Energy is the defining property of our physical world, and therefore the most important tool for understanding nature, hence the most commo...

 According to the current view of science, elementary particles, like electrons or quarks, are elementary because they cannot be broken down...

 Mass is the defining property of our material world. Everything made of matter has mass. Yet mass is not necessarily an unambiguous propert...

 According to the Standard Model of particle physics, the most fundamental building blocks of our material world are electrons and quarks, e...

 A general definition of symmetry: If a certain change does not change a property, then that property is symmetric with respect to that part...