On Jan. 7th, 2026, the Subaru Telescope joined many of the world's observatories and space telescopes in observing the 3I/ATLAS, the third interstellar object (ISO) detected in our Solar System. This interstellar comet had just completed its closest approach to the Sun, which produced more intense outgassing. By observing the light from 3I/ATLAS' coma, astronomers were able to examine the chemical composition of the comet's interior and produce estimates of the ratio of carbon dioxide to water. Prior observations largely provided insight into the composition of its outer layers, which have been subject to billions of years of cosmic irradiation. As the Subaru team reported in a recent study published in The Astrophysical Journal , their results showed that the ratio of carbon dioxide to water was much lower than that inferred from previous observations by space telescopes, providing clues about the ISO's structure and suggesting that the chemistry of the coma is evolving.…