 By the 1970s, the rate at which short-period comets were being discovered was becoming increasingly inconsistent with their having emerged solely from the Oort cloud.For an Oort cloud object to become a short-period comet, it would first have to be captured by the giant planets.In a paper published in "Monthly Notices of the Royal Astronomical Society" in 1980, Uruguayan astronomer Julio Fernández stated that for every short-period comet to be sent into the inner Solar System from the Oort cloud, 600 would have to be ejected into interstellar space.