The Chanukah miracle revolves around light - a small cruse of pure oil that was only enough for one night, but burned for eight. To a physicist, light is fascinating because it is one of the least tangible of all physical phenomena. Let's compare light to the equally familiar senses of sound and smell. Sound is a wave, which propagates by rippling through the air. These vibrations are transferred to the bones of the middle ear, which produce the sensation of sound. Smell is caused by tiny, airborne particles that lodge into smell receptors in the nose, which are then recognized by the brain.

Light is different from the two in that it seemingly has no physical properties whatsoever, even though we can observe its effects. It is a wave, but does not need a medium to wave in. It is a particle, but takes up no space. Light is ethereal, intangible. For this reason, light often serves as a metaphor for spirituality.

On Chanukah, we primarily celebrate the miracle of the oil, and not the Maccabean military victory over the Greeks. The Greeks' aim was not to subdue the Jewish people physically, but to destroy them spiritually. They attempted to turn the Jewish faith into a culture like any other. The Jews were free to study the Torah as a piece of literature, as long as they did not regard it as divine. The Greeks permitted the Jews to observe their customs and traditions, as long as they made sense to human intellect. However, those mitzvot that were beyond intellect were strictly forbidden and punishable by death.

When the Greeks vandalized the Holy Temple, they took all the jars of oil with the priestly seal and defiled them. They wanted to highlight the "absurdity" of declaring one type of oil more pure than the other, even though they were physically indistinguishable. After the Jews won their miraculous victory over the Greeks, they rededicated the Temple, and found only one jar of pure oil with which to light the Menorah. G-d miraculously made the oil burn for eight days.

G-d chose to reveal Himself in the Holy Temple through the medium of light - the lights of the Menorah. Physical light is the closest approximation of spiritual light, and thus served as a vehicle to reveal G-d's presence in the universe. The holiday of Chanukah was established because of the miracle of the lights - to demonstrate firmly that G-d dwells in our midst.

Prof. Yirmiyahu Branover is chairman of the Center of Magnetohydrodynamic Studies and Training at Ben-Gurion University.