In the 1800s, the scientific understanding of electricity and magnetism grew to the point at which it was possible to generate controlled amounts of energy from electricity using generators, and to transport that electricity across large distances. This research led to the understanding of electromagnetism as a force, the transference of electromagnetic energy in the form of waves, and the manifestation of those waves as the electromagnetic spectrum.

Scientists also made major advances in understanding the concept of energy and how it can be manifested in many different forms such as motion, heat, and light. The science of thermodynamics—the study of heat energy and how it is transferred—and its closely related branch of physics, statistical mechanics, were born. These discoveries and their technological applications transformed all of human society: the steam engine, the electric light, and the Industrial Revolution are just a few examples of their effect. Their effect on astronomy was equally significant.