites offer an alternative to creating one virtual tracking of the 3I/ATLAS flight path. Below, TheSkyLive, A website specializing in astronomy offers one of the most comprehensive options. This link simulates a kind of interactive sky in which you can see the planets and stars, with the sun in the center.
The ATLAS route is marked there in real time with yellow dots, as well as where it has been in the last few hours and where it will be in the next few hours. Additionally, several statistics are listed in the top left corner of the page, including the distance separating the object from the Earth and the Sun.
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