Particle physics in your body

    There is a hypothesis that someone already drank every molecule of water on Earth at least once in the entire multimillion history of the evolution of life. But if you look even deeper - at the level of chemical elements - it turns out that our body is much older, no matter how old you are. Ivan Lozovoy talks about this and many other things in a new video of our friends on the Sci-One channel. And read the text version under the cut.



    14 billion years ago, our universe was a hot, superdense bit, which expanded incredibly fast. All the matter and antimatter that were in those times should have been destroyed and left us nothing but energy. But for some reason, part of the matter has been preserved, and now we live in the world of elementary particles. And few people guess what kind of world it really is, and what place we occupy in it.

    Approximately 99% of your body consists of atoms of hydrogen, carbon, nitrogen and oxygen. There are, of course, other elements, without which one cannot survive, but they are much smaller. Most of the cells in your body are renewed every 7–15 years, but many of the particles you are made of are already millions of millennia. Your hydrogen atoms are the same age as the Big Bang. Atoms of carbon, nitrogen and oxygen appeared with the first stars in the universe. The heaviest elements in your body appeared during supernova explosions.

    The size of an atom depends on how its electrons are located. The nucleus inside the atom is approximately 100 thousand times smaller than the element itself. If the core were the size of a pea, the atom would be the size of a football stadium. And if free space is removed from an atom, a person could fit in a speck of dust, and all of humanity in a single sugar cube.
    These particles make up only the smallest part of your body weight. Each proton and neutron inside the nucleus of an atom consists of three quarks. The mass of quarks, which appear due to their interaction with the Higgs field, is only a few percent of the mass of a proton or neutron. The carriers of a strong nuclear interaction that holds quarks together — gluons — are completely weightless. But if the mass of your body is not the mass of these particles, then where does it come from?

    It's all about energy. Almost the entire mass of the human body consists of the kinetic energy of quarks and the binding energy of gluons.

    Particles that we produce


    Your body is a small deposit of radioactive elements. Every year you get a dose of natural radiation of 400 microzivertus - it is generated inside you. The same amount of radiation you receive during four chest X-rays. Also, the level of radiation of your body can increase by 10-20 microsieverts every eight hours while you sleep next to your loved one, just as radioactive.

    You emit radiation because the food and drinks you consume and even the air you breathe contain radionuclides such as potassium-40 and carbon-14. They interact with the molecules of your body, decay and produce radiation. When potassium 40 decays, it emits a positron - the antiparticle of the electron. Thus, your body contains a small amount of antimatter. On average, each person emits more than four thousand positrons per day, about 180 positrons per hour. But soon these positrons collide with your electrons and turn into radiation in the form of gamma radiation.



    Particles we encounter


    The radioactivity of your body is only a part of the radiation that you encounter every day, without receiving harm. The food you consume, the house you live in, the stones and the soil you walk on give you a low level of radiation. If you just eat a walnut or go to the dentist, you will receive a radiation level of several tens of microsievert. By the way, smoking can increase the level of radiation by 160 thousand microsieverts. And then there is cosmic radiation. It has an extraterrestrial origin and constantly penetrates the atmosphere. Here, this radiation collides with other nuclei and produces mesons, many of which decay into particles, such as muons and neutrinos. These particles, in turn, fall on the surface of the Earth and penetrate into your body at a frequency of about 10 atoms per second. They add about 270 microsieverts to your annual radiation dose. These cosmic particles can sometimes disrupt your genetics and produce small mutations, thereby contributing to evolution.



    The sun constantly bombards us with photons that allow us to see this world. But the Sun is attacking us with particles called neutrinos. Neutrinos are regular guests of your body, penetrating you in the amount of 100 trillion per second. The sun is not the only source of these particles, they also come from nuclear reactions inside other stars, and even from nuclear reactions on our own planet.



    Many neutrinos were formed in the first few seconds after the Big Bang, and they are even older than your own atoms. Neutrinos very weakly interact with other particles, and therefore their visits for your body pass almost without a trace.

    Also, your body most likely constantly interacts with dark matter particles. It does not emit, reflect, or absorb light, and therefore is very difficult to detect. However, scientists believe that dark matter makes up approximately 80% of all matter in the universe. Given such a large number, it is estimated that hundreds of thousands of these particles interact with your body every second.

    But dark matter weakly interacts with the matter of which you consist, and therefore the effects of this interaction are likely to be invisible. The next time you get interested in how particle physics affects your life, just look at yourself.

    Source

    Read more on the topic:


    Also popular now: