The Bible says that the first thing God created in the beginning was light - jehi or!
The amazing fact of human existence is that the study of this first thing, light, has opened to human race the study of the deepest structures of creation. Light is of such fundamental importance that struggling with its secrets has opened up major fields of research in modern science - not least among them nuclear physics. Or to put it in the somewhat less raving style of English wikipedia "the study of light, known as optics, is an important research area in modern physics."
"Light, which is emitted and absorbed in tiny "packets" called photons, exhibits properties of both waves and particles. This property is referred to as the wave–particle duality."
Sir Isaac Newton considered light to be tiny bodily pieces (corpuscles) flying around, reflected by mirrors and caught somehow by the eye. Christiaan Huygens, on the other hand, suggested that light is a series of waves emitted to every direction in some light carrying medium he called luminoferous ether. Maxwell's electromagnetic theory gave the wave theory a significant push as scientists were able to use it in order to explain the behaviour of light.
Now, many people were quite happy about the state of affairs and considered the wave theory a great triumph of 19th century science. What it was.
Albert was not happy with those small anomalities. We know that he loved beautiful theories - and as long as the explanation was not beautiful to his mind it was not satisfactory.
So he used his significant ability to conceptualize things and figured out something that could explain the properties of light in a beautiful manner.
This changed the course of human history.