The sun plays an important role for us on Earth. It provides the planet and everything on it with important factors such as light and heat. But what is solar radiation, the spectrum of sunlight, how does all this affect us and the global climate as a whole?
What is solar radiation?
Bad thoughts usually come to mind when you think of the word "radiation". But solar radiation is actually a very good thing - it's sunlight! Every living being on Earth depends on him. It is necessary for survival, warms the planet, provides food for plants.
Solar radiation is all the light and energy that comes from the sun, and there are many different forms of it. In the electromagnetic spectrum, different types of light waves emitted by the sun are distinguished. They are like the waves you see in the ocean: they move up and down and from one place to another. The spectrum of solar study can have different intensities. Distinguishultraviolet, visible and infrared radiation.
Light is moving energy
The spectrum of solar radiation figuratively resembles a piano keyboard. One end of it has low notes, while the other end has high notes. The same applies to the electromagnetic spectrum. One end has low frequencies and the other end has high frequencies. Low frequency waves are long for a given period of time. These are things like radar, television and radio waves. High-frequency radiations are high-energy waves with a short wavelength. This means that the wavelength itself is very short for a given time period. These are, for example, gamma rays, x-rays and ultraviolet rays.
You can think of it this way: low frequency waves are like going up a hill with a gradual climb, while high frequency waves are like going up a steep, almost vertical hill quickly. The height of each hill is the same. The frequency of an electromagnetic wave determines how much energy it carries. Electromagnetic waves that are longer and therefore lower frequencies carry much less energy than those with shorter wavelengths and higher frequencies.
This is why X-rays and ultraviolet radiation can be dangerous. They carry so much energy that if they get into your body, they can damage cells and cause problems like cancer and DNA changes. Things like radio and infrared waves, which carry much less energy, don't really have any effect onus no influence. That's good, because you certainly don't want to put yourself at risk by simply turning on stereo.
Visible light, which we and other animals can see with our eyes, is located almost in the middle of the spectrum. We don't see any other waves, but that doesn't mean they aren't there. In fact, insects can see ultraviolet light, but not our visible light. Flowers look very different to them than they do to us, and this helps them know which plants to visit and which ones to stay away from.
Source of all energy
We take sunlight for granted, but it doesn't have to be, because, in fact, all energy on Earth depends on this large, bright star at the center of our solar system. And while we're in it, we should also say thank you to our atmosphere, because it absorbs some of the radiation before it reaches us. It's an important balance: too much sunlight and the Earth gets hot, too little and it starts to freeze.
Passing through the atmosphere, the spectrum of solar radiation near the surface of the Earth gives energy in different forms. First, let's look at the various ways to transfer it:
- Conductivity (conduction) is when energy is transferred from direct contact. When you burn your hand with a hot frying pan because you forgot to put on an oven mitt, that's conduction. The cookware transfers heat to your hand through direct contact. Also, when your feet touch the cold tiles in the bathroom in the morning, they transfer heat to the floor through direct contact -conductivity in action.
- Dissipation is when energy is transferred through currents in a fluid. It can also be gas, but the process is the same anyway. When the liquid is heated, the molecules are excited, dispersed and less dense, so they tend to rise. As they cool, they fall down again, creating a cellular current path.
- Radiation (radiation) is when energy is transmitted in the form of electromagnetic waves. Think about how good it is to sit next to a fire and feel the welcome warmth radiate from it to you - that's radiation. Radio waves, light and heat waves can travel from one place to another without the aid of any materials.
Basic spectra of solar radiation
The sun has different radiation: from x-rays to radio waves. Solar energy is light and heat. Its composition:
- 6-7% UV light,
- about 42% of visible light,
- 51% NIR.
We receive solar energy at an intensity of 1 kilowatt per square meter at sea level for many hours a day. About half of the radiation is in the visible short-wavelength part of the electromagnetic spectrum. The other half is in the near infrared, and a little bit in the ultraviolet.
UV radiation
It is ultraviolet radiation in the solar spectrum that has an intensity greater than others: up to 300-400 nm. The portion of this radiation that is not absorbed by the atmosphereproduces sunburn or sunburn for people who have been in sunlight for long periods of time. UV radiation in sunlight has both positive and negative he alth effects. It is a major source of vitamin D.
Visible radiation
Visible radiation in the solar spectrum has an average intensity. Quantitative estimates of the flux and variations in its spectral distribution in the visible and near infrared ranges of the electromagnetic spectrum are of great interest in the study of solar-terrestrial impacts. The range from 380 to 780 nm is visible to the naked eye.
The reason is that most of the energy of solar radiation is concentrated in this range and it determines the thermal equilibrium of the Earth's atmosphere. Sunlight is a key factor in the process of photosynthesis, which is used by plants and other autotrophic organisms to convert light energy into chemical energy that can be used as fuel for the body.
Infrared radiation
The infrared spectrum, which spans from 700nm to 1,000,000nm (1mm), contains an important part of the electromagnetic radiation that reaches the Earth. Infrared radiation in the solar spectrum has three types of intensity. Scientists divide this range into 3 types based on wavelength:
- A: 700-1400 nm.
- B: 1400-3000 nm.
- C: 3000-1mm.
Conclusion
Manyanimals (including humans) have a sensitivity in the range of about 400-700 nm, and the usable color vision spectrum in humans, for example, is about 450-650 nm. In addition to the effects that occur at sunset and sunrise, the spectral composition changes primarily in relation to how sunlight directly hits the ground.
Every two weeks, the Sun supplies our planet with enough energy for the whole year. In this regard, solar radiation is increasingly being considered as an alternative energy source.
