ESA’s CHaracterising ExOPlanet Satellite (CHEOPS) has revealed a four-planet system whose outermost world is a small and rocky planet — not a gas giant. The unexpected arrangement around the nearby red dwarf star LHS 1903 suggests that the outermost member of the system formed long after the others, providing the strongest observational hint yet that planets can emerge in gas-poor conditions once thought impossible. An artist’s impression...
