Cosmology is a branch of astronomy which studies the structure, origins, and space-time relationships of the universe. It is also a branch of metaphysics that deals with the nature and origin of the universe.
Crewman Mortimer Harren studied this field. He held five advanced degrees in theoretical cosmology and needed one year of hands-on experience in order to qualify for the Institute of Cosmology on Orion I, so he joined the crew of the USS Voyager. He had worked on Schlezholt's Theory of Multiple Big Bangs and studies in dark matter proto-comets. (VOY: "Good Shepherd")