A cosmologist is someone who studies the physical universe. Cosmologists are interested in how the universe formed, what is happening to the universe, and what the place of humans within the overall framework of the universe might be. People have long been interested in the nature of the universe, and cosmology has been a part of human life for thousands of years, but it only acquired a scientific bent more recently.
Cosmologists are knowledgeable in several scientific fields. They usually have an extensive familiarity with physics, because physics knowledge is critical for grasping many concepts in cosmology. They also know astronomy, the science of identifying, naming, and describing the various objects in the universe. A cosmologist often works as an experimental scientist, testing hypotheses about the universe and making observations of the parts of the universe which are visible from Earth to find more avenues of exploration.
A wide variety of theories about the nature of the universe have been proposed, from the idea that it was created by God to the suggestion that it was a random spark of happenstance in which a sequence of events occurred in a particular way to trigger the creation of the universe. What most cosmologists know about the universe is that humans do not know very much about the universe, and that there is a lot of room for additional study. A cosmologist can choose from a wide variety of specialties within the field of cosmology.
Cosmologists are interested in the physical objects in the universe, as well as their relationship to each other. They are also intrigued by the movement of celestial bodies, along with the formation and destruction of various objects in the universe. To aid them in their work, cosmologists use a variety of tools including high powered telescopes, specialized radio telescopes which literally listen to the universe, and Earth-bound tools like particle accelerators and scientific laboratories for the purpose of testing theories about the universe.
Someone interested in a career in cosmology should plan on starting early, preferably in high school with a strong set of math and science courses. In college, a future cosmologist may study in a cosmology program, or he or she may choose to come at the field from the perspective of astronomy, physics, or astrophysics. Most cosmologists have performed advanced graduate work in the field, and many work as teachers and researchers at universities around the world. Others work for private scientific institutions, or government agencies with an interest in the field, such as the National Aeronautics and Space Administration in the United States.