Would phenomenology explain a feature of Enstein which relates to gravity? That is, if you jump on a moving train, why does the train not pass below your suspended feet? Can you explain this by a mathematical calculation involving gravity acting vertically, as well as horizontally of which effectively it is calculated 0? Because no velocity is involved how can you explain this phenomenon? Please elaborate.

I would be very interested in your answer. I personally wouldn't know how to answer your question (s).

I do not think there is much to explain when you and the train have the same speed. If the train breaks while your are up you would land in a different place in the train. Horizontal gravity is to small or balances well to be noticeable.

At these speed and time scales Newtonian physics is sufficient for explaining the phenonena. As you are standing (or riding) on the train, the floor (or seat) of the train exerts a horizontal force on your body, accelerating you until you are moving with the same horizontal velocity as the train. At this point you and the train have identical horizontal velocities. When you jump (straight upwards) you apply a downward force to the floor and it, in accordance with the third law, applies a force upwards unto you, sending you upwards. While you are in flight the only force acting on you is gravity; that is, you will only experience acceleration in the vertical direction. Since you have no horizontal acceleration, your velocity in the horizontal direction remains constant and you keep up with the train. 

Andrew,With train as a frame of reference the question can be 'answered' as the scale is minuscule. Even if there is a displacement and you land millionth of an inch behind, it is insignificant from a practical point of view, however in a larger scale the question remains troublesome. Here is a question I have been placing before physicists who routinely answer like you did and I still remain unconvinced. 

Should we need to travel lets say from New York to Tokyo, all you have to do is take a helicopter and go high above the ground and wait till Tokyo come below you and you land! At most the Helicopter will be subject to the momentum delivered to it by the earth's rotation, but the momentum will ease at some point. I am not sure the answers I have seen elsewhere are satisfactory. 
George

Hi,

According to General Relativity, gravity is the curvature of space-time by the mass-energy contained in that space-time.  The mass-energy of the speeding train would curve space-time and the mass-energy of you would curve space-time as established by the Einstein Field Equations.  In this case, your curvature of space-time would intersect the curvature of space-time of the moving train.  At this point the space-time interval between the two events (you and the speeding train) would have a space-time interval of 0 (the null space-time interval).  The space-time interval between you jumping and the speeding train would gradually diminish until it reached 0.  The null space-time interval indicates that the two events (you jumping, speeding train) are at the same point in space-time (you and the speeding train are at the same place at the same time).  Since space-time intervals determine the organization of conscious experience (shown is some of my publications), the conscious experience (phenomenology) of you jumping on a speeding train is fulfilled. 

Dear George,This is a partial answer to your last scenario. 

In the simplified case if there is no atmosphere (which excludes helicopters hoovering) the gravitational force can be balanced by a propulsion engine with the help of an idealised perfect control system such that the net force acting on the vehicle is zero. 

The initial tangential velocity due to motion of the sphere surface imparted on the vehicle will continue due to inertia in a fixed direction from the moment no net force acts on the vehicle.

 As a result, constant velocity in the fixed direction will drive the vehicle away from the sphere into the outer space to infinity. This is the same effect as for the stone released from David's sling that killed Goliath.

In the real case, the effect of atmosphere cannot be simply deduced without taking account all forces resulting from its presence due to gravity. This is beyond a simple logical answer.

My brother a lawyer now in the UK, I think he is quite the genius to think it up when we were travelling on a train together, he was 13 and I, 14. I like an outrageous answer when it comes to philosophy rather than a wrong one like accepting Mill's utalitarianism to be totally hedonistic yet possibly hold  some practical truth. Sometimes philosophy diminishes in it's search for an answer. I am not a genius mathematically or a  physicist nor as talented as my brother. Maybe someone knows some quantam physics? Perhaps a close look at the nature of reality and transcendent states is more explicable. Then there remains knowledge which would be greatly appreciated from people who can leviate or far eastern yogis to explain this phenomenon. I can only be general here until I have done an appropriate study and it is fresh in my mind.

Apparently nobody dares tackle my original query concerning Stevin and Einstein. No harm done. Since there are people here much more knowledgeable than me in Physics, and I have still much to learn, then I hope that someone will explain to me something that has also been puzzling me.
Space contraction, according to Lorentz and Einstein, finds place only in the direction of motion, say, the x-axis. The y and z-axes remain unchanged.
I find it impossible to picture. It seems to me that a figure whose x coordinates are changed will have also different y and z coordinates, and will therefore have a different shape altogether.
Let us take a 3D cone and consider it as a 2D triangle for simplicity. Changing the base will necessarily change the hypotenuse. In a cone that would mean that the base could go from a perfect circle (which by the way do not exist:  http://philpapers.org/post/17434 ) to an ellipse. Or do I see it wrong?

Constancy of the speed of light:
If we accept the fact that c has the same value for a stationary and a uniformly moving observer, and further accept the idea of space contraction and time dilation, then we must conclude that the speed of light in one case is different from the other.
Let us say the stationary observer notes that distance/time=c. The units used are fundamental for the quantitative evaluation of the expression. You cannot decide that  x kilometers/ y kilometers = c miles.
Still, that is exactly what Einstein seems to be doing when comparing the speed of light in both cases.
After all, measuring rods and time intervals are diminished by a factor gamma. Which means that for a neutral observer, who of course cannot exist in Relativity, 1 meter on Earth is more than 1 meter on a starship moving at high velocity. The same for the time interval, one second on Earth will be longer than one second on the ship. Still, Einstein claims that c is the same in both situations.
Any comment?

Dear Hachem,The contraction can only apply to moving object 
Each moving object remains the same length as it was in previous rest. Take the object made of three meter sticks laid one after another. They remain three meter sticks no matter how fast yhey fly. Space does not contract but the objects may. The body at rest may see a circle flattened along its x axis but not y axis if the net velocity is exactly along the x. It is not like pressing a baloon which would grow in y axis while shrinking in x.
When it comes to speed of light it appears that the average round trip speed on any system as measured by a single clock is the same. Einstein makes a postulate that one way speed of light is the same in any system. Acording to this assumption he describes how to syncronise two clock to achieve this effect. He claims this synchronisation represents simultaneous synchronisation without any proof. The definition of simultaneity was unknown to him so he made this one up. Einstein's pseudo-simultaneity can be practically realised and legitimately used in physics in a similar way flat maps are useful in geography off the ellipsoidal globe. Poor understanding of Einstein's pseudo-simultaneity leads to known paradoxes.
You may stretch the map near the North pole so the one by one degree area looks like a square but you cannot claim that all distances between adjacent corners of such square sre the same as the map distorts the reality while representing it one to one.
You will not find this explanation in books...

I was hoping to get more than a summary of what Einstein says and claims. You say:" It is not like pressing a balloon which would grow in y axis while shrinking in x." I am curious about what you think about such an assertion. It seems to mean that rules that apply to objects on earth do not apply to those moving very fast. So, what kind of world is it really? The x-axis rule seems to be completely arbitrary, only there because Lorentz and Einstein were interested in only one dimension, the direction of light rays. And maybe because it made calculations much easier.
I am afraid that I lack imagination in this regard. A balloon that gets squeezed in one direction pops out in another. And that goes also for an iron ball.

Concerning the speed of light.
Again, I know what Einstein claims and what we are supposed to believe. Fact remains that for traveling souls measuring rods are shorter and clocks are slower. Shorter and slower than what but earth rods and clocks? Which means that  the speed of light as measured on a starship either gives as a result 300.000 shortened kilometers a slowed second, or, to be equivalent to our 300.000 km/s, the traveler should measure a much higher number. In which  case his conclusion would be that the speed of light is, say, 400.000 km/s.
Either way, the speed of light as measured by travelers is different from that measured by earth-bounds.You can of course always say that the 400.000 are in fact the same as the 300.000. But the same in what way? And who would be allowed to say that?

This makes me also very curious about the validity of the experiments that are supposed to confirm Relativity Theory. Which version of light speed are they using each time? And is it the same in the whole experiment, or do they, unconsciously or not, regard them both as identical and therefore do not distinguish between them? I am trying to look in this issue but I have to admit that my non-scientific background might be a hindrance. I am therefore very interested in what other people, physicists, have to say on this.

By the way, I have downloaded your articles and hope to read them soon.

Hi Hachem,

Einstein's special theory of relativity is based on two postulates: (1) the laws of physics are invariant (the same) for all inertial (constant velocity) frames of reference, and (2) the speed of light is the same for all observers, regardless of their motion.  In order for (1) and (2) to be valid for reference frames (observers) travelling at different speeds, time must dilate (slow) and space must contract (shorten).  Space in this sense refers to three dimensional space.  Space may shorten along the x, y, and z coordinates or all three coordinates (indicated by a displacement vector r).  Special relativity has been shown to be valid experimentally in all cases.  The thing to remember is that time must dilate and space must shorten to keep the laws of physics and the speed of light the same for all inertial frames of reference.  Special relativity does not consider gravity.  This is made more general in general relativity which deals with gravity-the curvature of space-time by the contained mass-energy.  Another interesting thing that arises from relativity is the space-time interval.  A space-time interval is the separation between two events in four-dimensional space-time.  An event in space-time has four coordinates (x, y, z, t).  A space-time interval represents the separation of two events in space and time.  In order to keep the laws of physics and the speed of light the same for all observers, space-time intervals must be the same for all observers.  This invariance of space-time intervals occurs because of the time dilation and space contraction that occurs.  Space-time intervals appear to determine how you observe things (your observed physical reality, your conscious experience).  An interesting observation is that Einstein developed his special theory from his own consciousness.  What he actually described was the organization of conscious experience (our observed physical reality). 

I am afraid I have to say the same thing again. You have summarized very nicely what Einstein says and claims. You refer to the experimental confirmations as speaking for themselves. The only new thing is your theory of 4D consciousness. The latter is I'm afraid beyond my grasp.

Dear RichardIt is a short and good summary of relativity theory except that the spacetime is an abstraction which differs from tangible space and perceived time in a similar way as the flat map differs from the real terrain. Both exist in their own right but they are two different things. The coordinates representing space only exist as a record of measurements based on rigid bodies or they can be marked by a grid on a material structure. 
Space does not contract because the space that would contract would have to move and this is an absurd. How many moving spaces do we have? As many as moving particles or more? If a particle moves from rest, does its space moves instantly ad infinitum or slowly at the speed of light?
Real space does not move or contract due to speed but  objects might. Object also expand if reverted to the original rest, and no one talks about it because it destroys the legend of naive reciprocity. 

Time is only a set of indications of synchronised clocks using physical phenomena. There is no sensible definition of time in physics other than that given by Einstein:
The local times of all space points taken together are the "time" which belongs to the selected system of inertia, if a means is given to "set" these clocks relative to each other. One sees that a priori it is not at all necessary that the "times" thus defined in different inertial systems agree with one another.

That one is is from 1949.

Hi Hachem,

When you were writing about space contraction, you were thinking in three dimensions.  Einstein talks about the situation in four dimensions (space-time).  In Einstein's space-time, the motion occurs in four dimensions (through space and time).  Space contraction is balanced by time dilation maintaining the relationships between the events observed.  Einstein also said that there is no stationary observer.  All observers are in motion. 

1) I tend to agree with Andrew Wutke that contraction concerns objects and not space itself. But the difference of interpretation between both of you is very interesting. It would be worth investigating it further. Besides, the idea that space itself can change shape is at the basis of General Relativity.
2) Granted, the idea of spacetime  has offered an original way of presenting events in something else than the perennial Cartesian coordinates. As far as I am concerned, it is its only use. It is philosophically and metaphysically a stillborn.
3) I know what Einstein says over  a neutral, or stationary observer, but his whole theory stands in stark contrast to his verbal claim. Without the perspective of a stationary observer he takes in all his analyses, he would not be able to say a single thing about what happens elsewhere but in his own frame of reference: Earth. In other words, his theory, without a stationary observer able to watch what is happening in a ship moving almost at the speed of light, wouldn't make any sense at all. Not that it does anyway.

This is an interesting question.  I agree that if you just look at Einstein's special theory of relativity, it appears as just a four-dimensional coordinate system convenient for understanding observed physical reality.  However, all predictions of this theory, including space contraction, have been validated experimentally.  I have found a great deal of empirical research indicating that there is a neural correlate for human conscious experience found in the human brain that is precisely modeled by Einstein's special theory of relativity.  Einstein's special theory is not just an artificial coordinate system used to describe observed physical reality.  It appears like the human brain actually utilizes this system to organize human conscious experience.  It is as if the human brain used the special theory of relativity as a blueprint for the organization of our conscious experiences.  It is more probable that Einstein used his own conscious experiences (he was fond of thought experiments) to develop his special theory (and general theory).  At any rate, the special theory is not just a convenient coordinate system, but is the way the brain actually composes conscious experiences.  Our conscious experience is our observed physical reality.  We observe (experience) objects as conscious experience.  I have found that human conscious experience is built from three core types of information: what, when, where.  What is the objects and events making up the conscious experience.  Where (space) and when (time) form a context for the what, i.e. the circumstances which form the setting by which the what can be assessed and understood.  Hence it appears like contraction is of space itself and not specifically of objects (although objects contain a great deal of space).  The way we observe (experience) objects is determined by their relative position in space (where) and time (when).  Space contraction is a natural consequence of the neural system itself.  These ideas are all based on empirical data and not just on my speculation.  

I beg to differ. See my thread Quantum Computing: Myth or Reality? especially the posts concerning Relativity. For the so-called empirical confirmation of space contraction, maybe my arguments in  http://philpapers.org/post/18962 will convince you. 

Who has ever proven space contraction? Theoretically let alone experimentally.Under certain conditions it has been likely proven experimentally that the evolution of objects slows down when they move relatively to some rest frame of reference. If the Special Relativity is correct, the length of such objects in the direction direction of motion must contract relatively to the same rest frame. Space is common to all and it cannot contract because one object decides to move. This is strictly in relation to SR

Interesting. What then makes space common to all and time relative? I think the idea of spacetime is pure nonsense, metaphysically speaking, but how would you justify GR if you deny space relativity to it? And since SR is supposed to be just a special case of GR, concerning only uniform motion, how can space contraction be valid in one case and not in the other?All very important themes, but  I don't think metaphysical arguments can win the day. The strength of Relativity Theory lies in its explaining and predicting power. The only way to dislodge it from its pedestal is to offer explanations and predictions that are at least that good, and which do not make use of the metaphysical assumptions Relativity carries around.
This is a time where the level of my mathematical and scientific knowledge really proves to be a handicap. I can only hope that my "non-scientific" objections will encourage people more knowledgeable than me to look critically at the theory.
What I have read of critics of this theory is I'm afraid not very encouraging. They are all seem keen on proving that somehow Einstein's calculations or mathematical assumptions were wrong. If that had been the case, I think that mathematicians would already have discovered it. As Sean Carroll said, anyone would jump on the opportunity of proving Einstein wrong. It would be be the start of a beautiful career.
I personally think that the only viable approach is to build an alternative theory and not worry about the consistency of the Einsteinian approach. I can of course do nothing else but that since I miss the expertise to build such a physical theory. My metaphysical skirmishes have only one goal, to show that Relativity Theory is metaphysically inconsistent, and that we therefore need an alternative.
Therefore, even if I am successful, somebody will have to build that alternative physical theory. 
One thing is certain. It won't be me.

You cannot have time dilation without space contraction since both are based on the idea that moving clocks are slower than stationary ones.
 http://philpapers.org/post/19246

I think you mentioned Bergson in one of your articles, well, that is exactly what he was fighting against!