Take Me Outside: The power of the sun
The house I live in is both heated and powered by the sun. I don’t pay for electricity, thanks to the 16 solar photovoltaic panels on my roof. But why am I writing about solar power in a column that focuses on nature? Because the sun not only makes energy for my house, it also provides the energy that we all depend on for life, and this is a great time of year to appreciate that fact.
As June begins and the Summer Solstice occurs on the 21st, its worth reflecting on the role the sun plays in the natural world, and in our very existence. This month we will receive more sunlight per day than at any other time of the year. The Solstice is known as the longest day, but technically this year there are 11 days that provide 15 hours and 17 minutes of sunlight (on this part of the planet). Compare that with 9 hours and 5 minutes around the Winter Solstice in December (the shortest day) and it inspires you to relish the sun at this time of year.
Spring in New England is a time of great change, one of the most noticeable transformations is the greening of the landscape. Trees, shrubs and herbaceous plants use energy that is stored in their roots to push out new leaves. These tiny leaves, formed last summer, have been dormant and protected as buds during the winter. Leaves are the power generators for the plants. Each is like a miniature solar panel, able to absorb the light of the sun and convert it into useable energy.
I often marvel at common, simple green leaves. Within their cells they are capable of doing something that we need advanced technology to do. When we sit in the sun, we get sunburned. When green plants catch the rays, they make food in the form of glucose.
You may remember learning about photosynthesis in elementary school science class or a more advanced version in high school biology. Yet, this incredible process is worth reviewing. Within the leaves of any green plant are chloroplasts which contain the green pigment chlorophyll. The chlorophyll absorbs light, which triggers a chemical reaction. Sunlight alone does not make the glucose. Many young children can tell you that trees need carbon dioxide (the stuff we exhale) to grow and give us oxygen (the stuff we inhale) in return. These gas exchanges are part of the equation. Add in some water and you’ve got a photosynthetic recipe for food, life, or what I like to think of as pure magic!
The next time you are outside, find a green plant, pick a leaf, crush it up and rub it onto an index card or piece of stiff white paper. You will see the chlorophyll (what moms call “grass stain”) on the paper. Without that chlorophyll, we wouldn’t be alive today. All of the food we eat ultimately comes from plants, which use the sun to make the food. So don’t forget to thank the green plants today.
Now back to the sun. It is our position on the planet that determines how much sun we get at any given time of year. The closer you are to the equator, the more equal the length of day and night, and that doesn’t change throughout the year. As you move toward the poles, the difference in seasonal day length gets more extreme. If you’ve ever been to Alaska during the summer, you have experienced the land of the midnight sun. In the winter it is just the opposite, there is very little or no light up there during December.
The tilt of the earth and how we face the sun, not how close we are to it, determines our seasons and day lengths. The earth is actually further from the sun during our summer, but the Northern Hemisphere is tilted toward the sun creating longer periods of sunlight in this season.
Whether you enjoy sunbathing at the beach, appreciate the longer days of the growing season, or just value the brief summer we have in New Hampshire, take time to savor this season of light and acknowledge the power of the life-giving sun, which we take for granted far too often. Happy Solstice!