Mass

Full Title or Meme

Mass is the concept that enables us to say that an object (or an idea) is weighty or massive.

Context

• Issac Newton needed a mathematical definition of what caused gravity and so defined it thus

  The quantity of matter is the measure of the same, arising from its density and bulk conjucntly ... It It is this that I mean hereafter everywhere under the name body, or mass. And the same is known by the weight of each body, for it is proportional to the weight, as i have found by experiments on pendulums, very accurately made, which shall be shown hereafter.

• There are these types of mass as commonly defined:

1. rest. This isn't much help with objects, like photons, that are never known to be at rest but meet the other criteria.
2. inertial. F = ma, resistance to acceleration
3. gravitational. F = m₁m₂r²
4. Momentum. mass relates a body's momentum p to its linear velocity v: p = mv.
5. Energy E = mv² / 2

Solutions

Einstein

General Relativity describes on how mass and energy influence the curvature of spacetime, which in turn affects the motion of objects. Symmetry braking gave us protons and neutrons, which make up the bulk of atomic mass. The energy from these interactions, according to Einstein’s equation (E=mc^2), contributes significantly to the mass of these particles. Symmetry braking allowed the particles to obtain a mass, without breaking other parts of particle physics theory that were already believed reasonably correct. There are about a dozen alternates to the Higgs field and boson.

Higgs

• How the Higgs Field (Actually) Gives Mass to Elementary Particles One effect of the Quantum Field theory is the need for a field to explain Mass. This has been named the Higgs Field and, with great fanfare, in 2012 the discovery of the Higgs particle was announced. Nothing much else was described although lots of philosophical theorizing was generated.