Physics

Physics is the Art of finding things out. Hear Feynman talk about it:

Physics is the core of all Science, as emphatically expressed by Rutherford, deemed the greatest experimentalist since Faraday by the Encyclopædia Britannica, who famously expressed that “all science is either physics or stamp collecting”.

There is no scientific discipline, in fact hardly any discipline at all, where the concepts of motion, space, time, matter, energy, causality, information, error, etc., are not invoked, and these are what Physics is about. When applied to particular cases, Physics becomes Chemistry (the science of how matter is structured), Optics (the science of how light propagates), Astronomy (the science of celestial objects), Climatology (the science of atmosphere and oceans), Engineering (the science of implementing technology), etc. Even seemingly more remote fields such as Biology, Medicine or Geology, or more fundamental ones such as Mathematics or Computing Sciences, are deeply rooted into Physics and increasingly so as scientific expertise progresses. The field of Quantum Biology and Quantum Computation, for instance, are quickly evolving and will shape the tomorrow’s landscape of these disciplines. In a sufficiently advanced technology, everything comes back to the rule of physical laws. In this way, a computer bit becomes a qubit encoded on a bunch of few particles ruled by the principle of atomic physics, rather than by those of abstract platonic mathematics.

Physics is therefore the keystone of Science.

Some of the topics tackled by Physics:

• Astronomy & cosmology
• Atomic & Molecular physics
• Mechanics
• Optics
• Electromagnetism
• Chemistry
• Quantum mechanics
• Quantum optics
• Relativity (Special and General)
• Particle physics
• Solid-state physics
• Condensed matter physics
• Quantum field theory
• Theory of Everything

Not part of physics per se, but related:

• Fields in Mathematics
• Philosophy
• Epistemology
• History of science

See also the other scales.

Fundamental concepts of Physics, historically, include conservation laws (e.g., conservation of energy or momentum). Later, with Noether's theorem, it got clarified that symmetries are a more fundamental underlying concept. In its wake follows the idea of gauge theory impulsed by Hermann Weyl and the rise of group theory. Maybe the latest step forward is the understanding of the role played by topology.