The concept that matter can never be created or destroyed is one of the fundamental principles of physics and is known as the law of conservation of mass. This law, along with the law of conservation of energy, is a cornerstone of the broader law of conservation of mass-energy, which states that the total mass and energy in a closed system remain constant over time.
The question of how matter was "made" or came into existence is a profound one and falls into the realm of cosmology, the branch of science that deals with the origin, structure, evolution, and eventual fate of the universe. According to current scientific understanding, the universe originated from a singularity in an event known as the Big Bang approximately 13.8 billion years ago.
During the Big Bang, all matter and energy in the observable universe were concentrated in an incredibly hot and dense state. As the universe rapidly expanded and cooled, matter began to form. In the early stages of the universe, only the simplest elements like hydrogen and helium were present. Over time, through processes like nuclear fusion in stars and supernova explosions, heavier elements were formed. These processes allowed for the creation of elements like carbon, oxygen, nitrogen, and all the other elements that make up the periodic table.
In summary, the matter we observe in the universe today, including the elements that make up our bodies and the world around us, originated from the high-energy conditions of the early universe during the Big Bang. The formation and evolution of matter have been governed by the fundamental laws of physics, including the conservation of mass and energy, throughout the history of the universe.