Based on observations and analysis, they attempt to discover laws describing the forces of nature, such as gravity, electromagnetism, and nuclear interactions. They also find ways to apply physical laws and theories to problems in nuclear energy, electronics, optics, materials, communications, aerospace technology, navigation equipment, and medical instrumentation. Astronomy is sometimes considered a subfield of physics. Astronomers use the principles of physics and mathematics to learn about the fundamental nature of the universe, including the sun, moon, planets, stars, and galaxies. They also apply their knowledge to problems in navigation and space flight, and to develop the instrumentation and techniques used to observe and collect astronomical data.
Most physicists work in research and development.
Some do basic research to increase scientific knowledge. Physicists who conduct applied research build upon the discoveries made through basic research, and work to develop new devices, products, and processes. For instance, basic research in solid-state physics led to the development of transistors and then to the integrated circuits used in computers. Physicists also design research equipment. This equipment often has additional unanticipated uses.