Solar Energy and Life on Earth

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.

Recall that the sun emits energy mainly through X-rays, UV radiation, and infrared light. Gamma rays are not emitted as the sun produces them but converts them into low photons before they are emitted into space.

• Ultraviolet radiation is a type of electromagnetic radiation that makes up about 10% of the total energy emitted from the sun. Its wavelength is shorter than visible light but longer than X-rays. At controlled levels, it's beneficial for humans as it allows for the synthesis of vitamin D, but too much can lead to skin conditions such as sunburn and cancer.

• X-rays are a type of electromagnetic radiation with short wavelengths meaning they have high energy that allows them to pass through most things; this is why doctors can use them to perform X-rays on the body.

• Infrared light is a type of electromagnetic radiation that is longer in wavelength than visible light but shorter than radio waves. Infrared light is essential because it supplies heat to our land and waters. More than half of the sun's emitted rays are in the form of infrared light.

Figure 3: Electromagnetic spectrum illustrated. Wikimedia, NASA.

Advantages of solar energy

Now that we comprehend why solar energy is vital and the types of solar energy, we can go over the advantages of using solar energy.

• Solar energy is a renewable resource that can be replenished or restored within a period of usage. Solar energy will remain an accessible form of energy, unlike fossil fuels, for as long as the sun remains in our sky.

• Solar energy is diverse, as it can generate electricity and heat. Electricity is generated by solar photovoltaics or semiconducting materials such as silicon. In comparison, thermal solar panels collect energy from the sun and convert it into heat.

• Solar energy can provide energy to places without energy grids, power energy satellites in space, and even clean up water.
• Solar energy is also a cleaner form of energy compared to fossil fuels.

• Solar energy is also cleaner than nuclear energy.

Negative impacts of solar energy

Bet you are now thinking if solar energy is so great, why are we still using nuclear power and fossil fuels? Well, the amount of solar energy has increased in recent years.

Despite this, there are still pitfalls of harnessing solar energy, which we will discuss in this section.

There are two ways we can harness solar energy, and that's through either photovoltaic solar Cells or solar thermal plants. The location and the amount of land required can differ depending on which one we use.

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.