Fusion occurs in the sun's innermost core, when two atoms merge, releasing energy and light in the process. Photons of light are first created in the sun's center. Over tens of thousands of years, the photons travel a "drunken walk," zigzagging their way from atom to atom until they reach the surface.

How does the sun produce light?

The Sun produces light by a nuclear reaction called fusion. As atoms of hydrogen combine to form helium, they produce vast amounts of heat and light. ... The central core of the sun, where heat and light are produced, has a temperature of 15 million degrees.

Does the sun transmit or emit light?

Our Sun emits light at progressively shorter wavelengths, too: the ultraviolet, X-ray, and even gamma-ray parts of the spectrum. But most of the Sun's light is in the infrared, visible, and ultraviolet parts of the electromagnetic spectrum.