Inertiels

Inertiels are a hypothetical class of elementary entities proposed in speculative physics to account for the origin of inertia or to serve as components in modified gravity theories. The term is a neologism derived from inertia, used to describe fields or particles that interact with spacetime in a way that yields a resisting force to acceleration beyond conventional mass-energy effects.

In theoretical models, inertiels may be described as gauge-like fields that couple to the metric or affine connection. They are often posited to be nearly massless and to become dynamically relevant only in accelerated frames, producing inertial effects through their configuration in spacetime. The mathematical formalisms vary: some treat inertiels as excitations of a background scalar or vector field; others as emergent quasi-particles arising from deeper Machian or entropic considerations.

As yet, inertiels have no empirical support. Their existence remains speculative and primarily discussed in theoretical papers or science-fiction inspired models. Experimental constraints from precision tests of the equivalence principle, free-fall measurements, and cosmology place limits on possible couplings and energy scales. If real, inertiels could offer alternative explanations for inertia or serve as components in modified gravity theories that aim to address cosmological observations without dark matter.

Related ideas include Mach's principle, the inertia–mass relationship, scalar and vector field theories, and emergent gravity scenarios. The term remains controversial and is not part of standard physics. See also inertia, Mach's principle, and modified gravity theories.