The forces of nature`s law
The idea of a fundamental simplicity underlying the observed diversity of the universe is a powerful one that has stood the test of time. Admittedly, the nature of truly elementary particles has undergone a continual change, from English chemist John Dalton's atoms to the particles of the Standard Model of particle physics. Nevertheless, the basic tenet of a few underlying particles and their interactions being responsible for nature's enormous diversity still motivates physicists.
The observed phenomena in nature are all basically manifestations of 4 fundamental forces: gravity, electromagnetism, the weak nuclear force and the strong nuclear force.
Gravity is the weakest of them all; yet it is all-pervasive because all particles feel it. But at sub-microscopic distances, gravity is too weak to be significant.
Electromagnetism is the force between electrically charged particles. Depending on the charge, the force can be either attractive or repulsive. Quantum electrodynamics (qed), which incidentally is the most successful theory known to US since its agreement with experiments is unmatched, looks at electromagnetic interaction between charged particles as originating in the exchange of particles called photons.
The weak nuclear force is responsible for certain kinds of radioactive decay, classified together as beta decay. The electroweak theory, developed in the '60s by Steven Weinberg, Sheldon Glashow and Abdus Salam, treats the weak force and the electromagnetic force as different forms of the more fundamental electroweak force, in the same manner as electricity and magnetism are considered the 2 aspects of electromagnetism. The electroweak theory requires the existence of 4 particles, one of which is the photon of electromagnetism. The other 3 are the positively and negatively charged W particles and the neutral Z particle. Striking confirmation for this theory came from the discovery of the W and Z particles by CERN researchers in 1983.
The strong nuclear force is what holds the nucleus together. In the '70s, quantum chromodynamics (qcd) was developed to explain the strong nuclear force. In qcd, nuclear particles like the proton are not considered elementary but conceived as clusters of truly fundamental quarks. These quarks are bound together by the exchange of particles called gluons. Quarks possess a quality, arbitrarily called "colour", which is comparable to electric charge. There are 3 types of "colours". Quarks of the same "colour" repel each other and those of different "colours" attract each other.
The electroweak theory, along with the qcd, is what is usually referred to as the Standard Model. Although this model has been validated in several experiments, there are still many unanswered questions.
One of the primary constituents of the electroweak theory is the Higgs particle. This particle is responsible for breaking the electroweak force into the electromagnetic and weak forces. It is also the particle that gives mass to particles like quarks and electrons. Unfortunately, the search for the Higgs particle has so far proved futile.
Other puzzles of the Standard Model include the seemingly arbitrary masses of the fundamental particles, the arrangement of these particles into families that are replicated and the mass of the Higgs particle itself. It is these conundrums of the Model that physicists sought to understand with bigger accelerators and more refined theories like the Grand Unified Theories and Supersymmetry.
Related Content
- Women paying the cost of the climate crisis with their wombs: quantifying loss and damage faced by women battling drought, debt and migration
- Challenges and policy implications of a low carbon pathway for Odisha
- Ecological threat report 2023
- Activating the green recovery action plans in Africa through nature-based solutions and natural capital approaches
- Socio-economic footprint of the energy transition: Southeast Asia
- Global trends: forced displacement in 2022