Astronomers now have a way to figure out how gas-giant planets form, thanks to a discovery by the James Webb Space Telescope (JWST) of ammonia "isotopologues," which are molecules that contain the same elements but with differing numbers of neutrons.
The nucleus of an atom is made from a bunch of protons and neutrons, and while the number of protons within an element does not change — for example, carbon atoms always contain six protons and nitrogen atoms always have seven protons — the number of neutrons can vary. When such variation occurs, an atom turns into an isotope. When isotopes are part of a larger molecule, we call them isotopologues.
