The effects of cosmic rays on living things
Life on Earth was made possible thanks to the atmosphere and the Earth’s magnetic field, in fact, without these two elements, the earth’s soil would be bombarded with an enormous quantity of particles and rays making any form of life impossible; this is probably why there is no life elsewhere in the Universe because the other telluric planets do not have this atmosphere, making all life as we know it possible. There are some effects of cosmic rays on living things and the human body.
On the other hand, astronauts going to space (such as on the international space station or the planned trip to Mars) are exposed to a higher dose of radiation. This is why spacecraft undergo tests to verify their impermeability to particles and thus protect astronauts. The planes and their occupants are also exposed to it, this exposure depends on the altitude of the plane but also on the route taken by the plane. In fact, the radiation doses received are greater the higher the altitude and they are also greater at high latitudes (near the poles).
Outside the Earth’s magnetic field, the maximum cosmic ray fluence rate is approximately:
– 4 protons cm²/second
– 0.4 alpha particle cm²/second
– 0.04 high energy particle cm²/second
Every cell in the body should therefore be hit by:
– one proton every three days
– an alpha particle every month
– one high energy particle every year
But the human body contains about ~3.7 × 1013 (or around 30 trillion) cells. This means that every second:
– about 40 million cells are crossed by a proton
– about 4 million cells are crossed by an alpha particle
– about 300,000 cells are crossed by a high energy particle
The particles making up the radiation present a danger because they can damage the cells, this damage can have consequences on the life of the cell and on its ability to divide, it can therefore affect tissues and organs.
There are two types of cosmic radiation threats to living things:
– exposure to high doses of radiation is a danger to health and even life;
– exposure to lower doses of radiation may represent a longer-term risk.
There are also several types of effects of cosmic rays on the living:
– acute effects:
these are due to high doses received over a short period of time, they lead to the destruction of exposed cells and organs, they therefore generate observable health effects in the more or less short term. These may include, for example, skin burns, vomiting, destruction of the bone marrow or the intestinal mucosa, which can lead to the death of the exposed person.
These effects are only observed during exposure to a very high dose of ionizing radiation, following accidental exposure (during accidents in an installation, or untimely handling of a source of radioactivity), or during voluntary exposure (of patients to radiation, for therapeutic purposes);
Space radiation can lead to other effects. Radiation can alter the cardiovascular system, damaging the heart, harden and narrow arteries, and/or eliminate some of the cells in linings of the blood vessels, leading to cardiovascular disease.
– “stochastic” effects, ie delayed in time:
are due to a transformation of the cells which, several years after irradiation, can lead to diseases such as leukemia or various cancers in the exposed population. But there are no biological means to differentiate, for example, lung cancer due to tobacco and cancer due to exposure to ionizing radiation, which is why the epidemiological studies carried out are on populations (in numbers sufficient) having been significantly exposed to ionizing radiation;
– with regard to exposure to low doses (of the order of a microsievert or even a millisievert), the effects, if they exist, are so weak that it would be very difficult, if not impossible, to detect them thanks to epidemiological studies.
At present, it is not possible to conclude as to the existence, or not, of a radiation threshold below which there would no longer be any effects linked to exposure to ionizing radiation. There is nevertheless an international consensus which considers that any exposure (even weak) to ionizing radiation is likely to induce an effect on the scale of a population. At low doses, for which a real risk could not be proven, the probability of developing stochastic effects is considered to be proportional to the dose received. Quantification of the dose-effect relationship is established by extrapolation from what is observed at higher doses.
On Earth, what types of radiation are humans exposed to?
Life on Earth was made possible thanks to the atmosphere and the Earth’s magnetic field, in fact, without these two elements, the earth’s soil would be bombarded with an enormous amount of particles and rays making any form of life impossible.
There are two types:
- natural ionizing radiation from cosmic sources (eg, galactic, solar radiation) and terrestrial sources (eg, radioactive material found in rocks, radon);
- radiation from artificial sources (eg, diagnostic x-ray imaging, nuclear reactors).
Cosmic radiation is ionizing radiation from outer space. The stars and the sun, through solar flares, release radioactive rays.
On the surface of the ground, we are doubly protected against these cosmic rays. On the one hand, most of these are retained and absorbed during their passage through the Earth’s atmosphere, and, on the other hand, the Earth’s magnetic field deflects the cosmic particles.
Information: Cleverly Smart is not a substitute for a doctor. Always consult a doctor to treat your health condition.
Sources: PinterPandai, HealthLine, NASA, International Atomic Energy Agency (IAEA), Scientific Reports via Springer Nature, Joseph A Frank via ResearchGate, The Regents of The University of California
