"hydrogen escape" . . "swept into interplanetary space" . . . . . "Atmospheric escape" . "impact erosion" . "X-ray and ultraviolet irradiation would destroy it" . "Jeans escape" . . "escapes into space" . "lost" . "escaped" . "loss of the atmosphere into space" . "leakage of gases" . "escape from the atmosphere" . "hydrodynamic escape" . . "winds" . "escape" . "loses" . "atmospheric escape" . "atmosphere depletion" . "escaping methane atmosphere" . "escape the atmosphere" . "sputtering escape" . "escape mechanisms" . "atmospheric loss processes" . "suprathermal" . "Atmospheric escape" . "evaporate an atmosphere" .