Section 2: Mysteries of Light Figure 3: This furnace for melting
glass is nearly an ideal blackbody radiation source. Source: ©
OHM Equipment, LLC. More info The nature of light was a profound
mystery from the earliest stirrings of science until the 1860s
and 1870s, when James Clerk Maxwell developed and published his
electromagnetic theory. By joining the two seemingly disparate
phenomena, electricity and magnetism, into the single concept of
an electromagnetic field, Maxwell's theory showed that waves in
the field travel at the speed of light and are, in fact, light
itself. Today, most physicists regard Maxwell's theory as among
the most important and beautiful theories in all of physics.
Maxwell's theory is elegant because it can be expressed by a
short set of equations. It is powerful because it leads to
powerful predictions—for instance, the existence of radio waves
and, for that matter, the entire electromagnetic spectrum from
radio waves to x-rays. Furthermore, the theory explained how
light can be cre