Christmas, Hanukkah, and Strange Physics: the Theology of Light

Dr Kurlnd holds a PhD in physics from Harvard University. He blogged (not updated since 2019) at, Reflections of a Catholic Scientist.

From Catholic Stand

By Bob Kurland, OblSB, PhD

This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all. First Letter of John 1:5 (KJV)

And they made new holy vessels, and brought in the candlestick, and the altar of incense, and the table into the temple.   And they put incense upon the altar, and lighted up the lamps that were upon the candlestick, and they gave light in the temple. 1 Maccabees 4:48-50 (KJV)

All these fifty years of conscious brooding have brought me no nearer to the answer to the question, ‘What are light quanta?’ Nowadays every Tom, Dick and Harry thinks he knows it, but he is mistaken. Albert Einstein, in The Born-Einstein Letters, by Max Born

INTRODUCTION: CHRISTMAS

When I was a child eighty-seven years ago (more or less),  I would pester my Jewish parents (secular, non-religious) for a Christmas Tree. All around me were the lights of Christmas—on houses, lawns, and downtown department store displays (there was a downtown in those days). Why couldn’t we take part in all that, I wondered.  Despite explanations that we weren’t Christians, that we had our own holiday, Hanukkah, I wasn’t satisfied. The eight lights of the Menorah didn’t hold a candle (pun intended) to those on any modest Christmas tree. Even though there were eight days of gifts, they were small potatoes compared to those my Christian friends received on the one day of Christmas.

Almost 10 years after my conversion to the Catholic faith  I began to understand the full import of Christmas.  During the first few years after my conversion, I did not feel totally comfortable during the Christmas holidays—more like the hungry tramp peering into the restaurant window, an outsider.  To realize the miracle of the Incarnation took a while for me.  Then my prayer before the third decade of the Joyful Mysteries of the Rosary became a request  that Christmas be celebrated as more than the gift-giving, as the Incarnation, the birthday of Jesus.

I’d like to share my thoughts about these things – informed by my faith as a Catholic, my heritage as a secular Jew, and my vocation as a physicist. They won’t be given with the most important first; I’ve saved the best for last.

ABOUT HANUKKAH (CHANUKKAH¹)

Here’s a brief account of the story behind the verse from First Maccabees quoted above. (For more details, see here.)  The Maccabees had revolted against the Syrian ruler, Antiochus, who had tried to instill Greek values and religion onto the Jews.  And as the Talmud recounts the tale, in their recapture of the Temple and its rededication to the one true God, they found there was oil for the lamps that would only last one day; they filled the lamps and lo, and behold, the oil lasted eight days – a miracle!

The holiday is not one of the major Jewish holidays. In my opinion, it has become more important in recent times as a counterweight to Christmas. Eight candles are lit in the Hanukkah menorah (one for each day the Temple lamps burnt.) And children receive a present each day, including “Chanukah gelt” (money). Latkes (potato pancakes) are also a tradition².

It is a joyous time, celebrating the freedom to worship. And the songs are among the best in the Jewish and Yiddish folk tradition.   One of my favorites is that by the Klezmatic Conservatory Band, Oy Chanukkah;  here are the lyrics.  Note in the last verse, the element of light:

 “Oh, Hanukkah, Oh, Hanukkah,

Come light the menorah

Let’s have a party.

We’ll all dance the hora 

To remind us of days long ago 

One for each night, they shed a sweet light, 

To remind us of days long ago.”

I will concede that there is no great theological significance here.

STRANGE PHYSICS³

There was a young lady named Bright,

Whose speed was far faster than light.

She set out one day

In a relative way,

And returned on the preceding night. Edward Lear? A.H. Buller?

Classical physics treated light as an electromagnetic wave, a linked oscillation of electric and magnetic fields. In the early 20th century Einstein’s explanation of the photo-electric effect gave  light a second personality, that of a particle, a photon. A photon has no mass and travels at the speed of light (which is unremarkable, given that it is light).

Time-dilation enters here: special relativity says that time goes more slowly (stretches out, so-to-speak) as the speed of objects approach the speed of light. This is the basis of the so-called twin paradox: time will go more slowly for a twin traveling close to the speed of light than for his twin on stationary earth, so that when he returns from his voyage, the paradox will have it that he has aged less than his twin (see here). Time dilation is a real effect, manifested in longer decay times of energetic cosmic ray particles, in the very slight slowing down of atomic clocks in orbiting satellites that have to be taken into account in GPS tracking.

TIME DOESN’T EXIST FOR A PHOTON (AND FOR GOD)

From the above one might think at first that time does not pass for a photon.  One could not measure time of  an event for a photon in a reference frame moving at the speed of light. Why? A fundamental assumption of special relativity is that light signals are the ultimately agency of measurements. Since light is the measuring agent, it can’t measure itself. So it’s appropriate to think that a photon does not, in its own frame of reference, experience time. If a photon could be aware, no time would pass from its moment of creation by emission of light to to its annihilation by absorption of light.  Here’s an example: an electron jumping from a high energy level to a lower.  As the electron goes from a high energy level to a lower a photon appears.  That photon can cause another electron in a low energy level to go to a high energy level and the photon disappears in this process. The photon “experiences” no time in this process.

THE THEOLOGY OF LIGHT?

Are there any theological implications in no-time for photons, for light? Well, here’s an off-the-wall thought: we say that there is no time for God,

But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day. 2 Peter 3:8

So the idea that God is light implies also that time does not exist for God. As St. Augustine pointed out, God does not exist IN time; he also said God’s Word is always there, without time, no beginning, no end. And as we see below, God’s Word, our Lord, is light.

Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life. John 8:12 (KJV)

And there are many more.

Now let’s turn to the Gospel of John:

In the beginning was the Word, and the Word was with God, and the Word was God. John 1:1 (KJV)

What is the connection between The Word and light?  The Greek word in the New Testament that translates as “Word” is “λόγος” (“logos”). In addition to the meaning “word”, other general meanings are “principle”, “reason”, “logic.”  Let’s think about the relation between “light” and “logos”.  What do we mean when we say “I see the light!”? We see the reason, the truth, the rationale, the principle in what is said. So “Word” implies both light and reason.  To quote St. Augustine,

The eternal light which is the unchangeable Wisdom of God, by which all things were made, and whom we call the only-begotten Son of God. St. Augustine of Hippo, “The City of God, XI 9”

That tells us that Christ is light, the timeless Word – physics, and theology hang together. And the physicist in me rejoices in the harmony.

Please comment (and criticize).  (By the way, Ahura Mazda, the Zoroastrian God, was embodied in light. So I hope in this reflection I haven’t made a heretical comparison to that early religion.)

NOTES

¹The two different spellings reflect the guttural Ch sound for Chanukkah in Yiddish and the Anglicized H sound.

²Several years ago, the night before Hanukkah, my wife, a cradle Catholic made latkes that would be a prize winner on Chopped.

³For a complete explanation of the dual nature of light, and the historical development of the physics that gave this picture see here.