Excerpt from the November 2, 1963 issue of SCIENCE NEWS LETTER
A belt of yet-to-be-seen comets lies near the pathway of the farthest planet, Pluto, predicted by Dr. Fred L. Whipple, director of the Smithsonian Astrophysical Observatory, Cambridge, Mass.…
The belt extends out to an undefined distance [and] is distinct from the great cloud of comets that is more than twice as far off and that accounts for the occasional comets we see…. Dr. Whipple said the gravitational pull of the comet belt probably is responsible for disturbances in the planet Neptune’s orbit. This would mean that the belt would be ten times heavier than earth.