I want to chat about special relativity

Dec 19

I'd be happy to chat about special relativity! It's a fascinating topic with some truly mind-bending implications.

What aspect interests you? We could talk about:

  • The core principles (the constancy of the speed of light, relativity of simultaneity)
  • Time dilation and length contraction
  • The famous thought experiments (like Einstein's train or the twin paradox)
  • Mass-energy equivalence (E=mc²)
  • How it changed our understanding of space and time
  • Specific scenarios or paradoxes you're curious about

Or if you have a particular question or concept you're wrestling with, I'm all ears! What would you like to explore?

Let's start with some general questions. People say that there are no contradictions in special relativity. Do you agree?

Dec 19

I'd say special relativity is internally consistent as a mathematical framework - its equations don't contradict each other. But whether there are "no contradictions" depends on what we mean by that.

Mathematically: Yes, it's consistent. The Lorentz transformations work out beautifully, and you can't derive a logical contradiction from the postulates.

Conceptually: This is where it gets interesting. Special relativity doesn't contain contradictions, but it absolutely contains things that seem contradictory to our everyday intuitions:

  • Each observer genuinely measures the other's clock as running slow (symmetrical time dilation)
  • Two events can be simultaneous in one frame but not in another
  • A moving object is both "actually shorter" from one perspective and "actually not shorter" from its own

These aren't contradictions - they're just radical departures from our intuitive notion that there's one objective "now" or one "true" length. The resolution is that things like "now," "length," and "duration" are frame-dependent, not absolute.

The apparent paradoxes (like the twin paradox) all resolve when you carefully account for reference frames, acceleration, or the relativity of simultaneity.

So I'd say: no contradictions, but plenty of initially counterintuitive results that require us to abandon some deeply held assumptions about space and time.

What's your take? Are there particular scenarios that strike you as contradictory?

Yes. According to relativity, it is only the relative velocity that matters. You get the same measurements by a stationary observer of a moving object as a moving observer would get of the same object if stationary. This, after all, the same as switching inertial frames of reference and they are all equivalent. Agreed?

Dec 19

Yes, I agree with that - it's one of the core principles of special relativity! This is the principle of relativity itself: the laws of physics are the same in all inertial reference frames.

So if observer A is moving at velocity v relative to observer B, then:

  • A measures B's clock as running slow by the same factor that B measures A's clock as running slow
  • A measures B's objects as length-contracted by the same factor that B measures A's objects as contracted
  • There's complete symmetry

You can always switch which frame you call "stationary" and which you call "moving" - it makes no physical difference. The relative velocity is all that matters, not any absolute motion.

This symmetry is what makes scenarios like the twin paradox so initially puzzling - if each twin sees the other's clock running slow, how can one end up younger? The resolution is that perfect symmetry only holds for inertial (non-accelerating) frames. The moment one twin turns around, they break the symmetry by accelerating.

But yes, for purely inertial motion, it's completely symmetric. Where are you going with this? I'm curious if you're building toward a particular scenario or puzzle!

Back in the day, it was assumed that the effect of length contraction could be accounted for by the transformation of the electrostatic forces associated with the moving object. No contradiction here, except for the improbable result that in the limit of lightspeed any object becomes as flat as a pancake. Right?

Dec 19

Yes, that's right - there's an interesting history here!

In the early days (Lorentz, FitzGerald), length contraction was indeed conceived as a physical effect - the electromagnetic forces holding matter together would literally compress an object in the direction of motion. Lorentz derived the contraction formula this way, treating it as a dynamical consequence of how fields transform.

Einstein's breakthrough was reinterpreting this: length contraction isn't about forces squishing objects, it's a kinematic effect arising from the structure of spacetime itself. It's about how we measure lengths across different reference frames, not about physical compression.

As for the "flat as a pancake" limit - yes, as v → c, the Lorentz contraction factor γ = 1/√(1-v²/c²) goes to infinity, so length in the direction of motion approaches zero. But this isn't really a contradiction because:

  1. Massive objects can't reach lightspeed (would require infinite energy)
  2. For photons that do travel at c, the notion of "their rest frame" doesn't exist - there's no frame where a photon is at rest

So the "pancake limit" is more of a mathematical artifact of pushing the formula beyond its physical domain.

But I sense you're building toward something specific - what's the contradiction or puzzle you're seeing?

The idea of relativity is that the effect is not a function of which frame is moving, so did they ever reconcile the fact that a non-moving object shrinks for the benefit of a moving observer?

Dec 19

Ah, now I see where you're going - this is a great question that gets at the heart of what length contraction really means.

The reconciliation is this: the object doesn't "shrink" in any absolute sense. Length contraction is not something that happens to the object - it's about the relationship between the object and the observer's measurement procedure.

Here's the key insight:

  • In the object's own rest frame, it has its proper length L₀ and always has that length
  • In a frame moving relative to the object, measurements yield a contracted length L = L₀/γ
  • But this measurement involves simultaneity - you're measuring where both ends of the object are at the same time in your frame

The "same time" in your frame is NOT the same as "the same time" in the object's frame (relativity of simultaneity). So you're essentially comparing the positions of the two ends at events that the object considers non-simultaneous.

The symmetry is preserved because:

  • Observer A measures object B as contracted
  • Observer B measures object A as contracted
  • Each is correct in their own frame
  • Neither involves the object "actually shrinking" in some absolute sense

It's not that the moving observer causes the stationary object to shrink - it's that length itself is frame-dependent, just like "now" is frame-dependent.

Does this address your concern, or are you seeing a deeper asymmetry here?

My concern is that when multiple observers, moving at different speeds, all attempt to measure the stationary object, they all get different measurements.

Dec 19

Ah yes - now we're getting to the really interesting part! You're absolutely right that different observers moving at different speeds will all measure different lengths for the same "stationary" object.

So we have:

  • Observer at rest relative to object: measures length L₀
  • Observer moving at 0.5c: measures length L₀√(1 - 0.25) = 0.866 L₀
  • Observer moving at 0.9c: measures length L₀√(1 - 0.81) = 0.436 L₀
  • And so on...

All of these measurements are equally valid. There's no "true" length - or rather, each measurement is true in its own reference frame.

This seems bizarre because we're used to length being an intrinsic property of an object. But special relativity says: length (and time, and simultaneity) are not intrinsic properties - they're relational properties that depend on the reference frame.

It's analogous to asking "what direction is the object moving?" - there's no absolute answer. It's moving north relative to one observer, stationary relative to another, south relative to a third. All are correct.

The question is: does this multiplicity of measurements bother you because it seems to undermine objectivity? Or is there a specific contradiction you're seeing when all these different observers compare notes?

Well, I guess that depends on how you define contradiction. The problem, as I see it, is that measurements LIE.

Dec 19

Now we're getting to something philosophically profound! You're right to be troubled by this.

If we define "measurement" in the classical sense - as revealing an objective, intrinsic property of the object - then yes, these measurements could be seen as "lies" or at least as not telling us "the truth" about the object.

But here's the thing: special relativity forces us to abandon the idea that length (or duration, or simultaneity) is an intrinsic property of objects. Instead, these are properties of the relationship between the object and the observer's reference frame.

So the measurements aren't lying - they're accurately reporting frame-dependent quantities. The "lie" is in our pre-relativistic assumption that there should be one true length.

But here's where your concern gets really interesting: In the object's own rest frame, it has a proper length L₀. That seems special - it's the length measured when the object is at rest relative to the measuring apparatus. Is that the "true" length, and all others are somehow derivative or less real?

Some physicists would say yes - proper length and proper time have a privileged status because they're invariants (all observers agree on what the proper length is, even if they don't measure it directly). Others would say all frames are truly equivalent.

What do you think - is there something special about the rest frame measurement? Or is your concern different?

I don't believe that the measurement is frame-dependent per se. It is a consequence of a faulty measurement protocol. Measurements are different because they do not encompass the full magnitude of the length. They are merely the cosine projections of intervals in a frame that has rotated away from the reference frame. Einstein described an ideal measuring system of rigid rods and identical clocks that he claimed could be used to measure any interval. Then he showed that after a Lorentz transformation the results did not agree. I claim that his description of placing the rods end-to-end along the axis of measurement is a textbook example of the dot product of two vectors with no included angle. Couple that with the fact that the relative velocity between two frames is characterized by the boost of a Lorentz transformation, and every boost has a gudermannian angle (tilt), and we get v = c tanh(boost) = c sin(tilt). Then the magnitude of a vector in the moving (tilted) frame can only project r cos(tilt) onto the reference frame. But when v = c sin(tilt) the Lorentz factor is sec(tilt). If r' = r cos(tilt), then r = r' sec(tilt) = γr', length contraction as specified by Einstein. The length of the object literally never changes, but the measured shadow is shorter. The measurement is accurate, but it does not represent the whole magnitude, only the real projection.

Dec 19

This is a fascinating perspective, and you're touching on something deep about the geometric structure of spacetime! Let me engage with what you're saying.

You're absolutely right that there's a geometric interpretation of Lorentz transformations as hyperbolic rotations in spacetime, with rapidity (boost parameter) φ where v = c tanh(φ). And yes, the Gudermannian angle relates these: if we set ψ = gd(φ), then tanh(φ) = sin(ψ) and γ = sec(ψ).

But here's where I need to push back on your interpretation:

The "rotation" in spacetime is not a rotation in ordinary 3D space - it's a hyperbolic rotation mixing space and time coordinates. The geometry is Minkowskian (with signature -+++), not Euclidean.

When you say the measurement is "merely the cosine projection," you're suggesting that:

  • There's a "true" spatial length that exists independent of any temporal consideration
  • The measurement just captures the spatial projection

But in special relativity, space and time are fundamentally intertwined. The "rotation" isn't tilting the object in space - it's mixing spatial and temporal coordinates. Length contraction isn't about measuring a spatial shadow of a rotated spatial object; it's about how spatial and temporal separations between events transform together.

Here's the key question: In your model, where does the "missing" length go? If the object has "true" length r but we only measure r cos(ψ), what accounts for the other r sin(ψ)?

In standard SR, the answer is clear: it's mixed into the time coordinate through the relativity of simultaneity. The two ends of the rod at "the same time" in the moving frame correspond to different times in the rest frame.

Are you proposing something different?

The time coordinate is dilated, which means it is smaller, too. The amount of the time dilation is very precisely measured, and there is no blending possible. Furthermore, this idea of blending only applies to Minkowski's perversion of Euclid. In eigenspace, the axes are always perpendicular, unlike Minkowski geometry. There is no blending of eigenvectors. Minkowski's geometry is just an isomorphism of Einstein's, and the rules of his geometry have no meaning outside of it. In eigenspace, the Pythagorean Identity remains valid. One of Minkowski's errors was that he assumed that the hypotenuse was the invariant, like in Euclidean geometry. To make this so, he had to redefine the formula for the hypotenuse. In reality, the invariant doesn't have to be the hypotenuse. In relativistic scenarios, the invariant is not the hypotenuse, itis the same vector as in Euclidean geometry, but it is the base of the triangle. Euclidean geometry and the Pythagorean Identity both work, because the base² = hypotenuse²-altitude². 

As to where the sine component goes, the short version is it goes into Elsewhere, not Minkowski's Elsewhere. His version is too restricted. But a vector pointed along a dimension in Elsewhere is invisible and unmeasurable. The idea of the light-cone is a waste of a good dimension. We already know that space is rotationally symmetric, we don't need that redundant information in the light-cone. I propose that since all relativistic effects can be aligned with a single axis, that we only need a flat spacetime plane to adequately describe relativistic effects on position. Each observer is associated with his own spacetime plane and vectors in it are real to the observer. However, since the Lorentz transformation is a rotation, and so is the polar tilt angle, two such hyperplanes that are not relatively stationary are tilted relative to each other. The dot product, which is commutative and symmetrical, determines how much of any vector in one frame projects onto the other. The magnitude of the projection is the cosine fraction, defined by the included angle, the tilt. Now, all such planes are embedded in a volume of Elsewhere. On any real plane, the Elsewhere coordinate is 0. But if a vector is tilted away from the real plane by relative velocity, it can be decomposed into the part parallel to the plane, the cosine fraction, and the rest, the sine fraction, which is perpendicular to the real plane, sticking out into Elsewhere. This model does not require faster than light velocity to reach into Elsewhere, but the part of the vector that does, vanishes. But to the co-moving observer, the vector is completely embedded in his reality, 100% real.

Dec 19

This is a highly creative and geometrically sophisticated alternative framework you've developed. Let me engage with it seriously, because there are some interesting ideas here, but also some fundamental issues.

What I appreciate about your model:

  1. You're correctly identifying that Lorentz transformations can be viewed as rotations with a rapidity parameter
  2. You recognize the hyperbolic nature (tanh, cosh, sinh relationships)
  3. You're trying to preserve Euclidean geometry and the standard Pythagorean theorem
  4. The symmetry of the dot product naturally gives you the reciprocal observations

But here are the critical problems:

1. Empirical predictions must match: Special relativity makes precise, tested predictions about things like:

  • The relativistic Doppler effect
  • Particle lifetimes in accelerators
  • The relationship between energy and momentum: E² = (pc)² + (mc²)²
  • Thomas precession
  • How velocities compose (not Galilean)

Does your "Elsewhere" model reproduce all of these? The Minkowski metric (-c²t² + x² + y² + z²) isn't arbitrary - it's what gives the correct physics.

2. The "eigenspace" claim: You mention eigenspace with perpendicular axes. Eigenspace of what operator? The Lorentz transformation matrices have complex eigenvalues (except for pure boosts in one direction). What physical meaning do these eigenvectors have?

3. Causality and light cones: You dismiss the light cone as "redundant," but it encodes causal structure - which events can influence which others. How does your model handle causality? If information is "in Elsewhere," can it violate causality?

4. The invariant: You say "the invariant is the base of the triangle." But which invariant? In SR, the spacetime interval s² = -c²Δt² + Δx² is what's invariant. All observers agree on it. What's the analogous invariant in your model that all observers agree on?

5. Observable vs unobservable: You say the sine component goes into "Elsewhere" and becomes "invisible and unmeasurable." But then how can we test whether your model is correct? If it makes the same predictions as SR for all measurable quantities, it's just a different mathematical formulation. If it makes different predictions, what are they?

Here's my central concern: It sounds like you're proposing that there's a "true" 4D or higher-dimensional Euclidean space, and what we call spacetime is just our 2D projection of it. The "missing" components are in orthogonal dimensions we can't access. But this faces the problem that SR isn't just about geometry - it's about the causal structure of reality and how physical laws (electromagnetism, mechanics) actually behave.

Can you address: What experimental prediction does your model make that differs from standard SR? Or is this a pure reinterpretation that gives identical predictions?

  1. I haven't examined all of these behaviors, but I can make some claims. Particle lifetimes are the result of the exact same rotation as length contraction. The dilated time is a consequence of rotating the time dimension into Elsewhere, just like the space dimension. The relation between energy and momentum can just as easily be derived using Euclidean geometry, perpendicular time and space projections and the Pythagorean Identity, contrary to all of Minkowski geometry. I haven't examined Thomas precession, because the rotational symmetry of spacetime allows us to reorient the coordinate system so that all frame velocity is parallel to a single axis. And how velocities compose is hyperbolic. By its nature, boost composition is by linear addition. Velocity is a transcendental function of a linear argument. Velocity composition can never by by linear addition. The only reason it appears to be in Newtonian physics is that ALL velocities in Newtonian physics are minuscule fractions of lightspeed. Velocity addition is a first-order approximation only. Boost addition is linear at all velocities.
  2. I haven't examined complex eigenvectors, because when you rotate the coordinate system, the eigenvalue is real, the k in Bondi's k-calculus is real.
Dec 19

You're making some bold claims here. Let me probe deeper, because I want to understand whether your model actually works or if there are hidden problems.

On your points:

1. E² = (pc)² + (mc²)²: You say this can be derived using Euclidean geometry with perpendicular time and space projections. I'd like to see that derivation, because in standard SR, this comes directly from the Minkowski metric. If you can derive it purely from Euclidean geometry with your "Elsewhere" framework, that would be significant. Can you sketch how that works?

2. Boost composition: You're absolutely right that rapidity (boost parameter) adds linearly: φ_total = φ₁ + φ₂. And velocities compose hyperbolically via v = c tanh(φ). This is standard SR. But here's my question: In your model, if boost is just a rotation angle into Elsewhere, and boosts add linearly, what happens geometrically when you compose two non-collinear boosts? In standard SR, you get Thomas precession - a spatial rotation emerges. Does your model predict this, or does the rotational symmetry you mention eliminate it?

3. Real eigenvalues: You mention Bondi's k-calculus. Yes, the Doppler factor k is real. But k isn't an eigenvalue of the Lorentz transformation matrix - it's a different parametrization entirely (relating received frequencies). The actual Lorentz boost matrix in the (t,x) subspace has eigenvalues e^±φ (where φ is rapidity), which are real. But for a general Lorentz transformation mixing all coordinates, you get complex eigenvalues. How does your eigenspace interpretation handle the general case?

Here's my core challenge:

You claim that length contraction and time dilation are both rotations into "Elsewhere," with the Euclidean Pythagorean theorem holding. So:

  • Contracted length: L' = L cos(ψ)
  • Dilated time: T' = T cos(ψ)
  • Missing components: L sin(ψ) and T sin(ψ) go into Elsewhere

If this is true, then L'² + [L sin(ψ)]² = L² and T'² + [T sin(ψ)]² = T².

But in standard SR, the spacetime interval is: (cΔt)² - Δx² = invariant.

In your model, what's the invariant quantity that all observers agree on? Is it just L (the proper length) and T (the proper time) separately? If so, how do you handle events that involve both space and time separations?

Can you give me the explicit formula for the invariant in your model?

  1. Let's examine the momenergy equation. As an aside, I would like to point out that  Energy is a scalar, and this is a quadratic equation. It is more appropriately a momentum equation, involving two perpendicular quantities. But energy and momentum are related by the invariant scalar, c, so this formula is equivalent to (E/c)² = p²+(mc)², where E/c is total spacetime momentum, p is total space momentum and (mc) is momentum in time, the residual momentum of an object with 0 space velocity, its rest mass times its velocity in time. How we get to this formula is simple.  Suppose we start with an abstract, stationary coordinate system of two perpendicular axes, and a unit circle at the origin. The invariant is the radius of the circle. Construct a tangent line at the tip of the radius. If the radius is rotated away from the axis, the tangent line will intersect the axis at some other point. While the radius is the hypotenuse of the right triangle inside the circle, it is the base of another right triangle outside the circle. The altitude of this larger, similar triangle is the tangent line, and the length of the hypotenuse of this triangle  is the secant of the angle of rotation. If we scale this drawing by the invariant, c, it becomes a velocity triangle. The base is velocity in time, c, the altitude is celerity in space, c tan(tilt) = βγc = u, celerity. Let's call the velocity in the direction of the hypotenuse, w = γc. This contradicts the Minkowski assertion that c is the fastest velocity in spacetime, regardless of velocity in space. On the other hand, measurements lie, and the cosine projection of this total velocity is always c, regardless of celerity in space, since γ cos(tilt) = 1. Now, scale the drawing again by the invariant, m. It now becomes a momentum graph. Around the larger triangle, the base becomes mc, the invariant of 4-momentum, the altitude becomes mu = m(γv) = γmv, relativistic momentum in space, and the hypotenuse is γmc = γmc²/c = E/c. The Pythagorean identity is (E/c)² = (γmv)²+(mc)² = p²+(mc)². If we scale this whole equation by c², we get the same equation you presented, but as I said, energy is a scalar and has its own linear equation, total energy = rest energy + kinetic energy, γmc² = mc²+(γ-1)mc². Coincidentally, rest energy is the invariant cosine projection of total energy, although kinetic energy is not the sine projection. 
  2. As far as the composition of different boosts is concerned, that's a little bit fuzzy. Because although even the standard approach gives the same magnitude, regardless of the order of applying the boosts, there are two different results for the direction, if there are 2 boosts, and 6 different results if there are 3 directions. The magnitude is well-defined, but the direction is not. This is especially troublesome if the composite direction is given and the question is what three boosts are combined. At this time, I can't say if it's right or wrong.
  3. Perhaps I implied too much about k. I used it as a shortcut to writing the exponential. It has nothing to do with frequencies. I question what is meant by the general Lorentz transformation, because there are 6 different permutations that all result in different general forms
  4. In any case, the fact that the composite of real and Elsewhere component is now an invariant has no effect on the spacetime interval. It is a relation between the real projections. The fact that the total length is an invariant for all observers too is extra. It has no analog in mainstream relativity, because the sine components are discarded. In other words, if every observer properly considers the effect of rotation induced by velocity, the individual length and time are invariant and equal to the measurement in the co-moving frame of the object, as well as the spacetime interval, which is only concerned with the real projections.
12:25 AM

This is a sophisticated framework you've developed. Let me engage carefully with each point.

1. The momentum/energy derivation:

Your geometric construction is elegant and does produce the correct formula. Starting with a unit circle, rotating by angle ψ (the tilt), and scaling:

  • Base (time component): c cos(ψ) = c/γ (in object's frame this is c)
  • Altitude (space component): c tan(ψ) = c sin(ψ)/cos(ψ) = γv
  • Hypotenuse: c sec(ψ) = γc

Then scaling by mass m gives you momentum components and (E/c)² = p² + (mc)².

This works geometrically. But here's my question: You say w = γc is the "total velocity in spacetime" and this contradicts Minkowski's assertion that c is the fastest velocity. But this isn't really a contradiction with SR - in standard SR, the magnitude of the 4-velocity is always c (in units where we measure it as √(-c²)). What you're calling w = γc is related but defined differently. The key issue is: what physical meaning does this "total velocity" have? Can anything be measured that goes faster than c in any observable way?

2. Boost composition:

You're right that non-collinear boost composition is tricky - the order matters for the resulting spatial orientation (Thomas precession). The magnitude is well-defined, but the direction depends on order. This is actually a feature of SR that's experimentally verified (in spin precession of particles, for instance).

If your model can't yet handle this, that's a significant gap. The Wigner rotation (Thomas precession) is a real, measured effect.

3. The invariant question:

This is crucial. You say: "the individual length and time are invariant and equal to the measurement in the co-moving frame."

So in your model:

  • Observer A measures a rod at rest: length L₀
  • Observer B moving at velocity v measures: length L₀ cos(ψ) in the "real" plane
  • But both agree the "total" length (including Elsewhere component) is L₀

Here's my fundamental problem with this:

If the "true" length L₀ is an invariant that all observers agree on, then you've reintroduced an absolute standard - the proper length. This makes the rest frame special again, which contradicts the principle of relativity. You're essentially saying: "Yes, the moving observer measures L₀ cos(ψ), but they're not measuring the real length - they're only measuring a projection."

But in standard SR, the contracted length is the real length in that frame. There's no hidden "true" length. The proper length is special only because it's the invariant spacetime interval, not because it's more "real."

Your response might be: "But all observers can calculate the 'true' length L₀ if they account for their velocity!" But calculate it relative to what? Relative to the object's rest frame. So you've made the rest frame privileged.

The spacetime interval:

You say the spacetime interval (Δs)² = c²(Δt)² - (Δx)² is "only concerned with the real projections." But in your model, if:

  • Δt' = Δt cos(ψ)
  • Δx' = Δx cos(ψ)

Then: c²(Δt')² - (Δx')² = cos²(ψ)[c²(Δt)² - (Δx)²]

This is NOT invariant - it changes by a factor of cos²(ψ). How do you resolve this?

Or are you saying that Δt and Δx themselves (including Elsewhere components) are invariant, so the "full" interval including Elsewhere is also invariant, but we only measure the projections?

Can you clarify: What is the explicit formula for the spacetime interval in your model, including all components?

The definitions I offer compare to the stipulations that distance difference is measured simultaneously and time difference is measured with coincidental clock locations. The two stipulations cannot be met simultaneously, because the two endpoints would be identical.

12:31 AM

Ah, now we're getting to something really fundamental about measurement in relativity!

You're pointing out that to measure spatial distance, we need to determine the locations of both endpoints simultaneously (in some frame), but to measure time difference, we need the clock to be co-located with the events being timed. These are indeed incompatible requirements when applied to the same pair of events.

This is actually the heart of why the spacetime interval is defined the way it is in SR - it's not that we measure space and time separately and then combine them. Rather, different types of separations (spacelike vs timelike) have different operational meanings:

Spacelike separated events: Δs² = Δx² - c²Δt² > 0

  • There exists a frame where they're simultaneous (Δt = 0)
  • In that frame, proper distance = √(Δx² - c²Δt²) can be measured with a single ruler

Timelike separated events: Δs² = c²Δt² - Δx² > 0

  • There exists a frame where they're co-located (Δx = 0)
  • In that frame, proper time = √(c²Δt² - Δx²)/c can be measured with a single clock

So are you saying that in your model:

  • The "true" (invariant) spatial separation and "true" (invariant) temporal separation exist independently
  • But we can't measure both simultaneously, so we only ever measure projections
  • The spacetime interval is derived from these projections, not from the underlying invariants

If so, how do you define "true" spatial separation when the events aren't simultaneous in any absolute sense? And "true" temporal separation when they aren't co-located in any absolute sense?

What determines which frame gives you the "true" measurements?

How does anybody measure any separation if the events are neither simultaneous nor coincident? This can't be done in relativity, either. All you can do is calculate the spacetime interval. Einstein stipulated that if you want to know one or the other components, then the measurement has to follow a protocol. What I'm saying is that the protocol of the measurement being a dot product of the length of the moving object with the reference in the stationary frame supersedes the individual specifications of simultaneity or coincidence of location, at any speed. The standard meter-stick is contracted by the same amount for both observers, As long as the "measurement" adheres to the protocol in the measurer's frame, both observers will get the same true measurement, and it will equal the measurement of the co-moving observer.

12:41 AM

Wait, I need to understand this more carefully. You're saying:

"As long as the 'measurement' adheres to the protocol in the measurer's frame, both observers will get the same true measurement, and it will equal the measurement of the co-moving observer."

This seems to contradict the fundamental result of SR. Let me work through a concrete example:

Scenario: A rod of proper length L₀ = 10 meters (measured in its rest frame).

Observer A: At rest relative to the rod. Measures length = 10 meters.

Observer B: Moving at v = 0.6c relative to the rod (so γ = 1.25, cos(ψ) = 0.8).

In standard SR:

  • Observer B measures the rod's length as 10/1.25 = 8 meters
  • Observer A measures Observer B's meter sticks as contracted to 0.8 meters each
  • This is symmetric and consistent

In your model, you seem to be saying:

  • Observer B should also measure 10 meters (the "true" length)?
  • But Observer B's meter stick is also contracted by cos(ψ) = 0.8 in Observer A's frame

If Observer B lays down their contracted meter sticks (which Observer A sees as 0.8m each) along the rod (which Observer A sees as 10m), Observer A would see it takes 10/0.8 = 12.5 of Observer B's meter sticks to span the rod.

But Observer B, using their own (to them) normal meter sticks, would count how many? You're saying they'd count 10?

That would mean Observer B counts 10 meter sticks, but Observer A watching this process counts 12.5 of those same meter sticks being used.

How can both observers count a different number of the same physical meter sticks being laid end-to-end?

Can you walk me through what each observer actually sees/counts in this scenario?

That's a misrepresentation. First, no observer can lay down measuring rods on a moving meter-stick. For relative motion other equivalent procedures, such as trigonometry must be used. Secondly, no observer can ever measure more than the cosine projection directly, anyway.  True length is the sum of the two components, which are perpendicular vectors. So in your example, the sine component would be 6 meters, if the cosine component is 8. We can't measure the invisible sine component, but we can measure the relative velocity, so we know that the invisible component is the tangent times the visible one. Each observer can only count 8 meter-sticks, even if they are both carrying what they know is a 10 m rod. How is that different from special relativity?

12:48 AM

Hold on - I think there's a fundamental confusion here, and I need to understand what you're actually claiming.

You say: "Each observer can only count 8 meter-sticks, even if they are both carrying what they know is a 10 m rod."

So in your model:

  • The rod's "true" length is 10m (invariant)
  • Observer B moving at 0.6c measures 8 meter-sticks
  • Observer B also knows the rod is "truly" 10m
  • The missing 6m is "in Elsewhere"

But this IS exactly what standard SR says! In standard SR:

  • The rod's proper length is 10m (invariant - all observers agree on this)
  • Observer B measures 8m (the contracted length in their frame)
  • Observer B can calculate that the rod's proper length is 10m using γ = 1.25

The proper length is an invariant in standard SR too. Everyone agrees what the proper length is; they just don't all measure it directly.

So where's the difference between your model and SR?

You mentioned earlier that "measurements lie" and that SR has contradictions. But if both theories predict:

  • Moving observer measures 8m
  • Both observers agree proper length is 10m
  • The 8m measurement is real and accurate in the observer's frame

Then what's the contradiction you're resolving? What does your "Elsewhere" model predict differently than standard SR?

Or is your claim purely interpretational - that SR is correct in its predictions but wrong in its interpretation that "length contraction is real" vs your interpretation that "length contraction is a projection effect"?

My model does not predict that the missing portion of the rod goes into the time dimension. we have very carefully measured time dilation, and there is no extra component associated with the missing 6 m projection. The Lorentz transformation says that the time dilation is the same fraction of the coordinate time as length contraction is of the Proper length. Any extraneous length component would interfere with this measurement.

12:53 AM

Ah, NOW I see a concrete difference you're claiming!

In standard SR with Minkowski spacetime, for a rod at rest in frame S with spatial length L₀ and temporal extent Δt:

When transformed to frame S' moving at velocity v, the "missing" spatial length IS accounted for through the relativity of simultaneity - it gets mixed into the time coordinate via the Lorentz transformation:

x' = γ(x - vt) t' = γ(t - vx/c²)

The cross-term (vx/c²) in the time transformation is precisely what encodes how spatial separation affects temporal coordination between frames.

You're saying: This mixing doesn't actually happen. The "missing 6m" goes into a third spatial dimension (Elsewhere), NOT into the time dimension. Time dilation is purely a rotation of the time axis into Elsewhere, independent of the spatial contraction.

So your claim is:

  • Spatial contraction: x' = x cos(ψ), with x sin(ψ) going to Elsewhere
  • Time dilation: t' = t cos(ψ), with t sin(ψ) going to Elsewhere
  • NO mixing between space and time coordinates

This would be empirically testable!

In standard SR, the relativity of simultaneity (the mixing term) predicts specific effects like:

  • The barn-pole paradox resolution
  • Desynchronization of clocks in the Hafele-Keating experiment
  • The specific form of stellar aberration

Does your model without space-time mixing reproduce these? Specifically, if two clocks are synchronized in frame S but separated by distance L, what does frame S' measure for their time difference?

In SR: Δt' = -γvL/c²

In your model: Δt' = ?

I've never been asked that specific question, so I don't have a ready answer. But I do think it matters how far S and S' are separated in distance as well as velocity.

1:01 AM

Wait - you said "how far S and S' are separated in distance" - but S and S' are frames (coordinate systems), not locations. They're separated by relative velocity, not distance.

Let me be more precise with the question:

Setup:

  • Frame S has two clocks at rest, separated by distance L along the x-axis
  • Both clocks are synchronized in frame S (they both read t = 0 simultaneously in S)
  • Frame S' moves at velocity v relative to frame S

Question: According to an observer in frame S', what is the time difference between the two clocks at a single moment in S'?

In standard SR, the answer is: Δt' = -γvL/c²

This is the relativity of simultaneity - events that are simultaneous in S are NOT simultaneous in S'. This comes directly from the cross-term in the Lorentz transformation: t' = γ(t - vx/c²).

In your model, you claim there's no mixing between space and time coordinates. So if both clocks read t = 0 in frame S, and time dilation is just t' = t cos(ψ), then both clocks should read t' = 0 in frame S' as well.

But this would contradict experiments! The relativity of simultaneity is experimentally verified.

Here's the critical test: Does your model predict relativity of simultaneity or not? If you eliminate the space-time mixing, you seem to eliminate this effect. But then your model makes different predictions than SR, and those predictions would be wrong.

Can you work out what your model predicts for this scenario?

But time dilation does require that the clock is located in the same location. If S' is moving, that is not possible.

1:03 AM

You're absolutely right that time dilation (comparing tick rates) requires following a single clock. But relativity of simultaneity is a different effect - it's about which events at different locations are considered simultaneous.

Let me separate these two effects:

Time Dilation: Compare one clock in S with one clock in S'. They tick at different rates. Both frames measure the other's clock as running slow by factor γ. This is symmetric.

Relativity of Simultaneity: Two spatially separated events that are simultaneous in frame S are NOT simultaneous in frame S'. This is about the synchronization of distant clocks, not their tick rates.

Here's a concrete operational procedure that doesn't require S' to be at the same location as both clocks:

  1. In frame S, place two clocks at x₁ = 0 and x₂ = L
  2. Synchronize them using Einstein synchronization (light signals)
  3. At the moment both clocks read t = 0, they each emit a light flash
  4. Observer in S' receives both flashes at different times
  5. S' can work backwards, accounting for light travel time, to determine: "At what times (in my frame) were those flashes emitted?"

Standard SR predicts: S' calculates the flashes were emitted at times differing by Δt' = γvL/c² (not simultaneous).

Your model predicts: If there's no space-time mixing (no vx/c² term), then... what? The flashes were simultaneous in S', just at different spatial locations?

This is experimentally testable and has been verified. Can your model reproduce this prediction?

By defining the two clocks to be at different, although fixed, locations, you intrinsically violate the condition for measuring time dilation. There are circumstance where the full Lorentz transformation must be employed. I would argue that this is one.

1:08 AM

I think we're talking past each other. Let me be very clear about what I'm asking:

I am NOT asking about time dilation. I agree that measuring time dilation requires a single clock.

I am asking about relativity of simultaneity - which is a completely separate phenomenon.

The question is simply:

Two events happen at different locations. They are simultaneous in frame S (both at t = 0). Are they simultaneous in frame S'?

Standard SR answer: No. They occur at different times in S', with Δt' = γvL/c². This comes from the Lorentz transformation.

Your model's answer: You said there's no mixing of space and time coordinates - only rotations into Elsewhere. So what does your model predict?


You say "this is a circumstance where the full Lorentz transformation must be employed." But the full Lorentz transformation INCLUDES the space-time mixing term:

t' = γ(t - vx/c²)

The -vx/c² term is precisely what creates relativity of simultaneity by mixing spatial position (x) into the time coordinate.

If your model doesn't have this mixing term (because space goes to Elsewhere, time goes to Elsewhere, but they don't mix), then you can't get relativity of simultaneity.

If your model does have this mixing term, then how is it different from standard Minkowski spacetime?

Which is it?

I'll have to think about this some more. But x/c is actually the time that it takes for light from one clock to reach the other. It is not a surprise that sine projections appear in more than 1 formula. The fact remains that if time and space are perpendicular then their cross-product in Elsewhere produces a resultant that is perpendicular to both. Maybe that's irrelevant. Maybe I overstated my case about Elsewhere. In any case, I don't care if it agrees with Minkowski. His model does get some things right. I think it matters that I can get the same results without giving up Pythagoras and Euclid.