First Detection of Exoplanetary Cannabinoids: Evidence for THC and CBD in the Atmosphere of K2-18b

We report the first unambiguous detection of cannabinoid molecules in an exoplanetary atmosphere. Using 420 hours of JWST observations combining NIRSpec and MIRI instruments, we identify spectroscopic signatures of tetrahydrocannabinol (THC; ${\mathrm{\Delta }}^9$-C${}_{21}$H${}_{30}$O${}_2$) and cannabidiol (CBD; C${}_{21}$H${}_{30}$O${}_2$) in the transmission spectrum of the temperate sub-Neptune K2-18b. The THC feature at 2.42~$\mu$m is detected at 9.2$\sigma$ significance, while CBD absorption at 3.69~$\mu$m reaches 7.8$\sigma$. We additionally report a mysterious feature at exactly 4.20~$\mu$m detected at 4.20$\sigma$ (the probability of this coincidence is discussed extensively). Our atmospheric retrievals using the novel $\mathtt{\text{TerpeneRetrieval}}$ code indicate a CBD-to-THC ratio of 0.40$\pm$0.08, classifying K2-18b as a balanced hybrid'' world according to standard terrestrial cannabis taxonomy. We introduce the Cannabis Habitable Zone (Green Zone’‘) framework and demonstrate that K2-18b lies squarely within it. We explore multiple production mechanisms including biogenic synthesis, abiotic photochemistry, exogenous delivery via ``space nuggets,’’ and deliberate atmospheric engineering by an advanced civilization. These findings suggest that K2-18b may host conditions suitable for advanced photochemistry, atmospheric relaxation processes, and possibly the most chill civilization in the galaxy. If confirmed by independent observations, this represents a paradigm shift in our understanding of biosignatures and the prevalence of recreational organic chemistry in the cosmos.