A blue sky, with the WHAT_IS_INERTIA website title


WELCOME to this Website Page part of the Gravimotion websites family.
Gravimotion is a logical (not philosophical) alternative to conventional interpretation of physics' mathematics.
While honoring physics' mathematics, gravimotion's main feature is to make sense!


Please forgive, when awkward, the English of this page. English is not the author's native language.
Average Reading Time: 3 minutes 30 seconds

Inertia is made of 2 discordant concepts in physics science

Inertia is a heavy weight in physics!

Physics concept of inertia
                is a heavy weight that
   has to be dragged around !

Here is Newton's first law, known as the inertia law:
Any object in the state of rest or in the state of uniform motion, remains at rest or in uniform motion, unless acted upon by an unbalanced force.
Clearly speaking, there is no unbalanced force in the direction of uniform motion when such motion occurs.
The uniform motion of any material body is implicitly maintained by that body's inertia; hence that "inertia law" traditional name; and Newton's 2nd law concurs, inertia impedes any acceleration and any deceleration.

This inertia law is in conflict with constant spin
Because it constantly changes direction, a spinning object such as a top or the earth is not in uniform motion.
As such constant spinning is not taken care of by the inertia law, even though it is inertia that maintains constant spinning!

Note that friction slows down the spinning of the toy. Similarly due to the moon, which causes the tides, Earth's spin is slowed down through friction of water flows. Friction though, and not inertia, causes the slowing.

Physics solution: create a mathematical duality
In order to comply with Nature, physicists created another law besides the inertia law!
The new law involves angular speed, angular momentum and rotational inertia!
Clearly the rotational inertia has nothing to do with the inertia law!
Now there are two drastically differing concepts of inertia in physics.

The one-ness of inertia in reality
We can only imagine the reality of inertia as being one.
As a matter of fact physicists did not invent a new word to label the inertia that maintains constant spin.
Physicists only gave it the rotational adjective; there is only one inertia in Reality.

First Observation
Because there is only one inertia in reality, physics' duality of inertia (inertia law / rotational inertia) departs from the unity of Nature.
And because inertia is at the base of all of physics, physics is now based on two differing pillars, and that seems to compromise the unity of any subsequent buildup no matter how elaborate or clever!

Inertia Fundamental Problem

Besides physics' 2 mathematical concepts of inertia, the 1st being incompatible with the 2nd because of the direction factor, there is a much more troubling problem wedged deep within our very concept of inertia!
In our concept of inertia this other concept of ours, which is time plays no role!
In physics, inertia (as well as mass by the way) exists independently of our concept of time!
Yet since Einstein revelations, we know that space and time make one!
Because mass, and our concept of inertia integral part of mass, occupy a finite volume of space, according to Einstein thoughts, mass and inertia should occupy a finite duration of time!
But inertia and mass do not, neither is defined in time.

Second Observation
The absence of time within our concept of inertia prevents us human beings from understanding this specific aspect of Nature.
The very inert characteristic of inertia, which originates in Newton's inertia law, and which appeared plausible up to Einstein, becomes a liability upon the onset of space-time.

To top it all, inertia is a fictitious idea that has no physical collateral

Inertia is not merely a human idea, inertia is a human invention! The bad news is that this inertia invention of ours is an idea that has no physical collateral; proof is there is no unit of measure for inertia in science; inertia which cannot be measured is fictitious!
Gravimotion's interpretation of Nature sticks to that fundamental precept of physics, that any conclusion must be based on factual reality. As such inertia, which is a mental invention with no physical collateral whatsoever, ends up being disregarded in gravimotion.

Comments and an Innovative Alternative

Even though serious, these controversies do not compromise the respect we have for physics
Because empirical, physics' mathematical description of reality is exquisitely accurate.
On the other hand the abstract interpretations, built-up by our human brains on top of physics' mathematics, reach definitely a questionable level.
According to above, our concept of inertia is obviously part of such abstract and questionable interpretation.
There is at least another interpretation of Nature that eludes physics' inertia dilemma.
In that interpretation, called gravimotion, uniform motion takes over and inertia is altogether dismissed as follows:
  • Because inertia is fictitious, and because uniform motion nevertheless occurs, uniform motion must be the cause of itself in reality; and that furthermore entails that uniform motion is a physical entity.
    One way to enter the mental world of gravimotion is simply to recognize first that motion is physical, then that motion is self-sufficient!
Because everything is in motion along the expansion of the universe, a fact Newton was not aware of, the state of rest is no doubt also fictitious and making abstraction of it, the inertia law can be rewritten (in gravimotion terms):

Any object in motion, remains in the same motion, unless other motion merges with that motion, or part of that motion splits!

Clearly Newton's law is all about motion self-sufficiency, and not at all about inertia!
Now viewed from that angle, this law includes the spinning motion of an object as the latter only requires no change in motion to occur.
There is nothing to understand, simply take note of motion self-sufficiency when the law is about motion self-sufficiency!
In a nutshell:
  1. In gravimotion's interpretation of Nature, Newton's 1st law is interpreted literally, in term of motion, as the word inertia doesn't even appear in it.
  2. And because motion is the only entity on which rests gravimotion interpretation of Nature, uniform motion and constant rotational motion become de facto unified.
  3. The state of rest, being incompatible with motion, does not exist in gravimotion interpretation of Nature, just as it does not exist in quantum theory. And that represents another step toward unification.
Gravimotion is a new, unheard of, spectacular yet ignored interpretation of Nature
There is nothing like gravimotion...
And there is nothing to comprehend either. Just see Nature as is!
Regrettably though gravimotion's simplicity works against itself, it is so simple that it is ususally overlooked.
In spite of general apathy, this author does not loose faith, thanks to Leonardo da Vinci who wrote:
"Simplicity is the ultimate sophistication".

Once one enters the mental world of gravimotion, physics' concept of inertia looks clumsy and antiquated...

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