The sun is a star and it produces energy in many forms, from perceptible heat, visible and invisible spectrums of light, radiation and more.
Life on earth would be impossible without the sun, but our atmosphere also protects us from the more dangerous aspects of solar radiation.
Humans tend to have a love-hate relationship with the sun. On the one hand, sunlight keeps us warm, creates food and shelter for us via plant life and gives us light.
On the other hand, as greenhouse gases trap more heat and the ozone layer allows more dangerous ultraviolet (UV) light through, the sun’s rays can be distinctly dangerous.
UV rays causes skin cancer in humans and animals, but can contrastingly improve other skin conditions like psoriasis. Humans need the sun biologically, as well, as it causes our bodies to produce vital Vitamin D.
The sun is approximately 149-million kilometres away, sending its energy to the earth in about eight minutes.
This energy is a combination of both light and UV rays. Known as a yellow dwarf star in the astronomy world, the sun is busy converting hydrogen to helium at its core by way of nuclear fusion.
The result of this action is energy. Solar radiation and sunlight make it possible for the earth to house life.
The negative aspects of our relationship with the sun are primarily the result of human irresponsibility: we develop skin cancer when we ignore our bodies’ signals to avoid sunlight, while we rather struggle with global warming because we have ignored the environmental concerns of our actions.
When we do not give solar radiation the respect it deserves, we are literally playing with fire.
Solar radiation
Solar radiation is thermal radiation emitted from the surface of the sun, which is powered by nuclear fusion. It is radiant energy emitted by the sun which comprises mostly of electromagnetic energy. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum. This is the part of light that can be seen by the human eye. The other half of solar radiation is mostly in the near-infrared part, with some in the ultraviolet (UV) part of the spectrum.
Health effects
Small amounts of UV are beneficial for people and essential in the production of vitamin D.
UV radiation is also used to treat several diseases, including rickets, psoriasis, eczema and jaundice. This takes place under medical supervision and the benefits of treatment versus the risks of UV radiation exposure are a matter of clinical judgement.
Prolonged human exposure to solar UV radiation may result in acute and chronic health effects on the skin, eye and immune system. Sunburn is the best-known acute effect of excessive UV radiation exposure.
Over the longer term, UV radiation induces degenerative changes in cells of the skin, fibrous tissue and blood vessels leading to premature skin aging, photodermatoses and actinic keratoses. Another long-term effect is an inflammatory reaction of the eye. In the most serious cases, skin cancer and cataracts can occur.
