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Welcome - Einstein's relativity - The ether - Galileo's relativity - Waves - References

Don't laugh, he is one of the greatest scientists of his time, his teacher, Plato, had nicknamed him "intelligence", he was the tutor of Alexander the Great, which says a lot about his notoriety and whose exploits of his student are partly due to him. He has demonstrated very intelligently that the Earth is stationary, and therefore that the Sun and the planets revolve around it. Aristotle was trapped by the relativity of motion, a principle he did not know.

Aristotle's other mistake will be to say that heavy bodies fall faster than light bodies and to classify his five elements from the heaviest, earth to the lightest, ether, passing through water, air and fire. In any case, these elements did not make sense, as chemists would show over time.

Giordano Bruno, a powerful and observant mind, noticed that an object that fell from the top of the mast of a boat moving in a good breeze, fell at the foot of the mast and not at the back of the boat which continued to move forward during the fall. He realized that this undermined Aristotle's demonstration of the Earth's immobility.

This discovery and his ideas about an infinite universe as well as his vision of religion led the Roman Catholic Apostolic Church to condemn him to be burned alive in 1600. In the name of a god who would be the father of us all and would love us all as his children!

For his part, Johannes Kepler took up the work of Copernicus, benefited from the very precise measurements of the position of the planets made by Tycho Brahe before his death and led to elliptical orbits around 1609.

Galileo and his students verified that if the marble travels one unit of distance first, for one unit of time, it travels 3 for the next unit and then five for the next unit, which gives for units 1, 2, 3 the progression 1, 4, 9. It is a uniformly accelerated movement whose distance traveled is proportional to the square of the elapsed time.

Inclined plane visible at the Galileo Galilei Museum in Florence

https://florencesite.fr/musee_galilee.html

"Movement is like nothing". The fact that a falling object continues to move horizontally at the same speed, he describes a parabola, led him to state the principle of relativity:

The article on relativity was rejected by the scientific community. The reasons for this rejection had nothing to do with the person of Albert Einstein since his three other papers were well received and his thesis that he passed in 1906 which gave the size of the molecules and made it possible to calculate the Avogadro number was also appreciated. Of course, there were people with bad intentions or who hated Einstein who took advantage of the situation

This situation may be surprising, but it surprised us. To avoid any misunderstanding, here is the version translated into French that respects the original one in German:

The speed of waves is independent of the speed of the objects that produce it, an aircraft can catch up with the sound it produces and even exceed it, but it depends on the characteristics of the medium that propagates them. Einstein in the wake of this eliminates the ether, the medium that fixes the speed of electromagnetic waves and which a priori would prevent these waves from having the same speed in all reference frames. We say a priori because we have a hypothesis on this question. A hypothesis that at first glance seems absurd, but which is made possible by general relativity itself. Having found no one to listen to us, we thought it important to clear the ground of misunderstandings about this exceptional theory. You should begin to understand the reasons why it was criticized even by the greatest physicists of the time.

Our goal is to consolidate it with regard to this speed of light, which would be the same everywhere, which would contradict the relativity of its motion if there were no other condition to be fulfilled.

It uses synchronized clocks at both ends. An observer emits a ray of light from point A at time tA, which is reflected at point B at time tB and which returns to A at time t'A. Observers check the immobility of clocks that have not moved during the measurement and find a value

In accordance with the experiment, we will therefore make the assumption that the magnitude
is a universal constant (the speed of light in empty space).

* Einstein uses V for the speed of light, c will be used later *

- a) The observer with the measuring rod moves with the measuring rod and measures its length by superimposing the ruler on the rod, as if the observer, the measuring ruler and the rod are at rest

- b) The observer determines at which points in the stationary system are the ends of the rod to be measured at time t, using the clocks placed in the stationary system

Here Albert Einsteins' explanations are a little tricky to follow. We have made a diagram. The observer is in the frame of reference K and the rod in k in motion at the speed v

From K we see the light at the speed V chase the point B which moves away at the speed v. the light ray takes longer to reach B Einstein writes on the return the point A approaches at the speed v and therefore:

where rAB is the length of the moving rod, measured in the stationary system. (K)

font-size=2>Translator's note: Here, the term "time" refers interchangeably to "time in the stationary system" and "position of the hands of a moving clock" located at the position in question

Einstein takes up the case of paragraph 2 where we have dissociated the two frames of reference for greater clarity. We will present the way in which Einstein establishes his equation linking the coordinates of the two frames of reference and use variations that tend to 0 for the calculations, calculations that we will not detail and which lead to the same transformations as those of Lorentz.

Let us measure the space with the ruler and clocks of the stationary system K, with coordinates x, y, z and time t, those of the ruler in the coordinate system k moving at the speed v which will be x, y, z and time

If we set x' = x - vt, then for a point at rest in the system k, there is a time-independent system of values x', y, z.

We translate that there is a point x' of K which at time t coincides with

Let be a ray of light sent at time τ0 from the origin of the system k along the x-axis in the increasing direction of x' and which is reflected at the point B at time τ1 towards the origin of the coordinates, where it arrives at A at time τ2.

So, we have

If we introduce as a condition that τ is a function of the coordinates, and apply the principle of the constancy of the speed of light in the stationary system, we have

At time t, we have time t0 at position x=0, y=0, and z=0. The time font face="Symbol">t2 is measured at the time t2 and t2

Continuing the calculations, which we will not detail here, he finds the same transformations as Lorentz, finalized by Henri Poincaré. There is no plagiarism since he does not use the displacement of the Earth at 30km/s in the reference frame of the ether which he does not need. He uses the postulate that light propagates in empty space, at a speed V independent of the state of motion of the emitting body.

We promised to explain why Albert Einstein finds the same values as Lorentz. It's very simple, you just have to draw the arm of the interferometer which is parallel to the movement of the Earth, and which is made up of a rigid rod AB equipped with a semi-reflective mirror inclined at 45° in A and a mirror that reflects light in B.

A ray of light is sent parallel to the rod AB, at A it splits in two, and while the ray perpendicular to AB will bounce off a mirror located at the distance AB, the undeflected ray goes to B, from where it is reflected to A.

It should be noted that the interferometer arm parallel to the Earth's displacement leads to the same measurements and transformation to explain the lack of detection of the Earth's motion in relation to the supposed reference frame of the ether.

We find the same motion proposed by Einstein for the rigid bar AB and therefore the same equation as Einstein's for which the interferometer must not detect any variation. Hat.

Einstein said that he had the "happiest idea of his life"5 in 1907, when he realized that in free fall, we do not feel our own weight, we do not feel subject to any force, we float in the void and the objects that accompany us are immobile in relation to us.

No physics experiment carried out in this frame of reference distinguishes this state from that of an inertial frame of reference far from any gravitational field. This makes free fall a relative movement that cannot be detected in the absence of external landmarks

Newton's "cannon" allows us to understand free fall: the shell is in free fall, its speed allows it to travel through a parabola before falling to the ground. At a high speed it is satellited and at the escape velocity, it escapes the Earth's gravitation.

Einstein places himself in the position of the observer. Seen from Earth, we see the celestial bodies revolving around us.

Incidentally, he justifies Aristotle's error, in the free-falling frame of reference of the Earth he could not detect its motion by a local experiment.

He makes another discovery apparently related to the operation of elevators. When going up, when starting you feel slightly packed, it's due to the acceleration of the cabin. On the descent on the other hand at the beginning we are lighter, it is still due to the acceleration of the cabin but which at this moment is negative in relation to the Earth's gravitation and suddenly decreases it.

Einstein deduced that acceleration was equivalent to gravitation

Acceleration and gravitation are equivalent

It has a particular characteristic that we have discovered that would allow us to formulate a bold, bold but simple hypothesis that is relatively easy to verify. It also has the great advantage of being able to be formulated using only what Albert Einstein wrote. This hypothesis is rightfully his.

It is up to you to decide whether you want to know her or not. We have published a book which explains this hypothesis and the means of verifying it with experiments. If you could buy this book and talk about it to friends, physicists if possible, in order to make known this hypothesis which seems absurd at first glance and which uses the word ether to which for a moment, from 1920 to 1936, Einstein considered existence and then abandoned for lack of having or attributing to it a motion that agrees with relativity. Overcoming the hurdle of the word ether will be the most difficult, I speak from experience. In the end, it is general relativity that explains the mysterious motion of the ether and at the same time makes it compatible with relativity but can ultimately be explained in a simple way. Thanks in advance.

https://librairie.bod.fr/lether-quantique-dalbert-robert-j-9782322521401

https://librairie.bod.fr/the-ether-of-albert-einstein-robert-jobard-9782322455959

Albert Einstein

Isaac Newton

Galilée