Solar Energy and Life on Earth

What do you see when you look up at the sky in the morning? Birds? Clouds? Perhaps the sun? Well, you may see all three, but the sun rises and sets steadily every day. No matter where we are located, we have all seen the sun. The sun is so important that it has been observed by astronomers, scientists, and researchers for generations. At one point, it even spanned a war between churches and astronomers like Galileo, and out of that ordeal, we gained a now widely accepted theory of the sun being the center of our solar system. With a title like that, the sun must undoubtedly be a star! Well, it is physically a star and performs many functions, like providing solar energy and life on earth, which makes it deserving of its star-studded title.

Solar energy and life on earth overview

Solar energy is made by nuclear fusion that occurs in the sun. Nuclear fusion happens when the protons of hydrogen (H) atoms collide rapidly and combine to create a helium (He) atom.

Light and energy from the sun mostly travel through X-rays, gamma rays, ultraviolet radiation (UV), and infrared. X-rays, gamma rays, and UV light are high-frequency light mainly absorbed by the earth's atmosphere. Almost all the heat we receive on earth is in the form of infrared light.

Light emitted from the sun is essential to survival as it creates "a greenhouse effect". When we think of the greenhouse effect, we think of global warming, but the greenhouse effect is essentially just heat caused by infrared, UV, and visible light radiated from the sun. The heat from these waves makes the earth warm enough to sustain life.

Around 30% of solar energy on earth is reflected in space, and the rest is absorbed into the earth's surface and atmosphere. The solar energy or radiation heats the earth's surface and, as it rises through the atmosphere, it's trapped by greenhouse gases such as carbon dioxide (\(CO_2\)) and methane (\(CH_4\)).

Figure 1: Greenhouse effect illustrated. Wikimedia, EPA.

Importance of the sun for life on earth

Now that we understand what solar energy is and how it relates to the sun and life on earth, we can go over how the sun sustains life on earth.

The sun can provide heat that warms the planet through the greenhouse effect. Solar energy can also be used by living organisms such as Plants to synthesize nutrients in the form of glucose. Primary producers or autotrophs can make their food through Photosynthesis and give other organisms energy through consumption.

The sun also provides us with solar energy, which is a renewable resource.

Solar energy can be harvested by panels or Cells and converted into usable energy in electricity and heat.

The sun also sustains life by driving our seasons, climate, weather, and ocean currents!

• The earth rotating with a tilted axis around the sun provides us with our seasons.

• Solar energy warms the air masses causing climate and weather changes.

• Ocean currents result from global wind patterns fueled by solar energy.

Figure 2: The sun powers processes likephotosynthesis. Daniela Lin, Study Smarter Originals.

Types of energy life receive from the sun

After understanding the sun's role in sustaining life on earth, we need to go over the types of energy the sun emits in detail.

The sun provides two main types of energy, in the form of light and heat. Generally, we call electromagnetic radiation produced by the sun solar radiation. Solar radiation can be converted into valuable energy, including heat and electricity, that can power our planet. Energy from the sun comes from nuclear fusion or when hydrogen atoms are converted into helium. This process releases energy in the form of electromagnetic waves.

The estimate for photovoltaic panels is 3.5 to 10 acres per megawatt and around 4 to 16.5 acres per megawatt for thermal ones. Solar facilities also can't share the land with agricultural uses like other forms of energy. Some solutions to this include building commercial-size photovoltaic plants and using contaminated land or other areas where habitat loss is less of a concern.

Water is required for cooling when we manufacture solar energy panels. The amount of water used depends on the design, location, and type of system used. We can use dry-cooling technology to minimize the amount of water utilized, but it leads to lower efficiency rates, significantly above temperatures of 100 degrees Fahrenheit. This is a problem because many regions in the U.S. that need alternative forms of energy the most are in the driest climates.

The chemicals used to produce solar energy plants can also be hazardous.

Although solar energy is not associated with global warming emissions, manufacturing photovoltaic and thermal panels is. Most problems aren't related to solar energy usage but the material we use to convert energy into electricity and heat. Installation, manufacturing, maintenance, etc., cause an average of 0.07 and 0.18 pounds of carbon dioxide per kilowatt-hour.

Overall, as our technology implementation improves, we should see higher usage of renewable energy, such as solar energy. The sun is an essential star in our lives and provides us with many forms of energy, therefore is studied closely by many scientists and researchers.