The Power of the Sun

As the summer season approaches, it is critical to understand the expected high temperatures and amount of light, as well as the necessary precautions for protection from the Sun.

Reading Time: 5 minutes

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By Grace Louie

As the Northern Hemisphere finally gets closer to entering the summer season, more people will begin to focus a lot more on one thing: the Sun. 

The Sun is around 93 million miles away from the Earth, but its energy has a significant impact on the planets which orbit it. Through the process known as nuclear fusion, where hydrogen atoms combine to form helium, vast amounts of energy are released as light and heat. This energy travels across space and reaches Earth, where it warms the global atmosphere, oceans, and land. Mercury, being the planet closest to the Sun, receives the highest amount of solar energy but does not retain too much heat due to its thin atmosphere. Meanwhile, planets like Jupiter, Saturn, Uranus, and Neptune receive much less solar energy due to their greater distance from the Sun. Solar heat transfers through three different processes: conduction, convection, and radiation.

Conduction is the process by which heat is directly transferred between surfaces through direct contact. Though heat transfer directly from the Sun and the Earth is not possible due to their spatial differences, when the Sun’s radiation strikes the surface of the Earth, the surface temperature rises due to conduction, releasing heat into the atmosphere. Convection is movement caused within a fluid due to the differences in temperature and density between two materials so that the colder, denser material sinks below the hotter and less dense material. This can be seen in the convection cells of the Earth, which are affected by the Sun’s uneven heating of the Earth, causing density differences. Finally, radiation is the release of energy through the movement of subatomic particles and electromagnetic waves. Solar radiation is a prime example of how the heat and light from the Sun is absorbed by the Earth as infrared and visible light, respectively. 

Though the summer season may signal a break from school and perfect beach temperatures, it is critical to understand the intensified risk of harm that comes with the season. For instance, during the summer, the amount of insolation, or incoming solar radiation, is at its maximum. In other words, the amount of ultraviolet (UV) radiation absorbed increases. UV radiation is a form of radiation released by the Sun that is separated into three categories depending on its wavelength frequency: UVA, UVB, and UVC. UVA rays have the longest wavelength and are able to penetrate through the atmosphere. UVB rays affect the top skin layer, causing the tanning of skin, and may cause cancer, redness, and burns. Finally, UVC rays, which have the shortest wavelength, do not reach the Earth’s surface. Typically, the shorter the wavelength, the higher the amount of energy, and thus harm, but due to the presence of ozone, also known as the Earth’s UV radiation-absorbing gas, Earth has a strong ability to absorb these shorter wavelengths.

Exposure to UV radiation is of concern if not monitored properly because it forms various free radicals, or electrons, which stress cells by hindering DNA replication, leading to cell damage. Through ionization, a process in which electrons break away from their respective atoms and affect other chemical bonds, UV radiation can also disrupt the DNA double helix structure by breaking the delicate hydrogen bonds that connect the base pairs together. This may cause mutations in the genes or skin cells which may lead to squamous cell carcinoma, a type of skin cancer. 

Typically, darker skin color has a slightly greater protection from the Sun because it contains a greater amount of melanin, the substance that produces bodily coloring, meaning that more UV light is absorbed in the upper skin layer rather than penetrating skin cells. However, doctors believe that the difference between high and low amounts of melanin is insignificant in preventing cell carcinoma. Regardless of skin color, scientists believe that people who spend over 30 minutes in the sunlight without protection have a high risk of getting skin cancer. Though there is no direct exponential relationship between exposure to the Sun and risks of getting skin cancer, if there is an overall high amount of exposure to UV radiation accumulated in a lifetime, the risk of cancer increases, especially if exposure happens during peak UV radiation times.

Skin cancer can be treated by cryotherapy, the use of liquid nitrogen to freeze and kill the skin cancer cells, or Mohs surgery, a process in which only the diseased tissue is removed, among other treatments. However, doctors recommend that people prioritize taking preventive measures to reduce the risk of getting harmed by the Sun. For instance, one can check the UV Index to set limits on the amount of time spent outside. More specifically, if the forecast says that the UV Index will be five or above, one should use Sun protection. The UV Index is a number on a scale from 1-11+ that predicts how intense the UV rays will be at a particular time and place. This varies depending on cloud coverage, time of day, seasons, and ozone, so a five on the UV index scale indicates that there will be moderate exposure to UV radiation. Additionally, applying sunscreen can protect oneself from the Sun. 

Sunscreen, though not recommended for babies less than six months old due to the development of skin, is effective at filtering out UV rays. This is due to their physical blockers, such as titanium dioxide or zinc oxides, that sit on the skin surface and reflect UV rays. Since both zinc oxide and titanium dioxide are photostable, meaning that they do not degrade when exposed to sunlight, they ensure consistent protection. Additionally, they have mirror-like qualities because of their high refractive index, or ability to bend light to a significant degree. Hence, they can chemically absorb the UV rays before the UV penetrates the skin cells.

Though the Sun’s energy does pose harmful effects, scientists also believe that without the Sun’s radiation, life would have never existed due to the lack of photosynthesis and freezing temperatures that may drop as low as -273°C. Additionally, without solar radiation, organisms would have a lack of Vitamin D, a critical nutrient that helps the body absorb calcium for strong bones. Moreover, it is critical to understand that even when not in the summer season, UV radiation can be dangerous, so protection is highly recommended all year long. 

By understanding and respecting the Sun’s power, students and families can enjoy the summer season to its fullest while also safeguarding personal health. So, whether you are excited or troubled by this upcoming summer season, it is critical to remember to protect yourself and appreciate the balance that makes the season so challenging and unique.