FTP, name this American astronomer who, in 1951, predicted the existence of a disk-shaped region outside the orbit of Neptune as a source for short-period comets.
In 1936 this scientist went to the University of Chicago, becoming a professor of astronomy and director of the university's Yerkes and McDonald observatories. His achievements include measurement of the diameter of Pluto, the discovery of some satellites of Uranus and Neptune, and the detection of carbon dioxide on Mars.  In the 1960's, he served as chief scientist for the Ranger spacecraft crash-landing probes of the moon. FTP, name this American astronomer who, in 1951, predicted the existence of a disk-shaped region outside the orbit of Neptune as a source for short-period comets.
In 1936 this scientist went to the University of Chicago, becoming a professor of astronomy and director of the university's Yerkes and McDonald observatories.
Gerard Peter {Kuiper}