JWST’s eyes on an alien world

COMMENTARY Download: icon PDF icon Figure icon Endnote


A compilation of the transmission spectra of WASP-39b from four observational modes of JWST in the Transiting Exoplanet Community ERS program. Important chemical species are identified. The horizontal axis is in units of microns.

Our galaxy is believed to have more than a hundred billion planets, with over 5,000 of them discovered so far. Of these, only around 50 have unveiled their composition beyond the most prevalent hydrogen and helium. Why is it so difficult? Unlike the exploration of planets within our Solar System where we can send probes to gather samples, studying exoplanets is more akin to wine tasting—we must rely on our sense of smell. Remote sensing is currently the only approach available for characterizing exoplanets.