12 minute read
the lens of light
Light is one of the most fascinating phenomena in science, enthralling thinkers and scholars from Euclid to Einstein. Its complexity has posed many important questions, and optics continues to be an important field in contemporary physics. Conversely, understanding the nature of light also changes the way we see everything else. We’ve invited some of our friends to share some different ways of looking at—and through—the same light.
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THE FIRST FLASH OF LIGHT IN A DARK UNIVERSE
Molly MacRae
Molly is a third year Physicist at Jesus. She currently spends her free time wandering through fields, eating marmalade toast, and shielding her house plants from two hungry cats.
This is how the Bible begins the story of our universe in Genesis—God calls a flash of light into the darkness. As we know it, our universe began as a plasma, far too hot and dense for atoms to form, and dark to an observer. Photons of light bouncing around inside were continuously absorbed and scattered and given no opportunity to escape. At around 300,000 years old, the universe had cooled and expanded enough for recombination: protons, neutrons and electrons could combine to form the first hydrogen and helium atoms. Light photons could finally travel freely throughout the vacuum. The first thing that would have been seen of our universe is a blinding flash of light. It would have glowed like a vast star as it continued expanding. Like the rest of the universe, this light was spread, and eventually stretched into microwaves, and this is how we observe it today, as Cosmic Microwave Background. When tuning a radio, 1% of the noise you hear between stations is this CMB—the remnants of initial flashes from the early universe.
Almost everything we now know about the universe beyond our planet has been carried to us by light. Slight fluctuations in the CMB are potentially the seeds of higher density that allowed the first stars and galaxies to be born. When you gaze up at a clear night sky you are not only seeing a glistening display of ancient starlight, but a map of the entire history of our visible universe.
Reading on in the Genesis story of creation, it is difficult not to notice how concurrently it follows the order we observe in science today, despite the limited scientific knowledge of the writer. This is unsurprising for Christians, who believe the words of the Bible were, though written by people in their time, inspired by God.
Our research in science can perhaps tell us everything that happened since the beginning of time, but we fall silent when we are asked the question why. It is the same silence that often follows moments gazing up at the night sky. Our awe at the beauty of our universe and our purpose in it, and the reason we feel this awe at all, seemingly cannot be explained by science itself.
Looking at Christianity, it’s sometimes easy to wonder about the complete mystery of how God could possibly send his son into the world to conquer death for us. But in these moments of awe, when I remember that it is the same God who spoke light into existence, I feel that perhaps this is not such a mystery at all.
ILLUMINATION; REVELATION
Jacob Mercer
Jacob is a third year at Worcester studying Mathematics and Statistics. He loves to spend his time stuck into a good book, making music, or pretending he’s doing his degree by doing today’s puzzles in the newspaper.
Illumination; revelation. The moment when you see things in colour, where once they were dim. To me, the joy of doing mathematics is the journey from unknowing to knowing; darkness to light.
When I’m doing maths, I often feel like an excitable child, running through an unfamiliar forest. As my mind races to recall theorems that might lead the way to a solution, so too do I race along the wooded path, urged by curiosity to see where it leads. I often find myself in mundane beige libraries on mundane grey days, scribbling down line after line of strange greeks symbols so frantically and excitedly that my heart beats a little faster. Like the banquet held for the prodigal son, the time is spent in confusion and unknowing highlights the elation of the path to knowing.
The notable mathematician Andrew Wiles describes the sensation like this: “You enter the first room of the mansion and it’s completely dark. You stumble around bumping into the furniture, but gradually you learn where each piece of furniture is. Finally, after six months or so, you find the light switch, you turn it on, and suddenly it’s all illuminated. You can see exactly where you were.”
However these affections aren’t exclusive to my academic curiosity. I reminisce fondly when, as a new Christian, God revealed himself as I read the Bible—but unlike the realisation and elation of understanding in mathematics when I solve a problem or prove a theorem, revelation from God is walking out of a dim mine on a bright day into dazzling brilliance. It may take time for our eyes to see in the presence of this greater light, but we do not draw away, because once we have seen this light, to turn back is darkness and His sunlight warms us.
So I thank God that He has let me taste both such lights. After all, we study in an institution crowned by the motto “Dominus Illuminatio Mea”. The Lord is my light.
AFFECT AND AFFECTIONS
Alvin Tan
Alvin has recently graduated from Queen’s with a degree in Psychology and Linguistics. He is already experiencing the wistful nostalgia of not being in Oxford, and would love to be back soon.
When wintertime rolls around and the nights grow longer, around 1 in 10 to 1 in 100 people will begin to experience depressive symptoms such as changes in mood or sleeping habits. This is known as Seasonal Affective Disorder, which has the unfortunately fitting acronym SAD. It also seems to be more prevalent at higher latitudes, which suggests that it is related to daylight hours. Perhaps you have experienced this yourself, or know someone who has.
SAD seems to be the black sheep of psychological conditions—psychologists were initially sceptical of its validity as a syndrome, and even now it is typically classified as a seasonal variant of other mood disorders. Its intervention options also sound somewhat bizarre and verging on the homeopathic—for example, the symptoms of SAD seem to be alleviated by negative ion treatment. The most common and most effective treatment, however, is bright light therapy. This involves the individual being exposed to a bright light (from a light box) soon after waking for half an hour to two hours. Indeed, since SAD appears to be related to daylight, a light-based treatment shouldn’t be surprising.
What is somewhat surprising is the fact that we don’t really know what the biological processes that lead to SAD are. A common theory is that SAD is related to a disruption of the body’s normal circadian rhythms, which are internal processes that regulate the cycle between sleep and wakefulness. The evidence for this is mixed, however, as treatments for SAD don’t seem to reduce any circadian disturbances. There is some promising recent work on the relationship between SAD and the neurotransmitter serotonin, but we will have to wait for more evidence to determine the veracity of that theory.
What SAD does demonstrate is the reliance that humans have on light, not solely for its tangible functions, but also for its implications on our well-being. Something in the basal part of our brain relies on light, like a sort of affective phototropism. In some ways, this is akin to what philosopher Tim Crane calls the “religious impulse”, or an urging towards the transcendent. It seems that this impulse is fundamental to the human condition; what differs among humans is the manner in which they address or satisfy that impulse.
Perhaps this is indicative of the design pattern for humans. Indeed, the very first page of the Bible tells us that we were made in reference to the transcendent God (Gen 1:27). If this is truly the case, then our lives are most abundant and fulfilled when we live in accordance to that transcendent order. Much as light boxes pale in comparison with the splendour and warmth of the summer sun, so do alternative spiritualities fail to meet that innate impulse. Then, it is only by placing our affections on the Son and basking in his light that we can experience the fullness of what it means to be human.
UNDERSTANDING PARADOX
Emily Kilgour
Emily studied Physics at Teddy Hall and is from Glasgow. She loves stargazing, owls and exploring the lochs and glens. She has just graduated and is excited to spend this year back in Oxford as a church apprentice.
What is light? It’s a simple question, given light is something we encounter every day. Yet, it has puzzled people for millennia.
In some experiments, light seems to travel through space like water waves over the sea. In other cases, it speeds along in tiny packet-like particles of energy called photons. So, which is it? Wave or particle? Weirdly, both pictures describe light’s nature, a concept called wave-particle duality. Though it seems paradoxical, the two ideas are held together because the reality is more complex than our limited attempts to understand from only one perspective.
The Christian life is full of confusing paradoxes. How could Jesus be both fully human and fully divine? If God is sovereign over everything, how can we be responsible for our own sin? How can God be both knowable and mysterious? Even the Gospel is a paradox of sorts; the one who Himself is Life loved us enough to die, so we can be saved if we repent and trust in Him.
The Bible affirms both sides of these paradoxes to be true, though they seem contradictory. We know the one who tells us these things is perfectly good, loving and consistent. Therefore, we can trust that when we don’t fully comprehend, it is not because God is wrong. It’s because we don’t have the whole picture. “For as the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts,” declares the Lord (Isa 55:9 ESV).
It is wonderfully good to study and delight in God’s vast, intricate and beautiful creation. He wants us to increase in our understanding of Him and His love for us. But, part of growing in humility is recognising that there will be things we never fully understand in this life and may grapple with until we see Him face to face, no longer in part, but in full. For now, Proverbs 3:5–6 says, “trust in the Lord with all your heart and do not lean on your own understanding. In all your ways acknowledge him, and he will make straight your paths.” When we can’t reconcile the paradoxes alone, we choose to cling to the one who Himself is Truth, and trust.
I am amazed that no matter how much I study it, I can never get over light’s beauty. The vivid colours of the rainbow after the storm. The evening Scottish sunlight shining through the trees outside my window. A sky full of stars whose light has travelled for hundreds of years to reach us. The laws of refraction explain the sun reddening as it sinks towards the horizon, but cannot calculate the awe I feel watching a sunset. We won’t always fully understand. But we can marvel at the view which glorifies the one who created it all.
LIGHT AND TIME
Kieran Moore
Kieran is a third year Physicist at Somerville college. He enjoys playing the clarinet and ultimate frisbee. In lockdown he has re-read the Narnia, Hunger Games, and Harry Potter books, all of which may be more real than ideal harmonic oscillators.
On a clear night, as you look up at the stars, what you are doing is looking back in time. The speed of light is a universal speed limit, and a fundamental constant in physics—an unchanging 300,000 km/s in the vacuum of space. This large but finite speed means that the light we see in the night sky today left stars hundreds of years ago. Yet, if we could see microwaves, there would be a dim smear all over the night sky. This is the famous “Cosmic Microwave Background” (CMB), ancient photons arriving after a journey from just 380,000 years after the Big Bang. When they left, they were emitted from a hot plasma at visible wavelengths, but the expansion of the universe red-shifted them. Now, therefore, they are microwaves corresponding to a temperature of just 2.7 K. This timescale (~13 billion years) is clearly vast, but amazingly, the Bible has claims of certainty about eternity.
Often when searching for a purpose, we look to things that will last. Yet ultimately, nothing in this world endures forever. In contrast, the Bible claims that we can influence what happens to us for eternity. Something that lasts forever is surely worth much more than things that decay. Jesus makes this point clearly, saying:
So how can we get “treasure in heaven”? If we are only on earth for a finite amount of time, how can we earn something of infinite value. Wonderfully, as Peter explains, we don’t have to earn it, indeed we can’t:
You can’t work your way to an inheritance; it’s given to you. This is the central claim of the Christian faith. Though we are unworthy, by God’s infinite grace, we can be welcomed into heaven, an eternal inheritance, and a living hope. How? By the sacrifice of Jesus Christ on the cross, his resurrection, and by placing our faith and hearts in him, that he will return and raise us, and give us treasure we don’t deserve. The CMB might be 13 billion years old. The heat death of the universe might take up to 10100 years to work itself out. But the promise of God is that we can be raised to new life and live forever in glorious relationship with him. Isn’t that something worth checking out?
