We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high-energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism. In commemorating the first century of the discovery of general relativity by Albert Einstein that was recognized as a triumph of the human intellect, it would be instructive to look through one of its fundamental debates, namely, between the ether and the relativity points of view. Certainly, very vast amount of work have been performed on these subjects and the references given in this compact survey are not obviously a complete bibliography on these topics, and although we provide adequate references, it is a self-contained work. However, while we are trying to spell out some basic issues behind the subject, the work almost provides a brief review in a different perspective about the long history and the situations of the ether and relativity up to the present days. Nevertheless, it has not been only aimed to give just a motivation to research on the issue, and we propose, somehow during the work, to introduce our points of view and prospects on these subjects in a way that being accessible to many physicists and allowing broader views.It seems that it was Descartes who first introduced into science the concept of ether as a spacefilling material in the manner of a container and a transmitter between distant bodies (similar to what that, nowadays, we call it a field) in the first half of seventeenth century [1]. About one generation after him, perhaps one can consider Newton as one of the ether theory pioneers who practically introduced ether into physics. Actually, Newton presented the concept of inertia in the first law (i.e., the inertia law) of his famous three laws of mechanics [2], and in this respect, he considered an inertial frame as a rigid frame in which free particles move with constant speed in straight lines. On the other hand, a free particle is a particle that moves with constant speed in a straight line in an inertial frame; and obviously, this is a vicious circle (or, a logical loop). In another word, it is ambiguous that what thing distinguishes or singles out the class of inertial frames as criteria or standards of non-acceleration from all other frames. Newton, who was also aware of this difficulty, in order to specify the inertial frames from theoretical point of view, employed the idea of absolute * E-mail: m-farhoudi@sbu.ac.ir † E-mail: M Yousefian@sbu.ac.ir 1 space with the aid of the notion of ether. He considered absolute space as a rest inertial fra...
