The unseen world of atoms and particle physics governs the universe. There are some amazingly complex and intricate ways in which forces and particles interact. The apparent solidity and bulk of matter is really just force fields, which are really just forms of energy. The Higgs field that pervades the universe is the source of all mass. All of the matter and antimatter in the early universe should have annihilated itself, but an unknown process tilted the balance in favor of matter. After the first nanosecond, scientists have tracked the pathway of matter formation through the quark-gluon plasma, hadron era, Big Band nucleosynthesis and stellar nucleosynthesis.
People have always wondered about the nature of matter. Did matter always exist or did it have a beginning? Is matter continuous or composed of individual atoms? Do spirits and essences cause inanimate matter and life to grow and move, or is the world the result of mechanistic forces and the random movement of atoms. By the end of the 19th century, scientists determined that matter is composed of atoms and that mechanistic forces cause atoms to move. They thought that there was nothing more to discover; however, they should have realized that there were underlying particles in atoms that caused some elements to have common characteristics.
The discovery of radiation and beams of electrons in the late 19th century revealed that the atom was divisible. Scientists then discovered the arrangement of protons, neutrons, and electrons within atoms and developed the theory of quantum mechanics to explain the physics of atoms. The word quantum meant that electrons only occupy discrete orbitals and energy levels, which explained why electrons do not fall into the oppositely charged nucleus. Paul Dirac developed one of the most elegant equations in physics, which described the behavior of electrons, by merging quantum mechanics with Einstein's special theory of relativity.
Experiments in the 1930s revealed that the atom was divisible, would release energy, and undergo a chain reaction. The United States conducted a massive nuclear bomb development program during World War II, which culminated with the bombing of Hiroshima and Nagasaki. Since then, the United States and several other countries have developed massive nuclear arsenals. The future of civilization probably depends on treaties that lead to nuclear disarmament. An interesting question to consider is the philosophical implication of a universe that enables "intelligent" civilizations to annihilate life on their planet.
Scientists theoretically developed the Standard Model of particle physics and then confirmed it with supercollider experiments. Known mass particles include quarks, leptons, and neutrinos. Known force particles include gluons, photons, W bosons, and Z bosons. Unknown force and mass particles include the graviton and whatever is the basis of dark energy and dark matter. The Standard Model of Particle Physics describes the interactions between the force and mass particles. In 1964, Peter Higgs predicted that the Higgs boson gives mass to particles, and scientists confirmed its existence in 2012.
Scientist are not sure how matter formed in the Big Bang. According to theory, all of the matter and antimatter in the first moments of the universe should have annihilated each other. Once matter formed and the universe cooled, the path to quarks, nucleons, and then atoms is known. Scientists are working on hypotheses such as leptogenesis in order to explain how matter formed in the first place.
Other than a few light elements that formed in the Big Bang, all of the elements in the universe formed in stars in a process called stellar nucleosynthesis. Explaining how elements formed has played an important role in the validation of the Big Bang. It has also generated some interesting stories, such as the time Hoyle told Fowler to look for a certain resonance frequency in carbon. Stellar nucleosynthesis also produces the energy emitted by stars.