Does Solar Energy Come From the Sun?

I bet you have always wondered about the source of energy in the solar system. Every day, the Sun provides the Earth with enough energy to power our activities. But where does it come from? Is it really sustainable?

The answer to these questions is a resounding ‘Yes!’ Energy comes from the Sun and it’s sustainable. The trick is to find the right way to harness it which doesn’t deplete our natural resources. So let’s look at the various sources of energy one by one and understand where they come from.

Thermal Energy

Thermal energy is generated when heat is transferred from one object to another. The classic example is when you put a hot piece of metal in contact with a cold piece of metal. They will slowly come together and transfer heat from one to another. This is why your oven heats up your kitchen when you bake something in it!

If we examine the surface of the Sun, we can see that it is covered in tiny hotspots where the temperature can reach many millions of degrees. Theoretically, anything that is hot enough can be made to release thermal energy by simply bringing it in contact with something else. In reality, this process is inefficient as so much energy is lost through conduction (heat transfer through the surrounding medium). Nevertheless, thermal energy is the most prevalent source of energy in the Solar System. It is released during the day as the Sun heats up and, at night, absorbed as the Sun cools down. This is why your room feels cold when you step out of the shower and why your home heats up during the day (and conversely why it gets cool at night).

Photoelectric Energy

Photoelectric energy is created when light is absorbed by a material and then converted into electrical energy. This is similar to the way charge is collected by a photovoltaic cell when exposed to light. These days, many scientists are looking into the use of nanotechnology to improve the efficiency of solar energy collection. The problem with this approach is the additional manufacturing steps that are required to scale up its use. Nevertheless, for large-scale energy production, photoelectricity is still the best option available. The next best thing is a hybrid solar system that uses both thermal and photoelectric energy sources. This reduces your dependency on fossil fuels and minimizes the impact on the environment.

Wind Energy

Wind energy is essentially kinetic energy. This means that it is derived from the motion of air. The physics behind wind energy are very similar to those of thermal energy. When air is in motion, it tends to flow toward the object which occupies a higher height. In other words, the higher you build your windmill, the more energy it will produce. This is why tall buildings (skyscrapers) often get their name. They often act as giant windmills and use their height to generate power.

On a smaller scale, you can use the kinetic energy of the wind to pump water. This is how most windmills worked back in the day. They were also used to drive mills to fabricate cloth and various other products. These days, we often use wind energy to power devices that help us remain connected to the Internet. While these seem like useless applications, at least they allow us to conserve energy.

Radioactive Energy

Radioactive energy is produced by the decay of certain elements and it can be easily manipulated with the right equipment. Uranium is the most stable source of nuclear energy with a half-life of 4.47 billion years. A more modern discovery is Radionuclides, which are minerals that contain radioactive isotopes. These isotopes have a very short half-life and can be used to create energy through nuclear fission (a chemical reaction which splits uranium atoms).

Nuclear fission was first used to generate power in a commercial manner in the 1950s. Since then, its popularity has grown immensely as nations around the world have sought to harness this clean and renewable energy source. As with any other form of energy, its beneficial effects are also related to the scale at which it is used. Small-scale tests have proven its efficiency. However, in terms of mass-producing energy, it is not feasible to do so.

Surface Tension Energy

Surface tension energy is generated when a liquid is placed in a container and some of its molecules are spilt over the surface of the container. This liquid has high surface tension which causes it to behave almost like a solid. For this reason, it is also known as a ‘liquid metal’. The most famous example of surface tension energy is in the form of oil which separates into a liquid layer on the surface of water. This is how we get extremely thin layers of oil on water (which can be easily seen with the naked eye).

When light shines on the surface of oil, it is reflected and refracted in interesting ways because of the oil’s high surface tension. This is why viewing angles of light and shadows are affected when it enters the oil. The result is highly diffuse reflected light. The fact that it is diffuse is useful as it acts like a solar filter and reduces the intensity of light that enters the eyes of the observer.

Other Sources Of Energy

All of the above sources of energy (with the exception of magnetic energy) require additional energy inputs in the form of fuel to operate. However, there are other sources of energy which are used to generate electricity that are not mentioned above. For example, gravitational energy is the energy possessed by an object as a result of its mass. It is derived from objects with large mass (large objects contain more gravitational energy than small objects).

In theory, anything with a large mass will possess gravitational energy. One of the best applications of this energy is in space where rocket engines are used to move massive spacecraft. Astronauts onboard these vehicles harness this energy to propel them into orbit.

Another source of energy is radiant energy. This is similar to thermal energy in that it is also generated by the process of heat. However, radiant energy is not affected by the medium which it is transferred through. This means that it will travel in straight lines and cannot be dissipated through conduction. It is quite a common source of energy in the universe and it is used to power things like lightbulbs. 

At the end of the day, it is a question of how much energy you want to consume. If you don’t need much, you can use the above sources of energy to supplement your existing primary energy sources. This would reduce your dependency on fossil fuels and allow you to have a cleaner environment.

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