Light is one of the most mysterious phenomena in nature. We need it; indeed we can barely function without it — but at the same time we understand very little about it.

What does light consist of? Is it composed of particles waves or some combination of the two? Why does the speed of light represent the greatest velocity that any material entity is capable of reaching? And the most puzzling question of all: How is it that the speed of a ray of light remains constant regardless of the speed or velocity of its source? How can it be that a beam of light from a lamp that is approaching and another beam of light from a lamp that is growing rapidly distant both move through space at an identical speed?

It was this latter bizarre discovery that laid the foundation for Einstein’s theory of relativity which maintains that the speed of light is an absolute constant whereas other parameters that were once thought to be unchanging such as space (the space between point A and point B) or the rate of the passage of time are in fact relative and vary so that the speed of light will remain unchanged in every situation. It appears that even now 100 years after this theory was first introduced people still have trouble digesting its radical implications which serves to highlight the enduring peculiarity of that force called light.

In the Torah and in Chazal’s teachings light and its derivatives occupy a special place of honor. Shlomo HaMelech teaches that “neir mitzvah v’Torah ohr — a mitzvah is a candle and the Torah is light” (Mishlei 6:23). Similarly the light of the menorah in the Beis HaMikdash symbolizes the light of Torah (see Bava Basra 25b and HaAmek Davar Shemos 27:20). Other psukim tell us that “the soul of a man is the candle of Hashem” and “light is sown for a tzaddik.” In the Kabbalah as well the concept of light provides important analogies to various mystical dimensions of the Torah.

The analogies to light with which the Torah is replete can be understood on a practical level. Light opens a person’s eyes illuminates his path through the darkness of the material world saves him from pitfalls that await him on his way and helps him to navigate safely to his life’s destination.

Light too is a union of paradoxical attributes. In some ways it has the characteristics of a physical concrete particle as its photons occupy a defined location in space and time. Yet in other ways it has the characteristics of a wave which is a much more abstract and ambiguous entity. These two aspects of light add up to only a partial description of what is in its entirety a much larger picture which is exceedingly difficult for a limited human imagination to grasp. It could well be said that of all the phenomena in nature light comes closest to partaking of the spiritual in the way it manifests as both wave and particle.

There is a fundamental difference between light and other matter. While other matter has an independent mass that continues to exist regardless of whether it is in motion or at rest light has no “mass at rest.” The existence of light depends on the energy that is produced by the intense speed at which it moves. Light itself has no mass; it is pure energy and nothing more. If you arrest the motion of light you have wiped it out of existence.

Because light has no independent mass it is capable of reaching the highest possible speed of anything in nature — the speed of light. In order for ordinary matter to reach this speed it would first have to be transformed into pure energy. For this reason light can be seen as a sort of upper boundary on the natural world and a point of transition between the natural and the supernatural. Perhaps this is the reason that that spiritual greatness is also described in terms of light. What is spiritual greatness if not the elevation of something material to the world of the spiritual?

Enter Dr. Yaakov Lerner chief scientist at the Institute for Science and Halacha in Yerushalayim who “sheds some light” on light itself from other interesting angles. Over the course of his career first in the Soviet Union and then after emigrating to Eretz Yisrael Dr. Lerner has dedicated a good deal of thought to the subject of light. His insights in this area could fill an entire “enlightening” volume. Dr. Lerner’s thoughts flow forth freely on the spiritual and moral messages light embodies and the fact that a number of its attributes were alluded to in ancient works.