Sun Cult: Observing Nature's Cycles

Part 1: Why our ancestors revered the sun—and perhaps we should too

Fall is a time of change for all living creatures. Bears stuff themselves with berries, mushrooms, nuts and anything they can find in the trash in preparation for hibernation. Girls dress in earthy tones and cozy up under a throw with lattes and books. The season’s headliner, however, is without a doubt the mesmerizing show put on by trees: aspen shimmer in their golden-yellow foliage, dogwood turns inexplicably purple, and maples blaze like a bonfire against the bright, clear autumn sky. 

People tend to attribute seasonal metamorphoses like the changing colors of the leaves to the shift in temperature. And, of course, that plays a large role in the seasonal shifts. But the underlying reason behind all these phenomena is actually light. Regardless of all other environmental factors, trees still change the colors of their wardrobe, even on an unusually warm and dry autumn. The transformation is governed by not by the chilly temperatures or rains, but by the shifting light spectrum.

Remember from physics, that what we perceive as a “white” light is really a rainbow of different colors? From the short-wave, invisible ultraviolet (or UV) to eye-detectable violet, blue, green, yellow, orange and red, followed by the long-wave unseen infrared waves that we sense as heat. This invisible rainbow is the key to the fall’s spectacular color display. 

As the days get shorter and less energy from the sun is available for photosynthesis, trees try to absorb the maximum amount of light by making new, specialized pigments. Chlorophyll, the molecule that gives plants their emerald color, absorbs the blue and a little bit of the orange and red spectrum. There is so much of this green pigment in plants that it masks other ever-present light-absorbing molecules—carotenoids. As the amount of daylight decreases, chlorophyll production slows down and eventually stops, and the carotenoids begin to reveal their autumnal gold.

Another contributor to nature’s fall palette is anthocyanin which creates beautiful red and purple shades. Anthocyanin absorbs the green parts of the sun’s spectrum which other pigments cannot use, helping capture those last bits of solar energy. The light is what makes plants grow by allowing them to condense the carbon from the atmosphere into solid wood and leaves. And the light is the reason why the trees don’t “work” in the winter.

Observing the seasons

Light surrounds us, yet we rarely see it. But if you pay attention, you will notice the subtle changes that occur throughout the year.

If you watch the sunrise and sunset every day, as I do, you will see that the place on the horizon where the sun emerges and retreats shifts every day. Depending on how far north you live, you may be stunned by how fast it moves—you may have to change your sunrise viewing spot almost daily! You will also notice that the sun does not get as high up in the sky in the winter as it did in the hot summer months. The arc that the sun makes in the sky gets smaller and the time the fiery orb takes to traverse the length of it decreases.

You can also observe the quality of the light shift. There is a higher proportion of UV and blue light wavelengths during the summer months—simply because those shorter waves scatter more in the atmosphere. When the sun is higher up in the sky, hitting the Earth at close to a 90-degree angle, those short-wave photons are able to take the shortest path to the Earth, without getting side-tracked by the particles in the atmosphere (aka clouds). In the fall and winter, however, the sun sits lower above the horizon, which means it has to slice through the atmosphere at an angle. This way, more UV and blue light gets scattered, and what you get is a higher proportion of the soft-white, yellowish light.  

We often get seasonal depression in the cold months. The lack of light changes the amount of serotonin and melatonin produced in the brain. When these chemicals are not balanced, we experience sadness, depression and sleep disturbances characterized by seasonal affective disorder (SAD). The cure for SAD is bright light therapy, which works with up to 90% efficiency. This simple and brilliant solution shows just how much our physiology and psychology are affected by our light environment. Although we are not trees, we too get our energy and motivation from the sun.

And just like trees, we also have pigments that absorb sunlight. They serve a different purpose than the ones in plants but they are no less important. Light-absorbing pigments in our body act as mediators for regulating our hormones, mood, energy and sleep. Light receptors are located in our eyes (otherwise, how would we see?), our skin (the melanin that gives skin its color and produces vitamin D), and even in some unexpected places, like the brain, certain glands and even sperm cells. There is strong evidence that light even regulates our gut microbiota and appetite.

This makes a lot of sense: in the winter, the low light environment is correlated with lower access to food. Our metabolism slows down to conserve energy. We switch from a high-carb diet (evolutionarily speaking, high-carbohydrate foods like fruit were only available in the summer months) to animal fat and protein—that poor turkey or pig, fattened on summer’s bounty, that would get sacrificed to supplement the diminishing amounts of plant-based foods as the winter went on.

Fasting practices exist in many cultures around the scarcest times of the year. And while these traditions were likely motivated simply by lack of food, they actually benefitted our ancestors’ health, by allowing the body to kick-start the process of autophagy, which recycles damaged cells and even destroys some pathogens. Over millions of years of living in tune with the seasonal changes, it would be surprising if our bodies did not develop physiological responses to the environmental cues that accompany those changes.

Celebrating the seasons

In today’s world, we don’t have to worry about seasonal food shortages, cold temperatures, and extended hours of darkness. We can create a comfortable environment for ourselves all year long. But our bodies still have that genetic memory that gets activated every fall. In that sense, we are no different from our ancestors.

Ancient cultures had many rituals around the seasonal movements of the sun. People who lived here long before us, sat there just like me, watching the sun rise and fall, day after day. They knew its precise position and built megalithic structures around it. It is easy to discard those practices as superstitious pagan beliefs, but I think there was more to it. Our predecessors were much more in tune with these cycles and conscious of the biological wisdom of seasonal adaptation. 

All of nature follows the Sun Cult. And maybe should we. Maybe slowing down, and embracing the lull of the winter is what we are supposed to do. To take these moments to rest, to hibernate, to recycle dead cells through fasting, so that we can come back with renewed enthusiasm in the spring, ready to start growing new things when the sun returns with its powerful force.