The idea that time is a 'fourth dimension' automatically (and maybe naively) begets the idea of 'time travel'. This is because treating 'time' as though some other mysterious 'direction' in space makes someone think of free movements through 'time' just like we freely move 'through' space. In fact, if time is a fourth dimension, it becomes more difficult to understand why time travel does not happen than how it can happen, at least not, why time travel does not as easily happen as any other travel through space. Since theoretical physicists are the ones talking of 'time' as a 'fourth dimension', it is natural to wonder if this physics at least gives some platform for the possibility of 'time travel'. Here, I am going to show you that absolutely, this is not the case!

To understand this, begine by noting that the idea that time is a 'fourth dimension' was not observed in nature. In fact, they cannot even imagine how such a monster as 'four dimensional space time' can be! This should ring alarms as science should be about observations. But by the time of relativity and quantum mechanics, science had been redefined as 'what scientists do'! Observation was no longer a necessity. We 'discover' by looking at an equation, not by standing somewhere in nature and using your eyes! Such is how 'fourth dimension' was 'discovered'. Indeed such is the only way one can 'discover' something that he himself admit that he doesn't know nor even imagine where it is! Imagine if Farraday told you that he can't even imagine where the wires, magnets, dynamos, motors and transformers are. What would it become of 'discoveries' of electromagnetic induction etc? Have this one in mind as we close examine what 'fourth dimension' might say about 'time travel'.

One might (perhaps naively) think that by talking of 'time' as 'fourth dimension', physicists think that 'passage of time' is the literal motion along the 'fourth dimension'. So if you move into the fourth dimension 'faster than the things around you', then you will automatically move into their future. But in 'time travel', such 'motion to the future' makes something instantly disappear. So it is like there are endless layers of 'universes' each lagging behind another in history. But this cannot be what the physicists imply as can be seen when they try to use such 'motion into the future' to, instead, explain 'time dilation' and other relativistic transforms.

To explain lorentz transforms using the Minkowski Spacetime (where time is treated as a 'fourth dimension'), the space axis (x axis in a Cartesian Plane) is tilted into the 'fourth dimension', i.e. towards the 'time' axis. This means that the points along the x axis that are further away from the origin (the (0,0) point in the Cartesian Plane) are already 'into the future'! But then we can still see this locations at the 'present'! So the supposed 'time travel' that the Minkowsky Spacetime suggests in fact doesn't literally take anyone 'out of the present universe'. It is not a 'time travel' in any literal sense we understand 'time travel'. So 'traveling along a fourth dimension faster than the things around you' does not result in you 'time traveling' into the 'future'. It just means that your clock now tick faster than the surrounding clocks. It is just a 'time dilation'. A clock that has 'ticked faster than the others' does not, in relativity, goes to the future. It is still ' at the present moment', only indicating the 'present' as though it were 'the future'. Or in short, the 'time dilation' of relativity is SUBJECTIVE. It is the 'opinion of the clocks'. If one indicates Wednesday while the other is indicating Tuesday, then one 'is in the future of the other' in the sense of 'Minkowski Diagram', hence the need to depict 'time' as though the same thing as 'space', with the ability of one person 'rotating into it'. So 'fourth dimension' is actually pointless!! It is pure poetry! The two clocks that disagrees on whether it is Tuesday or it is Wednesday are both indicating THE SAME TIME. It is not that one of them is literally 'into the future' of the other. So we can take them to the museum, or throw them to the dustbin!

Even that being the case, taking Lorent's Transforms as 'rotations' in some four dimensional spacetime is still problematic, as I will next show. Like I hinted at the beginning, just gawking at an equation cannot tell us anything about what it might be describing in the real world. In this case, we specifically cannot infere that we are describing a 'four dimensional' scenario just because we are relating four parameters with Pythagoras-like relationships and things like 'angles' between them. If, for instance, you place one right angled triangle call it triangle A, on another such triangle, call it B, so that the base of A sits on the hypotenuse of B and A's base length is equal B's hypotenuse length then A's hypotenuse,d, will be given by d^2=a^2+b^2+c^2, where a is the base length of B, b is the base length of B and c is the height length of A. That is we have one hypotenuse, becoming the base of another triangle. Thus an equation cannot tell us how things are arranged or oriented in space, as A could be oriented at any angle relative to B. These are matters of observation of the world. Equations can only relate sizes of things, but never can they tell us what those things are or even remotely hint to us how they look like or how they are arranged in the real world.

In the case of Minkowski Space time, it is even worse because the equations still donnot make any geometrical sense even when we agree that lorentz transforms are indeed describing a four dimensional scenario. Relativists are miles away from reality! The equations look like those of 'geometry' merely in the manner of how symbols sits next to each other. It is a purely aesthetic similarity! The so called 'space-time' interval is supposed to be the 'hypotenuse' in the four dimensional 'space', but it is actually shorter than the base! It is given by

s^2=x^2+y^2+z^3-c^2t^2. So a 'minus' sign always sits to the left of 'ct' (or equivalently, . This is NOT a Pythagorean relationship! Infact if we were to force it into a Pythagorean Relationship, then the 'time' axis will be imaginary in the sense that we must always multiply it by a squaroot of negative 1!

But the 'space-time' interval, s, has many interpretations within a 3 dimensional space. If you shoot light to the roof of a moving train, say at distance x away from you, then the height of the train, h, will be given by: h^2=c^2t^2-x^2. So h can perfectly be interprated as the 'space-time' interval. Since the height of the train does not undergo any relativistic transformation, we understand why h is invariant in all frames of references. The Minkowski's 4 dimensional interpretation is obviously Ptolemaic with respect to this straight foward interpratation! Perharps Minkowski could not understand why the equations yielded an invariant spacetime. Perhaps he thought this was a very deep mystery. So he only thought of roating a rigid stick if a four dimensional space! Even with that, as we saw, it still cannot explain it at all because we have imaginary time axis which makes no sense in the real world!

We can deduce Lorent's Transforms this way: A right angled triangle is sitted so that its base lies horizontally and its height lies perpendicularly. Let PQR be its vertices. It is sitted so that P is at the left most part and R is at the top most part. So R lies directly above Q, PQ is its base lenght, QR, its height length and PR its hypothenuse length. So of the three angles of the triangle, PQR, the angle P will be at the opposite to the height QR. This will be the angle at vertex P. We now have PQ=PRcosP and QR=PRsinP. Suppose you now tilt the triangle upwards about vertex P by some angle B. So vertex P remains on the spot, but both vertex Q and R are taken upwards. Dropping a perpendicular from R to the horizontal plane nologer meets the plane at Q, but at a point nearer to P, call it Q'. It is now the length PQ that transforms to PQ' in a 'Lorentz Transform'.

Then PQ' will be given by:

 As you can see, to regard the Lorentz Transform as to be due to a literal tilting into the 'fourth dimension', we must replace a geometric distance, PR with'ict', rather than ct. The factor 'i' spoils the idea that time is a space-like 'forth dimension' one can somehow 'travel through'. In fact it makes the whole idea senseless! So Lorentz transform as a geometric rotation in a four dimensional scenario cannot make sense even to an alleged 4 dimensional creature. It is a total nonsense for a relativist to say that it is us being 3 d creatures that makes us difficult to understand such an idea. Rather, it is its inherent irrationality that makes it ununderstandable!

As I have suggested in some blog posts, we ,in sensible physics, never need to understand the equation v=ccosθ as to imply that c is the hypotenuse length of some right angled triangle, and v is its base length. The equation occurs in cases where geometry of triangles are not occuring at all. One such example is in sinusoidal waves, where c is the amplitude of the wave. It is even worse in longitudinal waves described by the same v=ccosθ. There is absolutely no geometric similarity with a right angled triangle. But they are described by the same equation!

If a force, F, acts on an object, but at an angle,θ from the horizontal, the component of that force that acts horizontally will be Fcosθ, and the component of that force that acts vertically will be Fsinθ .If the object is constrained to move only horizontally, then it is not unusual for the object to move at speed v=ccosθ, where c is its speed when the force acts directly on it, which is its maximum speed. This is because when there is friction, the force exerted on an object is proportional to the speed it will gain. The key point you should note is that we can think of an object moving at c at the angle θ, and to the horizontal and still describe the movement of its shadow as to be v=ccosθ. So we must be careful when interpreting such equations as the same equations can describe two totaly different physical things. It is this way that I explained the relativistic effects, like in this:

On the other hand, it is obvious that the 'geometric' interpretation of Lorentz's Transforms as though to be due to 'tiltings' in a four dimensional spacetime takes the shortening of objects due to 'length contraction' in the same way the shadows 'shortens' or 'lengthens' depend on the angle of sun shine! This is ridiculous because they haven't told us by what mechanisms we can be seeng the 'shadows' of objects tilted into the 'fourth dimension'. Same is the case for what the hell of a mechanism tilits the whole of space by mere motion of an object? Obviously, the 4 dimensional concoction was done by people not interested in gaining the actual insight as to what causes relativistic effects. They were merely interested in mathematical aesthetics!