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Solar Energy (Start Here)

Solar Cars and Boats
Climate Change Math
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Solar Energy is the glow from our nearest star – the Sun.

We live in the glow of a star named Sol, and we call it Solar Energy

Solar Flares

The Earth is actually 150 million kilometers (93 million miles) from the Sun – which is why the Sun looks rather smaller to us (further away) than it appears in this picture. Note that this is a composite image, for comparison of sizes. Photo coutesy SOHO, the Solar and Helioscopic Observatory. The SOHO site has archived images and lessons. The Solar Dynamics Observatory (SDO) site shows the Sun as it is now, with many ways to access and run data. If you want to know how the sun works, you might start here, where the solar magnetic dynamo is explained.

On a clear day, at the Earth’s surface, we are receiving Solar Power at about 1 kilowatt per square meter (or just over one horsepower per square yard).

“The sun, with its by-products (wind, water, biomass, waves) supplies our planet with 15,000 times more energy per day than humans consume.” -Herman Scheer, Chairman of the World Council on Renewable Energy, June 2006

For most of mankind’s history we have assumed that the Earth we stood upon was the center of the Universe. It is only in the last 400 years that we have gradually learned where we are in Space, roaming the sides of a rotating spherical planet, attracted by gravity to its surface, as that planet follows its Sun in a slow wheel around our galaxy, in a Universe with about 200 billion observable galaxies. Even now, most of us are in the habit of thinking of the Sun as moving across our Blue Sky as the Earth stands still. After all, we don’t feel ourselves moving. Think of the Horses of the Sun, pulling a Blazing Chariot. For a good compilation of Sun legends from around the World, visit: Solar Folklore. According to a Haida story, in the beginning the world was in total darkness…. RAVEN AND THE SUN

Raven and Sun
The strangeness of our Earth’s position in Space compared to our normal sensation of living here is well-reflected in the poem

This rather trippy video is the best I’ve seen for describing our actual path through Space, although it contains several inaccuracies. The word “vortex” does not apply here. And the planets aren’t dragged as in a comet’s tail – sometimes they are actually preceding the Sun through Space. The author appears to be updating as his understanding increases – there is a Part 2.

The Earth makes a spiral path, as it follows the Sun, which is also moving through Space, 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.”
World Sunlight Map

Plants absorb solar energy in a remarkable process called “making with light” – photosynthesis. Plants intercept solar radiation with their leaves, and in that remarkable process, make themselves mostly out of light and water and carbon dioxide. We and other beings rely for our energy on the vegetation produced – that vegetation, “stored” solar energy, is our only source of energy for living. We call it ‘food’ – but really, it is sunlight bound into chemical bonds we later ‘digest’, and run on. We run on sunlight. We are SolarDriven. In a very real sense,

we are creatures of light. In the oceans phytoplankton are the base of marine life. “Like their land-based relatives, phytoplankton require sunlight, water, and nutrients for growth. Chlorophyll is used by plants for photosynthesis, in which sunlight is used as an energy source to fuse water molecules and carbon dioxide into carbohydrates—plant food. Phytoplankton (and land plants) use carbohydrates as “building blocks” to grow; fish and humans consume plants to get these same carbohydrates.” –[from What are Phytoplankton? by David Herring, at NASA’s Earth Observatory site]. A quick but thorough description of photosynthesis and how it arose is found here, at the site.

A green leaf – a photochemical factory binding light energy

Life in the Sea – light-eating plankton

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 day-side, and energy radiated away night-side, 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.

“This spectacular “blue marble” image is the most detailed true-color image of the entire Earth to date. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations of the land surface, oceans, sea ice, and clouds into a seamless, true-color mosaic of every square kilometer (0.386 square mile) of our planet. These images are freely available to educators, scientists, museums, and the public.”

Raven and Sun


Solar radiation peaks in the visible light range (blue) and tapers off into the infra-red. About 42% of the sun’s electromagnetic energy is something we also see with…we call it light. The different colours we see are the result of different wavelengths of light energy reacting with the biochemistry of our eyes. It is a difficult thought to grasp, but true, that colors don’t exist except in our minds. Outside of us, “yellow” and “green” don’t exist…just different wavelengths of radiant energy.

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.

  • Nearly all Solar Energy is what we have always perceived as Light and Heat.
  • 99% of Solar Energy is between 200 and 4000 nanometers in wavelength.
  • Depending on what wavelengths are agreed upon as “visible light” (between 380 and 750 nanometers) about 42% of the sun’s energy is visible light.
  • About 6-7% is in the ultra-violet (ultra = beyond; “beyond”-violet) range. Most of this is shielded by the ozone layer (which appears to be slowly recovering).
  • The rest (just over 50%) we call near infra-red (infra = below; “below”-red). We perceive infra-red radiation as heat. It is the trapping of infra-red radiation going back out into space which is the main cause of global warming.

Spectral distribution curve of incoming Solar Energy

Solar Radiation Curve (as this earlier graph shows, there was thought to be more over-lap with the water vapour and carbon dioxide absorption spectra than later more accurate measurements show there really is.)

series of blogs begins here, at the “Science of Doom” site, called Visualizing Atmospheric Radiation. “This series calculates lots of interesting things about absorption and emission of radiation in the atmosphere.” Having trouble believing “an insignificant trace gas” could affect the working of our planet in this solar system, please see “An Insignificant Trace Gas“.

Solid Introduction to Solar Radiation page has been generously set up by NewPort – there is a good in-depth look at what constitutes solar radiation here. Compare their insolation curve (below) to the one above.

Insolation curve – aka solar irradiance curve

Here it is written that 96.3% of solar irradiance falls between 200 – 2500 nanometers – and this is indeed true – it tails out to 99.9% at 4000 nanometers. Again, the energy from our Sun is predominantly what we have always registered as Heat and Light.

Another great site for understanding Earth’s place in space and the energy that we receive from our Sun is the “Windows to the Universe“ site of the National Earth Sciences Teachers Association. This site has accurate information and good graphics and videos.

Everything radiates everywhere.

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.]

Electromagnetic Radiation, Temperature, Colour, Light

[The “Star Light, Star Bright” section of Amazing Space, an interactive educational site made by the Space Telescope Science Institute for NASA, is experientially well worth the visit…Toast the Robot! “Adjust the temperature of the nuclear-powered blow torch and see how the spectrum of the robot changes as you increase the temperature. Observe where the peak wavelength is at each temperature.”

Toast the Robot!

Visit the Nine Planets Web site to gather facts about the Sun and Earth.
For images of the planets, see the Solar System Simulator at NASA

How the Sun works: (by Solar Radiation on Earth: A quick overview of what happens with incoming solar radiation. From Sun to Earth: Description of solar energy arrival and dispersion

Remote Sensing: “What you can learn from sensors on spacecraft that look inward at the Earth and outward at the planets…”

Solar Energy feeds All of Life on this Planet’s surface.

What is Photosynthesis?

SunLeaf – A peom by Michael Cooke

from a painting by Patricia Brown

Solar Energy causes Winds and Ocean Currents.

Guided Tour on Wind Energy:

This is the famous and best Danish Windpower site. Quite simply, if you want the best education available on the InterNet about Wind Power, go there. For younger children, they also have Wind with Miller. Also, we highly recommend The KidWind Project: where: “… a team of teachers, students, engineers and practitioners [is] exploring the science behind wind energy in classrooms around the US. Our goal is to introduce as many people as possible to the elegance of wind power through hands-on science activities which are challenging, engaging and teach basic science principles.” Solar Tower Power: Build a 5 kilometre wide circular greenhouse, put a 1 kilometre high chimney in the middle, and place a turbine where the heated air rushes up the chimney. Only in Australia, you say…but no, lately interest has shown up in the American sunbelt.

Danish Windpower Site

Ocean Current and Tidal Energy: Peace Initiative, initially designed by Barry Davis, the man who brought you the Avro Arrow and the Bras d’Or Hydrofoil. “The Davis Turbine can be compared in design and output to an ultra-efficient underwater windmill.” “Blue Energy Canada: is commercializing the Davis Hydro Turbine, a technological breakthrough able to generate high-density renewable and emission-free electricity from ocean currents and tides at prices competitive with the cheapest conventional sources of energy today.

Solar Energy heats the world ocean

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 the cold bottom water and the top heated water, and use the upwelling nutrients in floating sea-farms?

History of OTEC and How It works

There are very few companies investing in this currently. Here, a video from Lockheed Martin shows plans for such a facility.

Solar Cars and Boats
Climate Change Math