We're all radioactive, so let's quit worrying about it

Many people are afraid of radiation, viewing it as an invisible, man-made, and lethal force, and this fear frequently fuels resistance to nuclear power. In truth, most radiation is natural, and without it, life on Earth would be impossible. We have simply harnessed radiation for our own purpose in nuclear power and nuclear medicine, just as we have harnessed fire or the medicinal capabilities of plants, both of which have the potential to hurt. Unlike certain natural poisons, humans have evolved to deal with modest amounts of radiation, and only very large quantities are detrimental. A fair comparison for this paracetamol is that one pill will heal your headache, but taking the entire box at once can kill you.

Nearly 14 billion years ago, the Big Bang produced radiation in the form of atoms known as primordial radionuclides (primordial meaning from the beginning of time). These have now become a part of everything in the cosmos. Some have extraordinarily long physical half-lives, which is a measure of how long it takes for half of their radioactivity to fade away. One radioactive form of thorium has a half-life of 14 billion years, one of uranium has a half-life of 4.5 billion, and one of potassium has a half-life of 1.3 billion. 

Radionuclides from the past are still present in rocks, minerals, and soils today. Their decomposition generates heat in the Earth's center, transforming its molten iron core into a convecting dynamo that maintains a magnetic field strong enough to protect humans from cosmic radiation, which would otherwise wipe out life on Earth. Without radiation, the Earth would have progressively cooled into a lifeless, stone globe with a cold, iron ball at its center, and life would not have existed. Space radiation interacts with elements in the Earth's upper atmosphere and some surface minerals to create new "cosmogenic" radionuclides, which include forms of hydrogen, carbon, aluminum, and other well-known elements. Except for one radioactive type of carbon with a 5,700-year half-life, which allows archaeologists to utilize it for radiocarbon dating, the majority disintegrate fast.

The majority of the radiation we are exposed to comes from primordial and cosmogenic radionuclides. Plants absorb radiation from the earth, and it may be found in foods such as bananas, beans, carrots, potatoes, peanuts, and brazil nuts. Beer, for example, includes a radioactive version of potassium, but only about a tenth of what carrot juice contains. Radionuclides from meals are mostly eliminated by human systems, although some stay for extended periods of time (their biological half-life is the time for our bodies to remove them). As that radioactive form of potassium decays, it generates high-intensity gamma rays that exit the human body, guaranteeing that we are all slightly radioactive.

We have historically been unaware of the existence of radioactivity in our surroundings, but our bodies have naturally adapted to cope with it. In reaction to radiation damage, our cells have evolved defensive mechanisms that accelerate DNA repair. Henri Becquerel, a French physicist, discovered natural radioactivity in 1896. Marie and Pierre Curie created the first artificial radioactive materials in the 1930s, which have since been employed in research, business, agriculture, and medicine.

Radiation therapy, for example, is still one of the most significant cancer treatment modalities. Researchers are actively attempting to alter cancer cells to make them less able to mend themselves in order to boost the efficacy of therapeutic radiation. In "nuclear medicine," we employ radioactive material for both diagnosis and therapy. Depending on where in the body the therapy or diagnosis is required, patients are injected with certain radionuclides. Radioiodine, for example, accumulates mostly in the thyroid gland, whereas radium primarily accumulates in the bones. The radiation released is used to diagnose malignant tumors. Radionuclides are also used to treat cancer by directing the radiation they release at the tumor. 99mTc (technetium) is the most often used medical radioisotope, with 30 million operations performed globally each year. It, like many other medical isotopes, is man-made, generated from a parent radionuclide produced by the fission of uranium in a nuclear reactor.

Despite the benefits that nuclear reactors provide, people are concerned about the radiation they emit, either as a result of radioactive waste or accidents like Chernobyl or Fukushima. However, in compared to other major energy sources, nuclear power generation and accidents have killed far fewer people. We are concerned that radiation phobia is undermining climate mitigation efforts. Germany, for example, presently generates around a quarter of its electricity from coal, but deems nuclear to be risky and is closing down its remaining nuclear power plants.

Modern reactors, on the other hand, produce very little waste. This material, together with waste from decommissioned reactors, may be immobilized in cement and glass and disposed away deep below. In addition, unlike coal, gas, or oil, radioactive waste emits no carbon dioxide. We now understand how to harvest radiation safely and use it to our and the planet's advantage. We risk depending on fossil fuels for longer if we are too afraid of it and reject nuclear power as a key energy source. This, not radiation, is the biggest threat to ourselves and the world.

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