Sunset

Amazing colors of a sunset over Mission Beach. Switgard Duesterloh photo.

Mornings are my favorite time of the day and this one was truly spectacular. Sometimes I can adjust my work hours so that I can get in a run before starting work. Today was one such day. On my first loop around Lake Gertrude at Abercrombie Park the sun just climbed over the horizon as a big red ball. The ocean lay serenely and on its surface it seemed like a swirl of colors from red to pink, purple to gray competed with shadows and highlights to paint a surreal array. In the forest, the red light mixed with the greens and browns of moss and spruce trees, creating a living chapel filled with the chittering sounds of squirrels.

While these images moved my soul, I thought about how this natural magic contrasted with and at the same time fueled my interest and passion for science. If you ask scientists in my field, ocean science, about their original motivation to devote their professional lives to science, it often comes down to formative experiences and memories of activities on or near the ocean. There is one thing about the ocean that is irresistable to the curious mind: As we gaze upon the surface, we can only wonder about what is beneath, but without instruments and technology we can’t see.

On my second loop around the lake the sun had climbed off the surface of the ocean and stood a bit higher in the sky. It was now white and blinding and I had to squint to see where I put my feet.

“To those of us who live on earth, the most important astronomical object by far is the sun. It provides light and warmth. Its motions through our sky cause day and night, the passage of the seasons, and earth’s varied climates,” it said on a Weber University astronomy website. Technically, the sun does not move through our sky, but rather the earth moves through its sky. That is because the sun is so much bigger and has so much more gravity that the earth travels around the sun, not the other way around. One could say that “sunrise” is a misleading term, because on my second loop around Lake Gertrude the sun was still in the same place, but the earth had rotated enough that I could now see it fully and its rays were hitting me more directly.

Why is the morning light red? Because it has traveled a longer way. Let me explain: White light is a mix of all the colors in the rainbow. In fact, when you look at a rainbow, the water droplets in the air have broken up the white light into its fragments, thus showing all of its colors. Each color has a different wavelength. Small wavelength means high energy and large wavelength has less energy.\

As light travels through the atmosphere many tiny particles of dust and pollution get in the way. Because of its properties, blue light is more likely to get scattered and what is left is red and yellow light. Thus, when we look at sunlight at a shallow angleduring sunrise and sunset, which means it has travelled a longer way through the atmosphere, it looks red or orange. After a volcanic eruption or a forest fire the sky often also looks red and orange. In those cases there are even more tiny particles in the atmosphere scattering the blue light and sometimes making the sky look red even during the day.

As noon approaches the sun now stands high in the sky, its rays travel a more direct and shorter path and we see the full spectrum of light, which is why the sun looks white. A lot of blue light scatters in all directions and that is why the sky looks blue.

If you take a flashlight or laser pointer and shine it directly at a surface, the area of light is small and round. If you tilt the light source, the area of light gets oval and the light less intense. The same amount of light energy is spread out over a larger area. In the morning, the sun rays hit us at an angle and the energy is spread out more, giving less warmth to any one place. That is why it is still cold in the morning but the noon sun has more power to warm things up.

Last Tuesday after a busy day I took my dog to the park and while she romped with other dogs I sat on a bench in the late afternoon sun. There were two ladies who talked about how the last winter had made them miss the sun so much. Our bodies need the full spectrum of the sun to make vitamin D and certain beta-endorphins, which help you feel happier. The lack of light in Alaska’s winter affects some people making them feel sad or depressed.

One of the ladies was planning to break up this winter with a trip to Cancun, where the sunrays are more direct and have more energy. If you can’t go to a tropical paradise, try to make the best of every day by going outside during the lunch hours, using the full spectrum light bulbs inside and keeping your body balanced with lots of exercise and healthy foods. Until then, make sure to enjoy the amazing sunrises this fall has in abundance.

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