Does anybody know the name of this plant from the Canary Islands?

Hi, my name is Sarah-Therese Mann and I am a Master's student at the UIB in Spain. I am conducting a study about eye-witness memory and language. Therefore I am looking for native speakers of English and German. Are here any participants? It would not take long and I would appreciate your help!

Here is the survey for English native speakers:

This discussion is not about contradicting SR, GR, or 4D spacetime. We do not believe in SR or 4D spacetime, we have seen them too many times, we have seen SR work in accelerated motion, provide the basis for GR, and for quantum mechanics, in hundreds of applications, including MRI.

These are the points of discussion here: (a) Why take the 4D spacetime formulations as the preferred choice in SR? and, (b) Do the 4D spacetime formulations form a coherent body, a corpus, that we can use?

We provide some answers to these two questions, for discussion.

IINTRODUCTION

Different formulations of special relativity (SR) exist, such as by Minkowski [1], by Burgess [2], the original formulation by Einstein [3], by Mashoon [4], by Taylor and Wheeler [5], all different, as our different views of reality. Also, such as Clifford(3,1), where one can accept SR but not 4D, considering 3D +1D. Or, even Newtonian mechanics, only with 3D and time as absolute.

Here, we see all of them as right, but having different regions of validity, ordered as 4D ⊃ 3D +1D ⊃ 3D, in set theory, a fundamental theory in maths.

In other words, the other theories with less dimensions are all grandfathered in 4D spacetime, even those not mentioned, with nothing to discuss in that aspect.

Also, the question answers a common, cornucopia of questions of someone who begins to study SR, even in most US universities and colleges, for example, and is taught along the original formulation by Einstein [3], which is inconsistent and incomplete. The Lorentz transformation is introduced as a first-fiddle in [3], not as consequence, as in [1,2]. This creates most problems.

HIGHER LEARNING

Students may think, as reported many times, and in RG, that SR only applies to inertial motion. But, acceleration does not shut-off length contraction or time dilation. While students are fortunate to escape "relativistic mass" (not used by [3] but used originally by Einstein), they do not usually escape "rest mass".

SR as spacetime, applies to ARBITRARY motion, but we see that students are still, 100 years later, often learning a historical subset of it, and are poorly prepared for GR, taught now in undergratuate courses, that uses the same formulation of spacetime, found in [2], and hinted in [1].

The discussion aims to unite these aspects, showing a coherent body, a corpus, around the Minkowski formulation [1], such as we view today, in [2], of 4D spacetime (see NOTES, 1)

This should prevent questions we found even among researchers and in higher education, well-known professors in the US, Europe, and in RG, such as about the "inconsistencies in SR" -- meaning the first formulations by Einstein, Poincaré, or even 100+ years ago by Minkowski [1]. This us list in time. Physics has evolved out of this quagmire, using it as a support and motivation to escape.

Today, the formulation by Burgess [2], for example, would clarify most questions in SR and GR. For example, that SR and GR are not independent. There is value, for some students, to learn them at the same time, the spacetime is the same, the metric changes.

Or, about the source of magnetism, which is due in SR 4D spacetime today to the movement of charge, only. This, particularly prevents a student from thinking, a la Maxwell and Faraday, that magnetism is somehow independent from electrostatics, and also shows why MKS is not used here -- the units must be the same for B and E.

Other difficulties exist, such as listed in the growing list in [6], also [6-9]. Someone, for example, could also not avoid gimbal lock in 3D rotations, but that becomes easy in 4D [9].

While this discussion is more comprehensive, we list as important, but superfluous, some apparent stumbling blocks in gauge theories, and quantum mechanics -- use of the Schrödinger equation, the use of Clifford algebra in physics, such as STA and Cl(3,1), and other preventable problems. Participants are iinvited to add their favorite misconception, or other candidates for corpus.

Thus, formulations of the SR may change, and many had now comic misconceptions, such as "relativistic mass", whereas many points in the SR, as a corpus, are considered experimentally confirmed beyond reasonable doubt, described in 4D spacetime.

MINKOWSKI

It was Hermann Minkowski (Einstein's mathematics professor) who announced the new four-dimensional (spacetime) view of the world in 1908, which he deduced from experimental physics by decoding the profound message hidden in the failed experiments designed to discover absolute motion. Minkowski realized that the images coming from our senses, which seem to represent an evolving three-dimensional world, are only glimpses of a higher four-dimensional reality that is not divided into past, present, and future since space and all moments of time form an inseparable entity (spacetime). [1] ff.

Einstein's initial reaction to Minkowski's view of spacetime and the associated with it four-dimensional physics (also introduced by Minkowski) was not quite favorable: "Since the mathematicians have invaded the relativity theory, I do not understand it myself any more.“

However, later Einstein adopted not only Minkowski's spacetime physics (which was crucial for Einstein's revolutionary theory of gravity as curvature of spacetime), but also Minkowski's world view as evident from Einstein’s letter of condolences to the widow of his longtime friend Besso: "Now Besso has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion." Besso left this world on 15 March 1955; Einstein followed him on 18 April 1955.

Turning to the ontological question, what is place in the scheme of things in nature, of SR 4D spacetime: maths or physics?

Is 4D spacetime just a use of mathematics, or does it represent nature in ways that using lesser dimensions just can not do? Is 4D spacetime like a spreadsheet of calculations, not really nbecessary, for a reality that is entirely experienced as 3D +1D, or even 3D with time as a parameter?

Names seem to not matter, as expected, in physics. it would seem that it does not matter, then, if someone, for example, chooses a geodesic to extend Newton's First Law, overcome beautifully our limitation then (to define "straight line"), and designates it as an extended "inertial motion" -- the geometric basis is the same, the physics did not change. Or, like Mashhon, describe an infinte family of comoving observers, 3D, each one as a flash in time. One would seem to need less mathematics, it can all be solved in 3D +1D, even 3D, not needing 4D. But the context is just more limited, the region of validity is less, as we show next.

It is physically limiting to use names that do not distinguish curvature as stretching (as done in 4D spacetime), only considering curvature as bending. The spacetime that was being considered is flat, it can be seen in 3D like a stretched, flat pizza dough. The spacetime is flat but if the world trajectory is curved, it still fits with curvature as intrinsic, as stretching, so not just world straight lines "fit" in flat spacetime!

The 4D spacetime, in SR or GR, therefore, works for world-curves, as they may curve, in the world we see as flat spacetime, locally, as SR, or curved spacetime, as we see in GR. Only the 4D spacetime formulation of SR and GR can do that, we cannot use lesser dimensions, may be more.

The visible world, however, as viewed, is NOT 4D spacetime, it seems at first sight. The world is apppearing to us as 3D +1D, or 3D plus time as parameter. But, the world is governed in 4D spacetime, which manifests itself through laws that 3D or 3D+1D cannot represent, but we can see in everyday experience -- just like we do not see the Earth going around the Sun, we see the Sun going around the Earth, apparently, but we do have seasons, and the ancient Greeks measured the circumference of the Earth, with no rockets, quite correctly, through mathematics.

Therefore, the relatity, the world we live in, the truth-conditions, is at least 4D. Some just experience life less, as 3D+1D, or 3D, or even 2D. But the mechanism works in at least 4D, and 3D cannot represent it, as shown in SR and GR experiments. For example, with length contraction or time dilation for non-comoving observers, only.

Therefore, there is no ontological status anymore, and this is beautiful, not just right. This is also, perhaps, new to philosophers.

CONCLUSION

We suggest that a consistent picture emerges supporting Minkowski's view [1,2,] with no ontological question. This includes Einstein, who first rejected it publicly, at first intellectually stymied, as with the now-called Hubble flow in Cosmology, but confimed it, mathematically expanded on it, and used it further in physics, in his theory of general relativity. We are all working in cooperation, even those who do not seem to cooperate, do -- they promote patience, discussion, new ideas, new values.

PAUSE. If your notion of SR does not work with accelerated or arbitrary motion, OK, do not panic; spacetime is SR that is valid (works all the time) for accelerated motion, for non-inertial, ARBITRARY, reference systems.

Here, one should try and clarify any questions first with the discussion text itself, and then with the references by Burgess or Wheeler, cited next -- guessing definitions may not interwork!

Note that comoving and non-comoving, as well as length contraction and time dilation, are not "just words" or optical illusions -- what they denote can cross a barrier, can produce thermodynamic work. They define different physics, different truth-conditions, not just different truth values.

This may change according to the formulation of SR one uses, but we suggest that [1,2] can offer a consistent view. Later on, SR and GR can be complemented with Cosmology, and Hubble flow, without contradictions, even when comoving points separate in inertial motion, and galaxies move faster than light [7 ].

As a result, may also the rigid time in undergraduate courses [8] be better spent. Someone, for example, could also not avoid gimbal lock in 3D rotations, but that becomes easy in 4D [9].

The SR as a 4D spacetime so described, is more and more, seen in all sciences, fitting the original name of a "theory of invariants". Building a verified, coherent, corpus supporting [1] in 4D and (not only) modern variants such as [2] -- which we examine in this discussion, below, where other researchers are invited to add their views in the answers.

1. In SR and GR spacetime, accelerated motion is defined absolutely, for example, with no absolute reference system or geodesics, of course, by extrinsic and intrisic geometric properties of the curvature.

So, it does not matter if someone chooses a geodesic to extend Newton's First Law, overcome beautifully our limitation then (to define "straight line"), and designates it as an extended "inertial motion" -- the geometric basis is the same, the physics did not change, the context is just more limited.

It is limited to not distinguishing curvature as bending, only considering curvature as stretching, in spacetime -- the spacetime that was being considered is flat, like a stretched, flat pizza dough. The spacetime is still flat if the world trajectory is curved, not just world straight lines "fit" in flat spacetime!

It all works for geodesics, world-curved as they may in the world we see as flat spacetime, locally, which is NOT spacetime but governed by a flat spacetime, there is no ontological status anymore, and this is beautiful, not just right. This is also, perhaps, new to philosophers.

But... it does not work in GR, under free fall in a gravitational field, because the spacetime is curved under gravity, as bending. So, inertial motion must be redefined, not as a name, but as a truth-condition. This is how GR actually exists, we are NOT reinventing the wheel, just may be going a bit further into what GR means, not just what it says.