What is "spacetime" really?

[Michael Mooney]

Modest, as above:

Situation A:

I'm on earth (motionless to the earth and sun) and I throw a baseball at the sun and the baseball is going 150,000 km/s relative to me (that's the speed at which I measure the ball) and it takes the ball one thousand seconds to reach the sun then what is my measurement for the distance to the sun?

 

Got it.Sun is 150 million Km away...takes the ball 1000 seconds to cover the actual distance.

 

Situation B:

I'm traveling at 150,000 km/s toward the sun and I throw a ball at the sun exactly when I pass the earth. The ball that I throw is going 150,000 km/s relative to me (that's the speed at which I measure the ball). It takes the ball 500 seconds to reach the sun. What is the distance from the earth to the sun as I measure it?

 

]Lightspeed: 299,792,458 metres per second,... say 300 million Km/s.

150,000Km/s (your speed toward sun) plus 150,000 Km/s (the *added* speed of you give the ball) gives the ball a velocity of 300,000 Km/s toward the sun. So it reaches the sun in 500 seconds.It is still 150 million Km away.

 

Now, beyond the "ball" to "something"... say photons traveling at lightspeed *which remains constant* regardless of the velocity of its source... which must remain sub-lightspeed....

 

Situation A.1:

I'm on earth and I throw *something* at the sun which is going 300,000 km/s relative to me. It takes this "something" 500 seconds to reach the sun. What is the distance from the earth to the sun as I just measured it?

Good grief, teacher (, we all know that lightspeed is constant, so whatever this "something" is, it is not light, because lightspeed is 300,000,000 Km/s and steady regardless of source, as above. The sun remains 150 million Km away regardless of your error of measurement.

 

Situation B.1:

I'm traveling at 150,000 km/s toward the sun and I throw something at the sun with a velocity of 300,000 km/s relative to me as I pass the earth. It takes this something 500 seconds to reach the sun. What is the distance from the earth to the sun as I just measured it?

 

Ditto my last sentence above.

Philosophically, specifically ontologically, the distance to the sun does not change with your error of measurement or your arbitrary statement that it takes 500 seconds to reach the sun. The cumulative velocity of you and that something (not light, as it has no cumulative velocity added to its source's velocity) is 450,000 Km/s. It will get to the sun exactly 1.5 times faster than the ball you launched in 'B.'...

That will be in 333.333 seconds. Your "500 seconds" was arbitrary, not actual.

 

Michael

[modest]

]Lightspeed: 299,792,458 metres per second,... say 300 million Km/s.

<...>

Good grief, teacher (, we all know that lightspeed is constant, so whatever this "something" is, it is not light, because lightspeed is 300,000,000 Km/s and steady regardless of source, as above. The sun remains 150 million Km away regardless of your error of measurement.

 

Light speed is approximately 300 million meters per second or 300,000 kilometers per second (not 300 million km/s). There are 1,000 meters in a kilometer. Can you please work out A.1 and B.1 again with this in mind. I just want to be sure we have a firm answer on all 4. Thank you for indulging me.

 

I'll respond to the other thing you brought up at the same time.

 

~modest

[Michael Mooney]

Modest was just doing his job as Moderator. The rules of this site require *every* member to back up their claims.

 

I admitted that I misunderstood his use of the exclamation point above, thinking it was a warning with the "badge of authority" to ban me. Sometimes I share "stuff" I read a long time ago and do not have handy reference links. I hope there is some slack in this requirement to allow sharing of knowledge, the exact source of which is not readily accessible (if it can be found on request.)

 

No members (Moderators included) are obligated to reply to your posts. We all have different reasons for replying to some threads, and not others. Reasons may include disinterest, lack of comprehension, lack of time, etc.

 

I did not assume any such "obligation." My use of the term "stonewalling" was an accurate description of moderators' refusal to reply, for whatever their reasons. I also did not know whether an "infraction" meant that moderators would , as a rule, not reply... and/or for what period of time. Modest cleared that up after I asked.

 

It's not that the subject matter is necessarily unworthy of examination/reply. I can't speak for everyone, but for me, I grew tired of the argument as well as the general tone of the thread.

 

I understand, and have change my "tone" as it was counterproductive to the spirit of honest scientific debate.

 

The ontological thrust of my thread "What is Enlightenment,Really?," though a philosophical question appropriate to the forum section, has never been addressed by a moderator. As Doctordick has pointed out, the epistemological assumptions of forum moderators seem to preclude actual discussion of what "spacetime" is, if anything beyond a metaphorical visual aid for illustrating the effects of gravity. Whether space is some "thing" that can bend, expand, etc., or no-thing is the still un-addressed inquiry. Likewise "time." That it is "what clocks measure" is not "science" as investigation of the "real world" but rather the philosophical error of tautology. The latter has never been addressed either. (Also appears as moderator stonewalling.)

 

Thanks for your "time."

 

Michael

[JMJones0424]

MM - I may be jumping the gun here, if so I apologize, but I believe your answer for question B is incorrect. I however, used a different formula than you did. I think Modest has nailed the problem.

 

I suggest you look at this link Relativistic Velocities

[modest]

MM - I may be jumping the gun here, if so I apologize, but I believe your answer for question B is incorrect....

 

I suggest you look at this link Relativistic Velocities

 

I would agree—according to special relativity we would expect a different answer for B. But, Michael is not yet sold on the relative nature of the universe. He is using Newtonian relativity and his answer to B is consistent (or correct) according to Newtonian relativity.

 

The thing I hope Michael sees is that Newtonian relativity is not consistent with a constant speed of light. His answer to B will be logically inconsistent with B.1. There will be a paradox between them that stems from using Newtonian relativity for B and Special relativity for B.1.

 

~modest

[Michael Mooney]

Correction: "What is Enlightenment. Really?" above should read "What is Spacetime, Really.?

(Had the magazine of that name ... sans "really".. stuck in my head. Sorry.)

 

PS: Pamela, thanks for the compliment. Not everyone is born into mystic gnosis...

... direct realization of the omnipresence of "cosmic consciousness" by whatever name.

 

Michael

[freeztar]

Stonewalling? I believe that term is inaccurate as several moderators have addressed your thread. But that not here, but there.

[Michael Mooney]

Modest,

Thanks for the correction. I clearly mis-spoke, rounding off exact lLightspeed: 299,792,458 meters per second,... to " say 300 million Km/s", which should have been meters per second, not kilometers per second.

I also mis-spoke in my last paragraph saying ..."The cumulative velocity of you and that something (not light, as it has no cumulative velocity added to its source's velocity) is 450,000 Km/s. It will get to the sun exactly 1.5 times faster than the ball you launched in 'B.'...

That will be in 333.333 seconds"

 

Nothing travels faster than light, and light travels sun to earth in 8.32 minutes or 499.2 seconds. So whatever the "something" was, it can not reach the sun in 333.33 seconds... a fact which I clearly overlooked.

 

I am not good at math, as I admitted right up front in my introductory statement to this forum community. You and JMJones0424 are undoubtedly correct that my math is wrong in the rest of my post above.

So please let me answer in plain English. I realize that SR is well documented for lightspeed remaining constant even when its source has whatever velocity, i.e., the source's velocity and light's velocity are not cumulative... for whatever very mysterious reason. My "take" on that is simply that light can not be "pushed" or pulled because it has no mass... nothing to push against. But I'm in over my depth on that too. (Yet somehow its *momentum* is such that it's trajectory can be curved/bent by massive bodies.

 

Now to the crux: There are three well known spacial dimensions and "elapsed time" for any event is commonly called the fourth dimension. The elapsed time for light traveling sun to earth is 8.32 minutes or 499.2 seconds... invariably. That is 149 million kilometers on average... give or take earth's out-of-round orbit. This distance, and the distances to the other planets does not change through some mysterious force of observation moving them closer or further apart. Because of the limits of lightspeed in conveying images, the distances may appear to change but they do not... but for orbit irregularities.

 

This is about subjective perception creating its own reality. It certainly makes what one person sees and when different from another as per relativity.

 

I want to thank you again, Modest, for the excellent article on the ontology of Euclidean vs non-Euclidean geometry and the consequent differences in cosmology. It also clearly stated the limits of math as not the creator of reality. So, though you can "out-math" me any day of the week, you still have not addressed the ontological question of "spacetime" which is the focus of this thread, or answered those specific questions I most recently asked.

 

I concede the challenge on the math. Please address the philosophical/ontological questions I have raised repeatedly... and the epistemology of the "facts and methods" shared most recently on the "well established distances" issue.

 

We do in fact *know* these distances to a very fine point of precision, and the way we know them, triangulation/parallax and sophisticated radar, infrared detection, etc., is also common knowledge. I remain mystified by your denial of all the above in the name of relativity. (It obviously has its place describing very accurately the differences in local perception, one point of view relative to another.)

 

BTW, I would appreciate it if you would spell out the math for me in the four situations you presented. I failed the math.

Michael

PS: Sorry to disappoint you and everyone on the math. One would assume that an ave. IQ of 174 would make short work of the simple math you gave me. But the nature of a "polymath" is excellence in several areas but with outstanding gaps in others.

[Pyrotex]

... even my basic challenge of the subjective idealism upon which the "axiom" "It is all relative" is based...

Gosh, Michael,

 

if you had just said you were making a Metaphor instead of a Theory, we would not have been so hard on you. Thanks for clearing up the misunderstanding.

 

Pyro

[JMJones0424]

MM-

Your math is not wrong, the equation you used for adding velocities was wrong. This is the central difference between Newtonian physics and special relativity. I doubt my ability to debate philosophically why this is, it is just that special relativity gives a more accurate prediction of the movement of bodies through space (3 dimensions) and time than Newtonian physics.

 

Through experiment, it can be shown that simply adding the velocities as you did in example B is incorrect, because velocity is distance traveled per unit of time, and time is relative to the observer's velocity. Evidence of this can be found in the paradox between your answers in B and B.1 . As long as you accept the speed of light as the universal speed limit, your original answer for B.1 is impossible. Either the formula you used must be incorrect, or the speed of light must not be the ultimate speed limit. It can be shown through experiment that the first of those two options is correct.

 

Solution for B:

 

[math]u = \frac{v_1 + v_2}{1 + \frac{(v_1 \times v_2)}{c^2}}[/math]

 

where u equals the velocity of the ball thrown relative to the sun, [math]v_1[/math] equals your velocity, and [math]v_2[/math] equals the velocity of the ball thrown as measured by you. C is the speed of light, but for simplicity's sake, we will use 300,000 km/s.

 

[math] u = \frac{150,000 + 150,000}{1 + \frac{(150,000 \times 150,000)}{300,000^2}}[/math]

 

[math]u = \frac{300,000}{1 + \frac {22,500,000,000}{90,000,000,000}}[/math]

 

[math]u = \frac{300,000}{1.25}[/math]

 

[math]u = 240,000 [/math]

 

And, 240,000 km/s times 500 s equals 120,000,000 km.

 

Solution for B.1:

[math] u = \frac{150,000 + 300,000}{1 + \frac{(150,000 \times 300,000)}{300,000^2}}[/math]

 

[math]u = \frac{450,000}{1 + \frac {150,000}{300,000}}[/math]

 

[math]u = \frac{450,000}{1.5}[/math]

 

[math]u = 300,000[/math]

 

And, 300,000 km/s times 500 s equals 150,000,000 km.

 

I agree with your assessment that the sun does not magically become 30,000,000 km closer in example B. Therefor, the problem is that the observer in B could not have possibly measure 500 seconds, proving that time is relative to velocity.

[modest]

I am not good at math, as I admitted right up front in my introductory statement to this forum community. You and JMJones0424 are undoubtedly correct that my math is wrong in the rest of my post above.

 

Your math was not wrong. Except for converting from meters to kilometers incorrectly, you did what you set out to do correctly. The problem occurred because your explanation (your physics / your concept) was internally inconsistent. You assert absolute space and time. According to absolute space and time (i.e. non-relativistic mechanics) the correct way to add velocities is simply to add them (that makes intuitive sense, after all ;)). When presented with this problem:

Situation B:

I'm traveling at 150,000 km/s toward the sun and I throw a ball at the sun exactly when I pass the earth. The ball that I throw is going 150,000 km/s relative to me (that's the speed at which I measure the ball). It takes the ball 500 seconds to reach the sun. What is the distance from the earth to the sun as I measure it?

You properly applied Newtonian (Galilean) relativity and added the velocities (150,000 km/s + 150,000 km/s) = 300,000 km/s. Multiply that by time (300,000 km/s x 500 s = 150,000,000 km) and you get 150 million kilometers. This is what you did here:

 

150,000Km/s (your speed toward sun) plus 150,000 Km/s (the *added* speed of you give the ball) gives the ball a velocity of 300,000 Km/s toward the sun. So it reaches the sun in 500 seconds. It is still 150 million Km away.

 

This is the correct answer according to your stated world view. As JMJones0424 shows, it most certainly is not correct according to special relativity, but, the first step (I think) is to show why your method doesn’t work. The answer to B.1:

Situation B.1:

I'm traveling at 150,000 km/s toward the sun and I throw something at the sun with a velocity of 300,000 km/s relative to me as I pass the earth. It takes this something 500 seconds to reach the sun. What is the distance from the earth to the sun as I just measured it?

As you correctly discern, this “something” is light (a photon—if you like). According to your stated belief: the speed of light does not depend on the velocity of the emitter and is always measured at 300,000 km/s regardless of the motion of observation. This light is then going 300,000 km/s relative to earth. We multiply by time as before (300,000 km/s x 500 s = 150,000,000 km). So, according to your proposed physics, this would make the sun 150 million kilometers away from earth as measured by the ship using light.

 

So, what’s the problem?... You’ve got a rocket passing earth going toward the sun which throws a ball at the sun and emits a photon at the sun—both at the same time. The person on the rocket launches the ball such that it’s going half the speed of the photon yet he concludes both will reach the sun in 500 seconds. This is a paradox. You can’t shoot two different things one going twice as fast as the other at a target and expect them to hit the target at the same time. Something is wrong with that explanation. It is not internally consistent—as well as being ruled out by observation.

 

The problem, then, is motion. If a ruler and a clock are moving relative to another ruler and clock and we demand that both ruler/clock systems measure the same velocity for the same photon then something has to give. What gives (according to special relativity) is our preconceived notion that distance and duration are universal. If you are moving relative to me then I cannot assume your clock will tick at the same rate as my clock. I cannot assume your ruler will measure the same distance as mine—even if these rulers and clocks are physically identical and subject to the exact same physical forces.

 

How this relates to the distance from the earth and sun...

 

Our person on earth (situation A and A.1) will measure a distance of 150,000,000 km between earth and sun. A clock on earth will measure 500 seconds for a photon to traverse this distance. As the person A (on earth) views B (the person on the rocket passing earth), B's clocks on the rocket will seem to run slow and B's ruler oriented in the earth/sun direction will appear short. This is how B *exists* according to A.

 

The same is true of B (the astronaut on the rocket). As he views the clocks on earth, they will appear to run slow. As he views the rulers on earth oriented in the sun/earth direction, they will appear shorter than his own. This is all a function of the relative velocity between the two. If B is going half the speed of light relative to A then he will find the sun/earth distance is 129,904,000 km. A clock on this rocket will measure 433 seconds for a photon to traverse this distance. The speed of light as measured by B is:

[math]c = \frac{129,904,000 \ km}{433 \ s} = 300,000 \ km/s[/math]

So, the speed of light is preserved. It is the same for all observers, but the amount of time it takes light to get from one object to another is not equal for all observers. Indeed, the distance between objects is not the same for all observers.

 

It's not just the speed of light that proves this. When special relativity is considered then we can derive the relativistic velocity addition formula and use it instead of the Newtonian velocity addition method you used for situation B. As JMJones0424 showed, the formula is:

[math]w = \frac{u+v}{1+(uv/c^2)}[/math]

The person on the rocket and the person on earth can both use this to figure how fast the ball is going relative to earth in situation B.

• B is going 150,000 km/s relative to A. u = 150,000 km/s
  
• The ball is going 150,000 km/s relative to B. v = 150,000 km/s
  
• The speed of light c = 300,000 km/s

The speed of the ball, relative to earth is then:

[math]w = \frac{150,000 + 150,000}{1+ \dfrac{150,000 \cdot 150,000}{300,000^2}}=240,000 \ km/s[/math]

240 thousand km/s. Since the earth is 150,000,000 km from the sun for the person on earth the ball will take (150,000,000 km / 240,000 km/s =) 625 seconds to travel the distance. This is different from the 500 seconds we would have expected using Newtonian relativity. This type of difference is tested by physicists all the time. Einstein velocity addition is the method that works.

 

The sun/earth distance for the astronaut is 129,904,000 km. How long, then, does the ball take to travel the distance as measured by B? (129,904,000 km / 240,000 km/s =) 541 seconds. This, again, is different from the 500 seconds we would have expected using Newtonian relativity and different also from the 625 seconds which A measured. With all this info, we can start to make some interesting comparisons:

 

While A measured 625 seconds, B measured 541 seconds.

and when using light to measure the distance:

While A measured 500 seconds, B measured 433 seconds.

 

According to special relativity clocks moving at half the speed of light will tick 1.158 times slower than the clock that is considered motionless. You can multiply the times measured by B above by 1.158 and see they do indeed equal the times measured by A. This is time dilation, and along with length contraction it has made our description of the universe consistent with a constant speed of light where it previously was not.

 

While this does not seem convenient and does not seem intuitive, it absolutely has been verified experimentally. Distance (as for example, between the earth and sun) is not absolute, but depends on the velocity from which it is considered. Distance and duration are relative to velocity. In a universe where things move relative to other things, space and time cannot be considered universal or absolute. Where you have said that the distance between the sun and the earth does not change with velocity—that is not a tenable position.

 

~modest

[Michael Mooney]

Gosh, Michael,

 

if you had just said you were making a Metaphor instead of a Theory, we would not have been so hard on you. Thanks for clearing up the misunderstanding.

 

Pyro

As Freeztar suggested, "But that not here, but there. " (Wrong thread for this.)

Most briefly: a metaphorical "fabric" does not actually bend, have shape, expand, etc. as science claims for "spacetime, hence my challenge of the ontological assumption of the existential reality of "spacetime."

Michael

 

Moderation note: this previous discussion was split from Does God exist as it is in context of this thread

[Michael Mooney]

JMJones,

First a quick reply to you before addressing Modest's post in depth:

You wrote:

Your math is not wrong, the equation you used for adding velocities was wrong. This is the central difference between Newtonian physics and special relativity. I doubt my ability to debate philosophically why this is, it is just that special relativity gives a more accurate prediction of the movement of bodies through space (3 dimensions) and time than Newtonian physics....

 

I agree with your assessment that the sun does not magically become 30,000,000 km closer in example B. Therefor, the problem is that the observer in B could not have possibly measure 500 seconds, proving that time is relative to velocity.

 

This thread addresses the ontology of what "spacetime" actually is, if indeed it is actually "something." This is a philosophical inquiry/debate.

I do not contest the fact that the equations central to Newtonian physics are outdated in light of the more accurate equations based on relativity. Yet this continues to be the thrust of all moderators' attempts here to correct my supposed misconceptions, specifically in this case the my contention that the actual distances between objects is independent of human errors in perception, which depend on light as a conveyance.

 

So, as you acknowledged, the distance between sun and earth does not actually change during the observations from different perspectives/velocities in the four situations at hand here, but rather the relative perception and its measurements change with relative velocities, etc. "Relative" to the actual distance between the bodies, which remains the same, this could be called "observer error" even while trajectory calculations are vastly more accurate using the improved math tools of relativity.

 

Thanks for your thoughtful and well articulated contribution.

 

Michael

[Michael Mooney]

Modest,

Up front, thanks for your indulgence, patience, and perseverance in "spelling it out" for me as I requested.

Please check my post to JMJones above for openers. I will reply to your detailed explanations below and will highlight your key phrases (key to my replies) in bold.

 

So, the speed of light is preserved. It is the same for all observers, but the amount of time it takes light to get from one object to another is not equal for all observers. Indeed, the distance between objects is not the same for all observers.

 

Without dispute, ..." the amount of time it takes light to get from one object to another is not equal for all observers."

 

So, the speed of light is preserved. It is the same for all observers, but the amount of time it takes light to get from one object to another is not equal for all observers. Indeed, the distance between objects is not the same for all observers.

 

Again, for all observers is the key, though it does not address the ontology of "actual distance" (if there is such a thing) as contrasted with "percieved distance", intrinsic to the phrase "for all observers."

 

It's not just the speed of light that proves this. When special relativity is considered then we can derive the relativistic velocity addition formula and use it instead of the Newtonian velocity addition method you used for situation B. As JMJones0424 showed, the formula is:

My challenge is no addressed to "relativistic velocity addition formula", which is an obvious improvement over Newtonian physics formulae, but with the *assumption* that actual distances change with differences in what is observable within the limits of lightspeed.

 

The person on the rocket and the person on earth can both use this to figure how fast the ball is going relative to earth in situation B.

 

Since the earth is 150,000,000 km from the sun for the person on earth the ball will take (150,000,000 km / 240,000 km/s =) 625 seconds to travel the distance. This is different from the 500 seconds we would have expected using Newtonian relativity. This type of difference is tested by physicists all the time. Einstein velocity addition is the method that works.

 

I understand and agree. But Earth is 150 million km from sun, period. The B-2 situation doesn't change this fact, just illustrates the relativity of perception and the velocities involved.

 

The sun/earth distance for the astronaut is 129,904,000 km. How long, then, does the ball take to travel the distance as measured by B? (129,904,000 km / 240,000 km/s =) 541 seconds. This, again, is different from the 500 seconds we would have expected using Newtonian relativity and different also from the 625 seconds which A measured. With all this info, we can start to make some interesting comparisons:

The perceived distance for the astronaut differs from the actual distance, which is not effected by anyones perception, velocity, or point of view. This is the difference between exalting relativity to the ultimate definition of reality and recognizing that celestial objects do not depend on human observation (or math) to define their actual positions in space relative to each other... i.e., the basic ontological question posed by this thread.

 

According to special relativity clocks moving at half the speed of light will tick 1.158 times slower than the clock that is considered motionless. You can multiply the times measured by B above by 1.158 and see they do indeed equal the times measured by A. This is time dilation, and along with length contraction it has made our description of the universe consistent with a constant speed of light where it previously was not.

This raises again the ontological question we have debated many times before. We agree that clocks, as above, tick at different rates. Why so?... is another question, highlighting the ontology of "time" which I have hammered to death in this thread. If time is not an actual thing (of any sort) then "it" does not "dilate." Rather, clocks keep time at different rates because of their differences in velocity (achieved by changes in inertia.)

 

Same ontological challenge applies to "length contraction." If space is emptiness (described by 3 dimensions, the line, as in distance, the plane, as in area, and volume, whether having geometric shape or in the larger sense of "infinite space") then "it" does not contract. Rather our instruments of measurement contract as forces effect them.

 

Relativity describes the "universe" of measurement of time and space in a way more sophisticated way than Newtonian physics. It does not, however, establish that relative perspective defines the actual distances and elapsed times as if the cosmos had no existence independent of such observations and measurement.

 

While this does not seem convenient and does not seem intuitive, it absolutely has been verified experimentally. Distance (as for example, between the earth and sun) is not absolute, but depends on the velocity from which it is considered. Distance and duration are relative to velocity. In a universe where things move relative to other things, space and time cannot be considered universal or absolute. Where you have said that the distance between the sun and the earth does not change with velocity—that is not a tenable position.

 

It may seem "convenient" to believe that humans and their observations and measurements in the relativistic paradigm define the ultimate nature of the reality of the universe, but I have consistently contended that this is not so, and the "objective cosmos" as I know it... through whatever unscientific means... can not be dismissed out of hand as disproven by the success of relativity in its own paradigm.

Space can remain that through which objects, of whatever speed and trajectory travel, independent of relative perspectives. Time can remain the elapsed time of any/all events independent of human-contrived units of measure or methods of measurement.

 

Finally to my basic challenge which you still have not addressed... here repeated in edited form:

Now to the crux: There are three well known spacial dimensions and "elapsed time" for any event is commonly called the fourth dimension. The elapsed time for light traveling sun to earth is 8.32 minutes or 499.2 seconds... invariably. That is 149 million kilometers on average... give or take earth's out-of-round orbit. This distance, and the distances to the other planets does not change through some mysterious force of observation moving them closer or further apart. Because of the limits of lightspeed in conveying images, the distances may appear to change but they do not... but for orbit irregularities.

 

This is about subjective perception creating its own reality. It certainly makes what one person sees and when different from another as per relativity

 

... So... you still have not addressed the ontological question of "spacetime" which is the focus of this thread, or answered those specific questions I most recently asked.

 

Thanks for your time. Please give some serioous attention to the ontology which is the focus of this thread as an inquiry into what might be objectively real independent of what can be observed from relative perspective.

 

Again, thanks.

Michael

[modest]

Your final quote in the last post has nothing moving relative to anything else. It has nothing to do with relativity. Obviously the people on earth will determine that the distance is about 149 million km. We just got done discussing that. You state as fact that such a distance is universal, objective, absolute, etc. But, you do nothing to support that view.

 

Can you follow my thinking when I say velocity is not universal and absolute? What, for example, is the velocity of Mars? There's no universal answer to that question. Velocity is only useful as a concept when it is compared to something else. Is this correct, do you follow?

 

If you disagree then let me know what the absolute and universal velocity of Mars is.

 

~modest

[JMJones0424]

MM- Please accept my apologies, as I seem to have provided support for views that are not correct. Let it be known, that if anything I say disagrees with anything modest says, than most likely I am wrong.

 

I agree with your assessment that the sun does not magically become 30,000,000 km closer in example B. Therefor, the problem is that the observer in B could not have possibly measure 500 seconds, proving that time is relative to velocity.

 

This statement was made in regards to B and B.1. Specifically, this statement was made using the same frame of reference of a velocity of 150,000 km/s relative to the sun that the observer in B and B.1 was experiencing. However, I used the frame of reference of the sun in the equations. I am still learning, and as my public high school education has left me woefully inadequate to continue in this discussion, I now bow out (hopefully gracefully).

 

Modest's link to Length Contraction was particularly helpful to me.

 

Please give some serioous attention to the ontology which is the focus of this thread as an inquiry into what might be objectively real independent of what can be observed from relative perspective.

 

Nothing is independent of what can be observed from relative perspective. There is no unique frame of reference. There is no objective reality except that all reality is subjective to perception.

[modest]

Oh, you're far too unassuming JMJones—I'm usually much-less correct then I sound :hihi:

 

Your opinion and contribution is most appreciated. Physics and philosophy aren't spectator sports, and we need all the players we can get in this thread :)

 

~modest