A New Perspective on Space-Time: The Shuttle and Missile Objection
Introduction
My approach does not fundamentally require validation from current science, since it simply builds upon space-time diagrams already recognized by it. It only demonstrates, in an irrefutable way, that science, since the birth of Special Relativity, has not fully carried through its interpretation of things. Indeed, taking into account the existence of bodies in certain of these diagrams leads to contradictions. This necessarily compels a reconsideration of the postulate of the invariance of the speed of light. Thus, the need for a new conceptual framework for physics comes into view.
The Shuttle and Missile Objection
The spacecraft’s trajectory is presented here in blue, its line of simultaneity just before accelerating is colored brown, and its line of simultaneity just after accelerating is colored green. It can be seen that during the acceleration phase, the spacecraft’s line of simultaneity has undergone a rotation. The place where the missile base is located is indicated by the event "launching of the missile" indicated on the left by a picture of a small missile. The curved shape of the spacecraft’s trajectory due to its acceleration shows that the spacecraft is traveling at 50 per cent of the speed of light with respect to the launching pad, taken as the fixed reference value. For the sake of clarity, high spacecraft speeds have been depicted on the diagram, but this objection would be valid even at lower speeds, in which case one would have to take a larger distance from the missile base to the spacecraft. It can be seen that the "launching of the missile" event is taken by the spacecraft to have taken place both before its own acceleration, since it is placed below the brown line of simultaneity, and to have taken place only after its acceleration, since it is placed above its new line of simultaneity (the green line). This does not seem to be very plausible if we have accepted the existence of the missile on the basis of the spacetime diagram and the principle of the relativity of simultaneity at the physical level. If the spacecraft’s control system has started before accelerating to perform a three-dimensional calculation of the missile’s spatial trajectory, it cannot possibly assume after accelerating that the missile does not yet exist (the missile is taken in this thought experiment to be assembled only at the very instant at which it is launched). There do not exist two universe lines corresponding to the trajectory of the missile on the spacetime diagram:. Here we are talking about a three-dimensional calculation of the missile’s trajectory, which would be contradictory to what is shown on the spacetime diagram. The principle of the relativity of simultaneity at the physical level suggested by the invariance of c therefore results in a contradiction (1), and since there is no third possibility, absolute simultaneity must be what exists at the physical level. And yet it has been established here that if there was absolute simultaneity, the speed of light could not be invariant in all possible cases involving inertial observers. This amounts to challenging the validity of the second postulate proposed in Einstein’s theory of special relativity.
Note 1: The principle of the relativity of simultaneity at the physical level, as derived from the invariance of c and highlighted by the shuttle and missile objection, proves to be self-contradictory. It indeed suggests that what exists relative to the spacecraft (the missile) has subsequently not yet actually existed. The fact that the two events are separated by a space-like interval does not in any way affect the validity of this statement.
Consider a missile located 1 kilometer away from a spacecraft: if it has already traveled 100 meters after being launched, this remains a fact, regardless of whether the spacecraft accelerates or not. Now, if the missile is much farther away (for instance, billions of kilometers), and if it has also traveled 100 meters after being launched before the spacecraft begins to accelerate, The problem remains the same.
However, according to the theory of relativity, by applying the principle of the relativity of simultaneity, the temporal order of the two events — "launching of the missile" and "onset of the spacecraft’s acceleration" — can be reversed. By proportional calculations linking the spacecraft’s acceleration and the distance between the spacecraft and the missile, one could conclude both that the missile has already traveled 100 meters before the spacecraft’s acceleration and, in another frame, that the missile has not yet been launched after the spacecraft has accelerated.
This implies that if the spacecraft’s control system takes the existence of the missile into account, it would arrive at two contradictory results regarding the position, and even the existence, of the missile. There is no need to have all the equations of relativity at hand to follow this reasoning. It is enough to realize, first, that the invariance of the speed of light implies the principle of the relativity of simultaneity at the physical level (Claim 1), and second, that in view of the shuttle and missile objection, this principle is self-contradictory (Claim 2). Since we are in a spacelike interval, the shuttle pilot cannot perceive the event "missile launch." But in the thought experiment, we do not need to know whether the missile was actually launched. The reasoning is as follows: if the missile was indeed launched at that moment, the consideration of this event with this space-time diagram leads us to a contradiction.
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Validity of this interpretation of the space-time diagram:
It is important to keep in mind the objective of the shuttle and missile objection: to demonstrate that the speed of light cannot be physically invariant during a one-way journey between two points, in all cases and for all inertial observers (sense 1). One may also consider the invariance of the speed of light in the case of a round-trip journey (sense 2). This distinction must be carefully specified; otherwise, the discussion risks addressing different issues. For the speed of light to be physically invariant (sense 1), it is necessary to assign a physical meaning to the lines of simultaneity by associating them with the existence of moving bodies. This amounts to recognizing the existence of bodies as it is revealed in the space-time diagram, which justifies a specific interpretation of the diagram, directly linked to the purpose of the demonstration. My reasoning is solely aimed at establishing that the speed of light cannot be physically invariant in all circumstances (sense 1). While some might consider this point minor, it is in fact a significant advance, as it could foster an evolution in our conception of space-time and open the way for new experimental investigations. Challenging the physical invariance of the speed of light (sense 1) would thus promote a more realistic interpretation and could lead to a renewal of the conceptual framework of physics.
It was ThM, from the forum Physique Oline, who provided me with the first space-time diagram representing my shuttle and missile objection. However, during the discussions, it was not acknowledged by ThM that the postulate of the invariance of the speed of light implies the principle of the relativity of simultaneity at the physical level, and that this principle requires, in the shuttle and missile objection, to take into account the existence of the missile based on what is shown on the space-time diagram. Indeed, it is precisely from this consideration that the validity of my objection becomes evident. ("Principle of the relativity of simultaneity at the physical level": see the chapter "Einstein’s Misinterpretation in his Train Thought Experiment" - assuming the invariance of the speed of light (sense 1) - in the book “And He Was Hovering Over the Waters: Toward a New Vision of the Physical World ?”.)
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Note on Terminology: In this discussion, "the relativity of simultaneity at the physical level" means that the relativity of simultaneity, as stated by Einstein, corresponds to a real event in the physical world, and not merely to a way of measuring or representing phenomena. (on this subject, see the chapter mentioned above)