The answer to the perennial question about the smallest thing in the universe has evolved with humanity. People once thought that grains of sand were the building blocks of what we see around us.
The smallest particles in the universe
Then the atom was discovered. The concept of atoms was first proposed by the Greeks, who believed that objects could be infinitely divided into two parts until there was one indivisible particle of matter. This unimaginably small unit could not be further divided and therefore was called “atom”, formed from the Greek word A-tomos. Where “A” means “no” and “tomos” – to divide.
It was considered indivisible until it shattered to reveal the protons, neutrons, and electrons inside. They, too, appeared to be fundamental particles before scientists discovered that protons and neutrons are made up of three quarks each.
So which particles are the smallest in the universe?
An electron is a negatively charged subatomic particle. It can be free (not bound to any atom) or bound to the nucleus of an atom. Electrons in atoms exist in spherical shells of different radii, representing energy levels. The larger the spherical shell, the higher the energy contained in the electron of the electrical conductors, the current flow arises from the movement of electrons from atom to atom separately and from negative to positive electrical poles in general. In semiconductor materials, current also occurs as the movement of electrons.
Positrons are the antiparticles of electrons. The main difference from electrons is their positive charge. Positrons are formed during the decay of nuclides, in the nucleus of which there is an excess of protons in comparison with the number of neurons, when decay occurs, these radionuclides emit a positron and neutrinos.
While the neutrino comes out without interacting with the surrounding matter, the positron interacts with the electron. During this annihilation process, the masses of the positron and the electron are converted into two photons, which diverge in nearly opposite directions.
A proton stable subatomic particle with a positive charge equal in magnitude to the unit of an electron charge and a rest mass of 1.67262 × 10 -27 kg.
About ten years ago, both spectroscopy and scattering experiments seemed to converge at a proton radius of 0.8768 femtometers (millionths of a millionth of a millimeter).
But in 2010, a new twist on spectroscopy challenged this idyllic consensus. The team measured a proton radius of 0.84184 femtometers.
You know that neutrons are in the nucleus of an atom. Under normal conditions, protons and neutrons stick together in the nucleus. During radioactive decay, they can be knocked out of there. Neutron numbers are capable of changing the mass of atoms because they weigh about the same as a proton and an electron together.
Neutrons can be found in almost all atoms, along with protons and electrons. Hydrogen -1 is the only exception. Atoms with the same number of protons, but with a different number of neutrons, are called isotopes of the same element.
The number of neutrons in an atom does not affect its chemical properties. However, this affects its half-life, a measure of its stability. An unstable isotope has a short half-life in which half of it breaks down into lighter elements.
Imagine a ray of yellow sunlight shining through a window. According to quantum physics, this beam is made up of billions of tiny packets of light called photons that flow through the air. But what is a photon?
A photon is the smallest discrete amount or quantum of electromagnetic radiation. This is the basic unit of the whole world.
Photons are always in motion and in a vacuum move at a constant speed to all observers 2.998 × 10 8 m / s. This is usually called the speed of light, denoted by the letter c.
According to Einstein’s quantum theory of light, photons have an energy equal to their vibration frequency multiplied by Planck’s constant. Einstein proved that light is a stream of photons, the energy of these photons is the height of their vibration frequency, and the intensity of light corresponds to the number of photons.
Quark is one of the fundamental particles in physics. They combine to form hadrons such as protons and neutrons, which are components of the nuclei of atoms.
A quark has a limitation, which means that quarks are not observed independently, but always in combination with other quarks. This makes it impossible to directly measure properties (mass, spin and parity); these traits must be deduced from the particles composed of them.
A millionth of a second after the Big Bang, the universe was an incredibly dense plasma, so hot that no nuclei or even nuclear particles could exist.
Plasma consisted of quarks, particles that make up nucleons and some other elementary particles, and gluons, massless particles that “transfer” force between quarks.
Gluons are exchange particles for color force between quarks, similar to the exchange of photons in electromagnetic force between two charged particles. The gluon can be considered the fundamental exchange particle that underlies the strong interaction between protons and neutrons in the nucleus.
Muons have the same negative charge as electrons, but 200 times their mass. They occur when high-energy particles called cosmic rays slam into atoms in the Earth’s atmosphere.
Traveling at a speed close to the speed of light, muons shower the Earth from all directions. Each arm-sized region of the planet is hit by about one muon per second, and particles can travel hundreds of meters of solid material before they are absorbed.
According to Cristina Carloganou, a physicist at the Clermont-Ferrand Physics Laboratory in France, their ubiquity and penetrating power make muons ideal for visualizing large, dense objects without damaging them.
A neutrino is a subatomic particle that is very similar to an electron, but lacks an electric charge and a very small mass, which may even be zero.
Neutrinos are one of the most abundant particles in the universe. However, because they interact very little with matter, they are incredibly difficult to detect.
Very large and very sensitive detectors are required to detect neutrinos. Typically, low-energy neutrinos travel many light years of normal matter before interacting with anything.
Hence, all ground-based neutrino experiments are based on measuring a tiny fraction of neutrinos that interact in reasonably sized detectors.
1. Higgs boson
Particle physics usually has a hard time competing with politics and celebrity gossip for headlines, but the Higgs boson has received serious attention. Perhaps the famous and controversial nickname for the famous boson, “Particle of God”, made the media buzz.
On the other hand, the intriguing possibility that the Higgs boson is responsible for all the mass in the universe is breathtaking.
The Higgs boson is, if not the most expensive particle of all time. This is a slightly unfair comparison; for example, the discovery of an electron took a little more than a vacuum tube and a real genius, and the search for the Higgs boson required the creation of experimental energies that were previously rare on planet Earth.