All the forces we face every day can be summarized in four categories – gravity, electromagnetism, strong and weak. Recently, physicists have found possible signs of the fifth fundamental force of nature, which we wrote about earlier. It’s time to figure out how the main ones work.
The foundation of the universe according to the laws of physics
What powers do you know? The force of gravity, tension of the thread, compression of a spring, collision of bodies, force of friction, explosion, resistance of air and medium, surface tension of a liquid, van der Waals force – and the list does not end there. However, all these forces are derivatives of four fundamental ones. They are also called fundamental interactions, and they are responsible for all processes in the universe. If elementary particles can be compared to pieces of a mosaic, then the interactions between them are glue. In order from weakest to strongest, scientists have identified four interactions – gravitational, weak, electromagnetic and strong. They cannot be reduced to simpler ones, which is why they are called fundamental.
It is worth considering that today the existence of four fundamental interactions is reliably known (not counting the Higgs field).
Gravity – gravitational interaction
Gravity is the attraction between two objects that have mass or energy. Everyone has observed this fundamental effect and thanks to it a person can sit, stand or lie down. Gravitational force is manifested in the fall of a stone from a cliff; the movement of the planet around the star; sea tides, for which the moon is responsible. Gravity is the most intuitive and familiar of the fundamental forces, and it is not easy to explain.
Isaac Newton was the first to propose the idea of gravity, supposedly inspired by an apple falling from a tree. He described it as a literal attraction between two objects. Centuries later, Albert Einstein, in his general theory of relativity (GR), suggested that gravity is not attraction or force. On the contrary, it is a consequence of the fact that objects bend space-time. A large object works with space-time in much the same way as a large ball placed in the middle of a sheet acts on this material, deforming it and causing other, smaller objects on the sheet to fall towards the middle.
Weak strength and particle decay
Weak force, or weak nuclear force, is responsible for the decay of particles. It is the literal transformation of one type of subatomic particle into another. So, for example, a neutrino deviating from a neutron can turn a neutron into a proton, and a neutrino into an electron.
Physicists describe this interaction through the exchange of bosons. These force-bearing particles, namely some of their species, are responsible for weak interaction, electromagnetic interaction and strong interaction. In weak interactions, bosons are charged particles called W and Z bosons. When subatomic particles – protons, neutrons, and electrons – are 10-18 meters (0.1% of the proton’s diameter) apart, they can exchange these bosons. As a result, subatomic particles disintegrate into new particles.
Electromagnetic force
Electromagnetic force (Lorentz force) acts between charged particles – negatively charged electrons and positively charged protons. Opposite charges attract each other, while identical charges repel. The more charge, the more power. And like gravity, this force can be felt.
As the name suggests, electromagnetic force has two parts: electrical force and magnetic force. At first, physicists described these forces separately from each other, but later realized that they are components of one.
The electrical component acts between charged particles, whether they are moving or not, creating a field. With it, charges can influence each other. But as soon as they start moving, these charged particles also show the second component – magnetic force. When they move, they create a magnetic field around them. Therefore, when electrons penetrate the wire to, for example, charge a computer or phone or turn on a TV, the wire becomes magnetic.
Strong Force – Trillions Trillions Trillions Stronger Than Gravity
Strong nuclear force, or strong nuclear force, is the most powerful of the four fundamental forces of nature. According to HyperPhysics, this is 6 thousand trillion trillion trillion (that’s 39 zeros after 6) times stronger than gravity. This is because it ties fundamental particles of matter together to form larger particles. It holds together the quarks that make up protons and neutrons, and part of the strong force also holds together the protons and neutrons of the atomic nucleus.
