From Sam Edge, Ringwood, Hampshire, UK
The continuing arguments about the absorption spectrum of the atmosphere of the exoplanet K2-18b shows the difficulty of such research. Who selects the size and contents of the set of molecular spectra against which to compare the planet’s data? The original 20 molecules seems an absurdly low number. That an expansion to 92 gives different results, and then to 650 different again, suggests that one might be able to suggest any number of molecules – either biologically or non-biologically generated on our own planet(31 May, p 19).
I wouldn’t advocate for the end of such research, just that researchers should be humbler about whether they have detected or merely found the possibility of a given molecule.
