- The processes whereby energy is shifted about within and between celestial objects. The term encompasses energy movement within atmospheres (meteorology is more or less a subsidiary problem within energy transport), oceans, and in astronomy, gas and dust clouds as well as stars. Within stars it attains its greatest complexity. Thus the energy produced in the Sun appears at its core in the form of energetic gamma rays. It travels outwards by means of radiation, interacting with atomic particles on the way in a journey which takes many weeks, losing energy as it goes and being shifted mainly into the visible wavelengths which dominate the solar spectrum. Only in the outer layers does convection seem to take over as the dominant mechanism, by means of convection cells which bring the energy to the surface.