*Reference: **Disturbance Theory*

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In Newtonian mechanics, the motion of a body (of constant mass) is defined by its velocity. In its default state, a body drifting in space at uniform velocity may be subject to forces, such as, gravity, but all those forces are in equilibrium.

Per Newton’s Principia for the Common Reader, the Newton’s Laws of Motion are,

*Law I: Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.*

*Law II: The change of motion is proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed.*

*Law III: To every action there is always opposed an equal reaction: or, the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.*

Thus, the uniform drift velocity of a body in space does not change, unless its state of equilibrium is changed by some external force. Newton states,

*“The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.”*

The default uniform velocity of a body is maintained by its innate force of inertia, which keeps it in equilibrium.

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## MRF & Inertia

Per Newton’s second law, the force necessary to change a body’s velocity is proportional to its mass. The more is the mass of a body, the greater is the force required to disturb its uniform drift velocity. Thus mass provides inertia to the body.

**The mass of a body acts as inertia that maintains its uniform drift velocity.**

In the MRF (material reference frame) the uniform velocity is considered relative to the velocities of other bodies, such as the earth and the sun. However, in the SRF (space reference frame) the reasoning allows us to associate absolute rest with infinite mass [see *Reference Frames: MRF vs SRF**]. Thus, the uniform drift velocity of a body may be associated with its mass.*

**The uniform drift velocity of a body must decrease as its mass or inertia increases. **

Mass not only increases with density, but also with bulk. The mass of an atom increases throughout the periodic table.

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## SRF & Inertia

The concept of inertia has been confined to matter as it was the only condition of substance known in Newton’s time. With Einstein the concept of substance has now been extended to include electromagnetic “energy”. Since inertia is a fundamental concept associated with matter as substance, we may extend it further to electromagnetic “energy” as a property of substance. Thus, SRF highlights a dimension of inertia that is not so obvious in MRF.

**Inertia describes how substantial a substance is. **

In SRF, the frequency increases throughout the electromagnetic spectrum, and collapses as mass at the upper end. Frequency and mass are equivalent properties of substance. The concept of inertia as substantial-ness shall apply to both frequency and mass. What happens with mass in MRF may be generalized as happening also with frequency in SRF. We may sum it all up as,

**Velocity decreases as the inertia (indicated by frequency or mass) increases.**

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## Inertia & Quantization

In his very first paper published in 1905 Einstein established the concept of “energy quanta” or “light quanta”. The manifestation of light quantum (photon) becomes more pronounced as the frequency of electromagnetic energy increases [*see ***Einstein’s Paper on Light Quanta (1905)***]. *Einstein received Nobel Prize for this discovery.

Einstein thus introduced quantization as the phenomenon of increasing inertia. A continuous function at low frequency increasingly becomes discrete at higher frequencies. This is accompanied by the electromagnetic “substance” becoming more compact and durable.

This brings to mind a contour map where elevations are marked by contour lines, and where contours of higher elevation appear within the contours of lower elevations. In the case of electromagnetic field, the contours of higher frequencies shall appear within the contours of lower frequencies as the field becomes more compact with increasing frequency. Compactness indicates higher inertia.

**Regions of higher inertia appear to be discretely placed within the regions of lower inertia of the field. **

This may explain the transition from continuous electromagnetic field to discrete matter in SRF.

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## Further Research

The SRF thus introduces the dimension of inertia in which MRF occupies a very small portion at the higher end. On this dimension the basic substance of the field transitions from continuity to discreteness. This is understood as quantization. Quantization seems to contribute rapidly to inertia.

The next step is to explore the process of quantization and how it contributes to inertia.

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