Home » Solar » Solar Radiation Definition and FAQs

The dictionary defines solar radiation as “energy radiated from the sun in the form of electromagnetic waves, including visible and ultraviolet light and infrared radiation.” That is clear enough, right? Probably not! So, let’s break it down for you.

The sun is a giant hot ball of gas that glows and gives light and heat to our solar system. Its core is in a constant state of nuclear fusion which is what creates the light and heat. Nuclear fusion is a reaction in which multiple nuclei at the atomic level fuse together. This results in both a heavier nucleus and a release of solar energy. It is this solar energy release from the constant activity on the sun that makes up solar radiation, among other things.

As the dictionary definition mentions: “solar radiation comes in many different forms of varying levels of visibility. Visible light, radio waves, x-rays, ultraviolet rays, and heat are all types of solar radiation that the average person is familiar with.”

Q. How far can solar radiation reach?


A. This depends on the type of radiation you are asking about. Certain waves can move further into space than others. Take visible light, for example. We can see stars from as far as 16,300 light years away just with our naked eye. This means that visible light can reach at least 16,300 light years, at least as far as human vision is concerned. X-rays, on the other hand, have a much smaller wavelength and higher energy so they cannot go nearly as far as visible light. The distance also changes based on the medium it is going through. While we can see light through space from thousands of light years away, it does not take too long to dive deep enough into our oceans to get to a point where light cannot reach. Much of the sun’s radiation actually is absorbed, reflected or scattered throughout the atmosphere and never touches us.

Q. Is solar radiation constant?

A. Most definitely not. The sun is in a constant state of flux so the radiation that it puts out, comes in waves. There can be flares and eruptions that shoot large amounts of radiation at random times out into space or sometimes directly at us. Even when the solar activity is fairly constant the rotation and curvature of both the earth and sun mean that there is almost never a straight shot of radiation between the sun and the earth. Some amount of it almost always deflects or is absorbed by our ozone layer. Even in the same physical location the amount of radiation that might be received can change based on time of day, the season, and even the weather.

Q. Is solar radiation harmful?

A. Solar radiation is necessary for life but does have drawbacks. There would be no life on earth without sunlight and heat but it is also common knowledge that too much exposure for humans can lead to illnesses like skin cancer and eye damage. This is mostly due to the ultraviolet radiation that reaches the earth. So, the answer to this question is that it is a double-edged sword for living creatures. For more on this topic, you can read this article.

Q. What is the most dangerous type of solar radiation that can reach us?


A. Ultraviolet or UV radiation is the main form of solar radiation that causes harmful effects on humans. It is divided into three types: UVA, UVB, and UVC. Their order from A to C is an indication of ability to get through the ozone and level of damage they can cause, with A being the most penetrative but also least damaging. Luckily, UVC gets almost completely blocked by the ozone layer so even though it is the most damaging it rarely impacts us. This UV radiation is what our sunblocking materials such as sunscreen and protective eyewear try to block out.

Q. What benefits do we get from solar radiation?


The light and heat radiated by the sun are key to life on our planet, so this is the main benefit. As humans have evolved we have learned how to use these to our advantage. We are especially good at harnessing light energy and converting it to heat or electricity using thermal or photovoltaic solar panels and systems that can take advantage of this energy.

Q. How can sunlight be turned into electricity?


Photovoltaic (PV) solar panels are what is used to collect sunlight and generate electricity. These panels are made up of two layers of semiconducting material, like silicon. The two layers are each given a positive or negative electric charge in order to create an electric field between the two of them. When sunlight hits the panel, the particles of light (called photons) knock electrons free from atoms in the panel. These electrons are then pushed out of the panel and into the grid by the electric field between the two layers of silicon. Electricity is simply a collection of electrons running in a current. This LiveScience article breaks it down nicely.

Q. What is the most important thing to know about solar radiation?

A. Solar radiation is unavoidable and is a fact of life. The term “radiation” may seem scary at first due to the negative connotations of this word being associated with disease, destruction, and even death. But it is important to remember that “to radiate” simply means that one thing is coming out from another. A person can radiate happiness or joy, and that is not scary. So remember that solar radiation is just the different forms of energy that are moving away from the sun as a result of the physical reactions happening within and at its surface.

If you previously knew nothing about solar radiation, hopefully, this has started to answer some of your questions. The sun is not going anywhere anytime soon and neither is the radiation it exudes, so it is important to have an understanding of exactly what that means and how it fits in with your life.