Solar Energy

Oh, island in the sun
Willed to me by my father's hand
All my days I will sing in praise
Of your forest, waters, your shining sand - Harry Belafonte
      

   Think of the Horses of the Sun, pulling a Blazing Chariot. For a good compilation of Sun legends from around the World, visit:

    The Earth makes a spiral path, as it follows the Sun, which is also moving through Space, towards the constellation of Hercules, leading with our South pole in an anti-clockwise motion.

    Because our planet is spinning off-tilt (by 23-1/2 degrees) to its path around the Sun, and because our annual orbit around the Sun is also elliptical, different parts of the Earth's surface receive varying amounts of Solar Energy throughout our days and year. These differences in energy are evident each day as morning, noon, and night; and throughout the year as our Seasons. It is the difference in light energy received that determines the life possibilities for plants and other beings. Each time we orbit the sun, spinning at a tilt, as we are, we repeat the cycles of seasonal life.

   Please check out the sunlight the world is receiving today, at the World Sunlight Map, which uses real-time satellite data to provide various map projections of our changeful planet. Or, as they say it: "Watch the sun rise and set all over the world on this real-time, computer-generated illustration of the earth's patterns of sunlight, darkness, and cloud cover based on current weather satellite data."

    Our thin layer of atmospheric gases deflects and scatters to some extent direct solar radiant energy. Clouds of water vapour reflect some of it. Nevertheless, as each part of the planet turns toward the Sun, on a 'sunny' day roughly 800 -1000 watts of power per square metre are received at ground [1 horsepower = 746 watts] for many hours at a time. This warms the surface of our planet, mostly ocean. Ocean and air currents further transport warmth from the equator to the poles.

    At each point on the planet's surface, solar energy taken on during the day is re-radiated into Space at night. After "sunset" that freshly turned surface of planet is now warmer that anything in Space surrounding it, and must necessarily radiate away its heat. "The coldest hour is just before the dawn". Turning into the Sun's radiation each morning we again take on more solar energy. The Sun is always shining, and the Earth is always spinning. Constantly, half of the Earth is receiving direct solar radiation, and half is facing into Space and radiating energy away. As long as there is a balance of energy received on dayside, and energy radiated away nightside, we have our normal climates through the seasonal energy wobbles.

  But the way our atmosphere plays with incoming solar radiation and outgoing infrared radiation became apparent to us only after long and repeated looks at the Greenhouse Effect. For a history and the current knowledge of The Carbon Dioxide Greenhouse Effect....which led to the discovery of Global Warming...

    Concerns about Climate Change (a.k.a. Global Heating) arose because pollution from our combustion activites is changing the composition of the gases in our atmosphere. Some of these new and/or increased gases absorb the out-going infra-red radiation at night-side, keeping that energy in our atmosphere, from where it can re-emit to Earth, rather than away into Space.

   During the night we are getting a small back-glow of radiant energy from those gases. The current estimate right now of this radiative forcing is about 2.5 watts per square metre. While this may not seem like a like a lot, it IS incremental. It appears until now that the oceans warming, and the ice melting, as well as a fair bit of industrial haze providing Global Dimming, have kept us largely unaware of what increased heat retention on this planet might mean. Even then, the numbers are as relentless as the Sun - we've ironically bought some cooling with our direct haze, so that a person can talk about a net forcing of 1.7 watts; but like a juggler, we've got to keep throwing those sulphate and particulate matter balls into the air daily to benefit from their shade and reflectivity (albedo)...and acid rain and particulate in lungs are among many side effects of air pollution. Because of our growing thicker greenhouse blanket, an increase of the energy retained on our planet is taking place - and at a rate of change this planet has never seen before.

   To study this very serious pollution problem we've got with our own waste gases, and to help various national jurisdictions on this single planet's surface to come together on not over-heating our only planet, we have formed, from the best of our Scientists, from all over this world, the Intergovernmental Panel on Climate Change.

   Although water vapour is the greatest volume greenhouse gas, by far the most bountiful of the gases produced by human activities is Carbon Dioxide, followed by Methane. These absorb radiant energy at wavelengths that water vapour doesn't. Right now our planet's surface temperature (including atmospheric and ocean temperature) is rising. This will have many ramifications, not the least of which will likely be methane gas released from the melting gas hydrates now trapped in permafrost. ("Even the permafrost reservoir is on the order of hundreds of gigatons, not much smaller than the total amount of carbon in the terrestrial biosphere".) Methane has a much higher greenhouse effect than Carbon Dioxide per moleclule, about 25 times as much. Higher temperatures and changing rainfall patterns will affect plants, upon which we rely for food. These are vast changes we have intitiated, mostly by being the number of us that we are, burning fossil fuels as much as we do. We might call it Climate Change, but actually, it's Planet Change, and we're doing it!

   Atmospherically, the palette of change contains the absorption spectra of various gases. These are some common gases, their absorption bands and windows. A very clear writer about greenhouse gas windows and energy absorption appears here, showing how CO2 fills in an important heat-releasing window in the atmosphere, tipping the balance.

   Al Gore has written the easiest-to-digest compilation of all the planet changes we are initiating by burning fossil fuels and forests in such vast quantities. Please see his website: http://www.read-the-truth.com/ for a checklist of mitigating actions each of us can assume, as well as parts of his presentation. Read the book, see the movie, watch the trailer here.

    Because the electromagnetic spectrum is so vast, and the visible band-width such a small part of the electromagnetic spectrum, the error has often been made that visible light can only be a small part of total solar energy (perhaps 5% at most) and that solar energy is some mysterious wavelength energy. 99% of Solar Energy is between 200 and 4000 nanometers in wavelength. In reality, almost all of solar energy is what we've always perceived as light and heat

    Depending on what wavelengths are agreed upon as “visible light” (between 380 and 750 nanometers) about 42% of the sun’s energy is in our visible light range.

    We, as human beings, at our temperature, about 300 Kelvin, emit radiation in the lower "infra-red" range. As does our planet. Were it not for greenhouse gases, our planet's surface temperature would average about 255 Kelvin.

    Our Sun is emitting energy at the predominant 'wavelengths' it does because its outer gases are around 5800 Kelvin in temperature. [Although gravity-driven nuclear fusion reactions deep in the Sun's core provide the energy for heating its outer gases, "solar energy" as received by us is the electromagnetic energy (light) radiating from the (considerably cooler) glowing gases at the Sun's outer layer.] 

    The Sea is a natural collector of solar energy, and its floor is nutrient-rich (big fish eats little fishes, dies, and sinks to the bottom). Why not pump that water up, with electricity made from the temperature difference between bottom and top, and use the upwelling nutrients in sea-farms?