Inertia

In physics, inertia (from the Latin inertĭa) is the property of bodies to remain in their state of rest or relative motion. Said, in a general way, it is the resistance that matter opposes to a change in its state of movement, including changes in speed or in the direction of movement. As a consequence, a body maintains its state of relative rest or relative uniform rectilinear motion if there is no force that, acting on it, manages to change its state of motion.

In nature there is no absolute rest, all matter is always in motion, so when talking about rest or Uniform Rectilinear Motion (MRU) you must add the word "relative" (relating to a reference system). The body is at rest or at MRU only with respect to that reference frame. When a body is at relative rest on the Earth's surface, it is also participating in the different movements that the planet makes if a reference frame centered on the Sun is considered. Likewise, it is subjected to different forces such as the gravitational forces of the Earth. Earth, the Sun, the Moon and other bodies, as well as the mechanical resistance that prevents it from sinking into the earth, or sliding. It can be said that the body is in equilibrium on the surface of the Earth and, therefore, in relative rest.

We could say that it is the resistance that a particle system opposes to modify its dynamic state.

In physics it is said that a system has more inertia when it is more difficult to achieve a change in its physical state. The two most frequent uses in physics are mechanical inertia and thermal inertia.

The first one appears in mechanics and is a measure of the difficulty to change the state of movement or rest of a body. The mechanical inertia depends on the amount of mass and the inertia tensor.

Thermal inertia measures the difficulty with which a body changes its temperature when it is in contact with other bodies or when it is heated. The thermal inertia depends on the heat capacity.

The so-called inertial forces are fictitious or apparent forces that an observer perceives in a non-inertial reference frame.

Interpretations of inertia

Some researchers consider mechanical inertia to be a manifestation of mass, and are interested in particle physics ideas about the Higgs boson. According to the Standard Model of particle physics, all elementary particles are virtually massless. Their masses (and therefore their inertia) come from the Higgs Mechanism via exchange with an omnipresent Higgs field. This leads to deduce the existence of an elementary particle, the Higgs boson.

Others are inclined to view inertia as a characteristic connected to mass, and work along other pathways. The number of researchers who deliver new ideas here is small. Many of the ideas put forward in this regard are still regarded as protoscience, but it illustrates how theory formation in this area is progressing.

A recent publication by the Swedish-American physicist C. Johan Masreliez proposes that the phenomenon of inertia can be explained, if the metric coefficients in the Minkowskian line element are changed as a consequence of acceleration. A certain positioning factor models inertia as a gravitational-like effect.

In a subsequent article for Physica Scripta, he explains how special relativity can be compatible with a cosmos with a fixed and unique cosmological frame of reference. The Lorentz transformation models the structure formation (“orphing” of mobile particles, which could preserve their characteristics by changing their local space-time geometries. With this the geometry becomes dynamic and a an integral part of motion. Masreliez says that it is this geometry that changes to be the source of inertia, ergo, to generate the force of inertia. If accepted, inertia could connect special relativity with general relativity., although the inertial frames are still physically equivalent and the laws of physics apply equally, they do not model the same space-time These new ideas, SEC have so far been tested not only by the proponent but also by some members of the scientific community The SEC theory is controversial, as it disproves the Big Bang hypothesis

Another approach has been suggested by Emil Marinchev (2002).