I assume Radiation burns would do the same type of damage, but how does that damage increase the chances for skin cancer if other sources do not?
In: 6
Ultraviolet and more energetic radiation can knock electrons out of molecules. You can think of electrons as tiny magnets that enable structures of atoms to be constructed. When they’re knocked out, the structures change or break apart. Cells have mechanisms for committing suicide if they’ve sustained too much such damage, but in rare cases that mechanism, along with the one that regulates growth, breaks at the same time, and you get cancer.
Less energetic radiation cannot directly affect the electrons, but it can still generate so much heat, which is vibration in the molecules, that they change shape or shake apart entirely. This more generalized damage has less of a chance to cause the specific damage that leads to cancer, and more of a chance to kill the cell outright. There’s still some risk though. Someone recently posted in a other ELI5 how throat cancer is more prevalent in cultures that drink very hot beverages, including hot water.
while called a burn, sunburns and radiation burns are a bit different. rather than combustion or simply destruction of a cell due to intense heat that cooks it, sunburns are when high energy particles such as UV light penetrate the skin cells. Eventually those particles hit something they cannot penetrate, and when they do, they offload the energy they were carrying, usually into the innards of the cell, such as your DNA, damaging it. Once damaged enough the cell triggers its self-destruct safeguard and dies. Sunburns are the result of a large amount of healthy cells dying from being too badly damaged.
The damage to DNA is also why there is an increased cancer risk. The body has several safeguards in place to prevent the rise of malfunctioning cells. Cells go through rigorous checks before they divide to make sure they DNA was copied properly, they self destruct if they get too badly damaged, and your immune system usually cleans out the defective cells when the first two safeguards fail. Cancer is when all three of those safeguards fail and the cell is replicating out of control because of its damaged DNA no longer telling it to wait. The more often the DNA of your cells are damaged, such as when sunburn, the higher likelihood of a case where all three safeguards fail and the cell begins to multiply unchecked. Burns from heat usually damage the entire cell, so even if the DNA might have been damaged the cell doesn’t survive anyways.
Chemical Burns are different from both radiation and heat burns. While it feels like a burn in many cases, chemical burns are a result of corrosive or reactive chemicals reacting with and destroying your skin cells through chemical reactions rather than heat or radiation. Depending on the chemical involved an increased risk of cancer can be present or not.
Physics answer: Sunburns are caused by ultraviolet light, a wavelength of light just outside of human vision. All light is a form of electromagnetic radiation.
Infrared has a long wavelength, and it’s just below visual spectrum range. This is considered ‘heat’ wavelength and can cook the upper most layer of skin. The skin absorbs this wavelength and there isn’t really enough specific energy to damage the DNA. Think of the ‘red’ lights at a restaurant used to keep the food warm.
Ultraviolet is above the visual spectrum of light, and has enough energy to pass into the upper layers of skin cells. The wavelength is small enough to get into the cells and start messing with things, sometimes killing or mutating it. (I assume this is why sunburns peel.) Welding can cause UV from the intense white hot welding arc. Welders wear hoods and sleeves to protect from this artificial sunburn.
High energy, short wavelength (eg: x-ray, gamma) radiation can penetrate through to the deeper cells, like organs, and affect DNA, leading to severe mutations and possibly death. (Other posts cover this fairly well.) This can be from a radioactive element – cesium being a common industrial source, or an X-ray tube designed to emit specific high energy waves that will penetrate all but dense metals.
Latest Answers