3I/ATLAS oddities might increase as it emerges from Sun's glare - 'If 5 billion tons of gas...'

The Lowell Discovery Telescope captured an image of 3I/ATLAS post-perihelion on October 31. The observatory photo is supposedly the first officially released image of the interstellar comet. Several astronomers had been watching it as it approached the Sun, at which time it underwent some changes. Solar observatories STEREO, SOHO and GOES-19 saw the comet and noticed three things. 3I/ATLAS had rapidly brightened near the Sun. While this is an expected phenomenon, since dust reflects light. But in the case of this alien comet, the brightness came much faster than anticipated. It also showed non-gravitational acceleration, something it did for the first time. The Atacama Large Millimetre Array (ALMA) gathered data about this occurrence. 3I/ATLAS also became bluer than the sun, when ideally comets turn red at perihelion as the dust scatters the sunlight.

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Why did 3I/ATLAS brighten near the Sun?

Scientists tried to explain the reason for the sudden brightness exhibited by 3I/ATLAS. , Qicheng Zhang of Lowell Observatory and Karl Battams, an astrophysicist at the Naval Research Laboratory (NRL) in Washington, DC, wrote in a paper that the reason for "3I’s rapid brightening, which far exceeds the brightening rate of most Oort cloud comets at similar r [radial distance], remains unclear." They say that the reason for it could be the speed at which it approached the Sun. Besides, it also speaks volumes about the internal composition of 3I/ATLAS, which is likely different from that of the nuclei of Oort cloud comets.

Also Read: 3I/ATLAS Live Tracker: Did 3I/ATLAS do anything strange near the Sun? Yes, 3 things

Avi Loeb says 3I/ATLAS might soon have another anomaly

"Oddities in nucleus properties like composition, shape, or structure — which might have been acquired from its host system or over its long interstellar journey — may likewise contribute [to the rapid brightening]," the researchers wrote. 3I/ATLAS passed its closest point to the Sun on October 29, 2025, eight days after solar conjunction. Meanwhile, Harvard scientist Avi Loeb argues that if 3I/ATLAS is a natural comet, then "the non-gravitational acceleration must have resulted from it losing at least 15% of its mass." He says that the surrounding gas must measure over 5 billion tons and should be observable during upcoming observations. However, if this is not the case, then non-gravitational acceleration will be the 10th anomaly of 3I/ATLAS, since it shouldn't happen in the absence of a massive coma.

Observatories and astronomers around the world are working to catch a glimpse of 3I/ATLAS as it emerges from the sun's glare. The Lowell Observatory's image is one of the first post-perihelion. The PUNCH mission, a group of small satellites studying the Sun, also grabbed a look at the interstellar comet near the Sun.