High-speed winds on a distant planet act as a chemical conveyor belt, dragging molecules to the nightside faster than they can react.
On the exoplanet NGTS-10A b, the atmosphere is in a state of constant disequilibrium because of the extreme weather. Huge winds blast chemicals from the permanent day-side to the permanent night-side at thousands of miles per hour. This movement is so fast that the chemistry of the night-side never has time to settle into a natural state. Astronomers are essentially watching a giant, planetary-scale chemical factory that never stops running. This proves that we cannot understand what an alien world is made of without also understanding its wind speeds. It adds a whole new layer of complexity to the search for signs of life on other planets.
Horizontal transport as a source of disequilibrium chemistry on the nightside of a hot exoplanet
arXiv · 2605.04936
Hot Jupiters have temperature gradients of several hundreds of degrees between their permanent day and nightsides. In equilibrium, the primary carbon reservoir is expected to transition from CO on the dayside to CH4 on the nightside. Theory predicts that the atmospheric circulation, characterised by km/s winds, can advect chemical species from the dayside to the nightside faster than the time needed for the CO-to-CH4 chemical reaction to reach equilibrium. However direct evidence of this process