They realized that there must be a distant, giant planet just beyond the orbit of Uranus that was tugging along at that orbit, sometimes pulling it along a bit too fast, sometimes holding it back.
Realizaseră că trebuie să existe o planetă gigant la mare distanță, dincolo de orbita lui Uranus, care afecta acea orbită, uneori accelerând-o, alteori încetinind-o.