Unveiling the Secrets of Interstellar Object 3I/ATLAS: A Journey Beyond Perihelion
The NASA SPHEREx spacecraft has revealed a captivating story of transformation and activity in the depths of space.
In December 2025, SPHEREx revisited the interstellar object 3I/ATLAS, and what it discovered was nothing short of extraordinary. Compared to its previous observations in August 2025, this object had evolved into a highly active celestial body, showcasing evidence of complete ice sublimation, a process that transforms it into a fully fledged comet.
The new spectrophotometric images paint a vivid picture. Dust scattered light and thermal emissions dominate, accompanied by gas emissions from various species: CN (0.93 um), H2O (2.7 um), organic C-H (3.2 to 3.6 um), CO2 (4.25 to 4.27 um), and CO (4.6 to 4.8 um). Notably, the CO2 gas-coma extends beyond a 3 arcmin radius.
One of the most intriguing findings is the disappearance of the H2O-ice absorption signature, replaced by scattered light and thermal emissions from organo-silicaceous dust grains. Simultaneously, the H2O gas emission has intensified, becoming 20 times brighter.
Most of the gas comae exhibit circular symmetry, except for the organics-gas comae. Interestingly, a weak pear-shaped dust tail, consistent with large dust grains, has emerged, pointing towards the Sun. The appearance of CN and C-H features suggests their presence within H2O phases or beneath them.
This research, led by C.M. Lisse and a team of experts, has been submitted to RNAAS and covers a range of astrophysics subjects. It invites further exploration and discussion, leaving us with a thought-provoking question: What other secrets might this interstellar object hold, and how will its story continue to unfold?
And this is the part most people miss... the potential for controversy. What if our interpretations are slightly off? What if these findings challenge our current understanding of interstellar objects? Feel free to share your thoughts and theories in the comments below! Let's spark a conversation and explore the possibilities together.
