Masspressure

Masspressure is an informal term used in some discussions to describe the portion of pressure in a material that arises from its mass distribution and the gravitational forces acting on it. It is not a formal quantity in established physics, and its meaning varies by context.

In fluids and solids under gravity, the weight of overlying material compresses deeper layers, contributing to a pressure gradient. This gravity-induced component is often described via hydrostatic pressure, with P(z) ∫ ρ(z) g dz; some writers colloquially refer to this as masspressure, highlighting its origin in mass rather than thermal or chemical effects.

In astrophysics and planetary science, analogous concepts appear as gravitational or self-gravity pressure, where mass density and gravity determine internal pressures. In dense objects such as white dwarfs and neutron stars, other pressure sources, like electron or neutron degeneracy pressure, dominate and masspressure as a distinct term is not used in formal literature.

In relativistic contexts, the energy-momentum tensor includes mass-energy density and pressure as separate components; masspressure is not a standard relativistic term, though the overall contribution of mass-energy to internal pressure is acknowledged.

Because masspressure is not a standard term, its use can be ambiguous. When precision is required, it is better to refer to hydrostatic pressure, gravitational pressure, degeneracy pressure, or thermal pressure, depending on the mechanism involved.

See also: Pressure; Hydrostatic pressure; Degeneracy pressure; Gravitational pressure; Stress; Mass-energy.