What is "spacetime" really?

[modest]

I am familiar with Galilean/Newtonian relativity...

 

The Lorentze transformation *assumes* time dilation and space curvature, both of which are clearly cases of erroneous reification, as I have meticulously argued in this thead.

 

The only thing the Lorentz transformations assume is the invariance of the speed of light.

 

Derivation of the Lorentz transformations

 

You conveniently ignore all my arguments in this regard and glibly state that Galilean/Newtonian relativity" has been proven wrong"... without specifics to back up the claim.

 

If Galilean relativity worked (or correctly described our universe), GPS satellites would not work correctly. Planes would most-likely crash into mountains killing people.

 

GPS and Relativity

 

Your problem is claiming that Newton’s law of gravity and Newtonian relativity give the right answers as you do here:

 

Gravitation is a field which acts as per the universal law thereof, "directly with massiveness and inversely with distance"... Just like Newton said. He didn't like "action at a distance" either, but the equations still work, as all astronomers and "rocket scientists" know.

 

Until you can get past these basic misconceptions, your conclusions are going to continue to disagree with reality.

 

Time dilation is proportional to relative velocity, not acceleration. So, time dilation cannot be an effect of inertial forces

Prove it. "Time" is not "real."

That time dilation depends on velocity rather than acceleration is proved by Bailey et al., “Measurements of relativistic time dilation for positive and negative muons in a circular orbit,” Nature 268 (July 28, 1977) pg 301.

The experiment of Bailey et al. referenced above stored muons in a magnetic storage ring and measured their lifetime. While being stored in the ring they were subject to a proper acceleration of approximately 10^18 g (1 g = 9.8 m/s^2). The observed agreement between the lifetime of the stored muons with that of muons with the same energy moving inertially confirms the clock hypothesis for accelerations of that magnitude.

 

* Sherwin, “Some Recent Experimental Tests of the 'Clock Paradox'”, Phys. Rev. 129 no. 1 (1960), pg 17.

 

He discusses some Mössbauer experiments that show that the rate of a clock is independent of acceleration (~10^16 g) and depends only upon velocity.

 

Experimental Basis of Special Relativity

Time dilation is shown not to be an effect of acceleration or inertial forces. It is also shown to be a real effect— regardless of how real or not-real one wishes to consider time.

Of course you are consistently referring to "time dilation" as a given... long ago "proven" and no longer deserving of thoughtful consideration.

The actual difference in forces upon the speeding clock and the control clock, in all cases, is that the former has been "forced" to speed up and slow down, both changes in inertia. I suspect that human metabolism also slows down under exposure to the forces of acceleration /deceleration.

A freefalling observer (such as a clock in orbit) feels no acceleration. Two different such observers (such as two GPS satellites in orbit) have relative time dilation with their relative difference in velocity when neither is subject to inertial forces. Your hypothesis that time dilation is a result of inertial forces interacting with parts of a clock or human metabolism is not supported by observation.

 

I understand that from cosmic perspective, or even a deep space photo of sun and earth that there are are approximately 93 million "miles" (however many kilometers), each standardized earth-commensurate measures of distance. between the two bodies. You can do "thought experiments with a "photon's experience of 'no time or space' in its travel until you talk yourself out of this objectiv measure of the distance, but it remains all in your head, while the actual distance is ontologically real.

 

The distance between the earth and sun is a determination of the person who measures it. Newton believed that everyone would measure the distance equally. Einstein demonstrated that different reference frames would measure the distance differently. Observations have consistently disagreed with Newton on this and agreed with Einstein. Any philosophical interpretation should also disagree with absolute Newtonian space and agree with relativity.

 

You give the example of a "deep space photo" of the earth and sun, claiming that the distance between the two will be "objective" (absolute or fixed) at 93 million miles Your thinking appears to be that a camera far-enough away from the earth / sun distance will assuredly give this objective measure between them. This is not the case. A camera very far from the earth / sun may find the distance to be 1 million miles or 20 million miles or 2 miles or 90 million miles. It all depends on how the camera is moving relative to the earth and sun.

 

This is how our universe works. Distance, time, and simultaneity are all relative. Your objection to the reification of spacetime is agreeable in that people often take the analogy of spacetime too literally. But, you inappropriately extend this to an objection of relativity itself thinking something along the lines of: if space and time are not like the pictures in the textbook then relativity is needless and wrong.

 

Such a position is philosophically untenable.

 

Think of the magnetic field lines a person could draw around a magnet. The field lines are not real physical things. But, that doesn't mean electromagnetism isn't a real physical thing. It doesn't mean that Maxwell's theory of the electromagnetic field is wrong. You are trying to tie these two things (reification and the validity of the theory) together and its not working because the validity of the theory doesn't need reification of the field and the improper reification of the field doesn't necessitate an invalid theory.

 

~modest

[Michael Mooney]

So many points to consider... will reply later.

Late night focus on one concept::

A freefalling observer (such as a clock in orbit) feels no acceleration. Two different such observers (such as two GPS satellites in orbit) have relative time dilation with their relative difference in velocity when neither is subject to inertial forces. Your hypothesis that time dilation is a result of inertial forces interacting with parts of a clock or human metabolism is not supported by observation.

 

True, once in orbit there is no change in inertia until the clock slows down and is compared with the control stationary (no change in inertia) clock. I thought that the variable in the experiment was the boost and return (slowing on re-entry) of the orbiting clock. I was unaware of the differences in "time-keeping" of two orbiting clocks in GPS satellites. I will investigate this case if both are subject to equal changes in inertial force. (You must have mis-spoken, as both satellites have been subjected to changes in inertial force as they are are launced into orbital velocity... as compared to identical "stay-at-home" clocks.)

 

Afterthought:

If two clocks in two GPS satellites have different velocities, they have already been subjected to different acceleration, i.e. different changes in inertial force on one as compared to the other. The only true control of this variable would be if both were launched via identical force into identical orbital speeds.

What say you to this objection?

Michael

[Michael Mooney]

MM:

The Lorentze transformation *assumes* time dilation and space curvature, both of which are clearly cases of erroneous reification, as I have meticulously argued in this thead.

M:The only thing the Lorentz transformations assume is the invariance of the speed of light.

 

Sheesh! The Lorentz transformation assumes the basic tenants of relativity which include "time dilation" and "space curvature." Good grief! Do want to talk science or nit pick language precision?

 

M:

If Galilean relativity worked (or correctly described our universe), GPS satellites would not work correctly. Planes would most-likely crash into mountains killing people.

This is simply wrong. I am beginning to believe you are a master of the snow-job.

Maybe you should read the links you are offering me. I will add ("and relativity in general" to the following Wikepedia quote:

At the low relative velocities characteristic of everyday life, Lorentz invariance (and relativity in general) and Galilean invariance (and relativity in general are nearly the same, but for relative velocities close to that of light they are very different.

 

Your problem is claiming that Newton’s law of gravity and Newtonian relativity give the right answers as you do here:

 

Quote:

Originally Posted by Michael Mooney

Gravitation is a field which acts as per the universal law thereof, "directly with massiveness and inversely with distance"... Just like Newton said. He didn't like "action at a distance" either, but the equations still work, as all astronomers and "rocket scientists" know.

 

Until you can get past these basic misconceptions, your conclusions are going to continue to disagree with reality.

To what version of reality are you referring specifically? Be specific and so will I.

 

That time dilation depends on velocity rather than acceleration is proved by Bailey et al., “Measurements of relativistic time dilation for positive and negative muons in a circular orbit,” Nature 268 (July 28, 1977) pg 301.

Quote:

The experiment of Bailey et al. referenced above stored muons in a magnetic storage ring and measured their lifetime.

There is a lot of controversy over the "life expectancy of muons." For instance, how does the above experiment control for the effect of the intense magnetic field in the storage ring as effecting their "lifespan" as compared with the control muons with the same energy moving inertially? Your "is proved by" above is hyperbole in service to your bias.

 

Time dilation is shown not to be an effect of acceleration or inertial forces. It is also shown to be a real effect— regardless of how real or not-real one wishes to consider time.

Shall we abandon the common meaning of words to serve the theory of "time dilation? Given the ontological recognition that "time" is simply the "duration of a selected event" (I.e., as per "presentism"... time is not "real") how is it that some-thing not real "dilates?" What is the actual nature of the "real effect" your statement claims?

 

Also, along these same lines, please answer my "afterthought" objection (last night) to your example of two GPS with two different velocities. How were they *not* exposed to different inertial forces to achieve different velocities?

(Replay): M:

A freefalling observer (such as a clock in orbit) feels no acceleration. Two different such observers (such as two GPS satellites in orbit) have relative time dilation with their relative difference in velocity when neither is subject to inertial forces. Your hypothesis that time dilation is a result of inertial forces interacting with parts of a clock or human metabolism is not supported by observation.

MM:

If two clocks in two GPS satellites have different velocities, they have already been subjected to different acceleration, i.e. different changes in inertial force on one as compared to the other. The only true control of this variable would be if both were launched via identical force into identical orbital speeds.

What say you to this objection?

 

The distance between the earth and sun is a determination of the person who measures it. Newton believed that everyone would measure the distance equally. Einstein demonstrated that different reference frames would measure the distance differently. Observations have consistently disagreed with Newton on this and agreed with Einstein. Any philosophical interpretation should also disagree with absolute Newtonian space and agree with relativity.

From cosmic (objective, as I call it) perspective the distance between things is not dependent on the perspective of who measures it, i.e., cosmic perspective transcends relative, local perspective .

You are still unable to "wrap your head around" what I mean by cosmic/objective perspective.

 

An obvious example, quite "local": The distance from earth to moon can be very accurately determined by bouncing a laser light off a mirror on the moon and dividing the light seconds of the round trip in half. This determines the "objective" distance to the moon, regardless of the mind games you want to play with it. Same with distance between earth and sun (sans the laser and mirror... but it is no secret that the sun is 8+ light minutes distance from earth. Again, what a photon "experiences" on its journey is just another mind game disputing the objective, actual distance.

 

IGotta go.

Michael

[modest]

True, once in orbit there is no change in inertia until the clock slows down and is compared with the control stationary (no change in inertia) clock. I thought that the variable in the experiment was the boost and return (slowing on re-entry) of the orbiting clock. I was unaware of the differences in "time-keeping" of two orbiting clocks in GPS satellites. I will investigate this case if both are subject to equal changes in inertial force. (You must have mis-spoken, as both satellites have been subjected to changes in inertial force as they are are launced into orbital velocity... as compared to identical "stay-at-home" clocks.)

 

GPS satellites are time dilated every day (and hour and minute). They aren't launched into orbit every day. That only happened once. On any given day, a GPS satellite feels no inertial forces, yet they are time dilated because they have difference in relative velocity. You might be insinuating that the clock on a GPS satellite runs slow today because it felt an inertial force in the 1980's. I hope that is not the case.

 

If two clocks in two GPS satellites have different velocities, they have already been subjected to different acceleration, i.e. different changes in inertial force on one as compared to the other. The only true control of this variable would be if both were launched via identical force into identical orbital speeds.

 

The muon experiment I quoted yesterday proves that time dilation is not caused by acceleration and inertial forces—it depends only on velocity. If a person views two clocks with the same velocity that are undergoing wildly different accelerations and inertial forces (perhaps one is moving in a tight circle feeling a large centrifugal force) then the person sees both time dilated equally.

 

~modest

[modest]

The only thing the Lorentz transformations assume is the invariance of the speed of light.

Sheesh! The Lorentz transformation assumes the basic tenants of relativity which include "time dilation" and "space curvature." Good grief! Do want to talk science or nit pick language precision?

 

No. The postulates or assumptions of the Lorentz transformations and special relativity are:

1. The Principle of Relativity - The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems in uniform translatory motion relative to each other.
   
2. The Principle of Invariant Light Speed - Light in vacuum propagates with the speed c (a fixed constant) in terms of any system of inertial coordinates, regardless of the state of motion of the light source.
   

This can be seen at the link I provided yesterday or in the first section of wikipedia's article on special relativity.

 

Space curvature and time dilation are not a "basic tenant" or an assumption or a postulate of special relativity or the Lorentz transformations.

 

Time dilation and spacetime curvature are PREDICTIONS of the theory. There is a very big conceptual difference between the postulates a theory is built on (or the assumptions it makes) and the predictions made by a theory. Time dilation was predicted by relativity before it was ever observed. The only significant assumption Einstein made when formulating SR or deriving the Lorentz transformations was that all inertial observers would measure the same value for the speed of light.

 

I strongly suggest you read the wikibook on special relativity I linked earlier.

 

If Galilean relativity worked (or correctly described our universe), GPS satellites would not work correctly. Planes would most-likely crash into mountains killing people.

This is simply wrong. I am beginning to believe you are a master of the snow-job.

The link I gave you yesterday supports what I say:

The combination of these two relativistic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and

errors in global positions would continue to accumulate at a rate of about 10 kilometers each day!

 

About 10 kilometers a day (about 10 meters per minute) is indeed difference enough for planes to go crashing into mountains. This work is shown using the Lorentz transformations here:

 

http://triangulum.nl/Werkgroepen/documentatie%20werkgroepen/GPS%20essay.pdf

 

If you ask, I will do the calculations with both Newtonian relativity and special relativity.

 

:hyper: It is a

site rule

to back up claims with scientific links or references especially when asked. Can you please support your claim that GPS would work more or less correctly using Galilean transformations or Newtonian mechanics. :)

 

An obvious example, quite "local": The distance from earth to moon can be very accurately determined by bouncing a laser light off a mirror on the moon and dividing the light seconds of the round trip in half. This determines the "objective" distance to the moon, regardless of the mind games you want to play with it.

 

The amount of time it takes a laser to go to the moon and return is not absolute and depends clock measuring it and the reference frame of that clock. While one person's clock might measure 2.5 seconds, another person's clock might measure 2 seconds or 1 second, all depending on relative velocity.

 

Your "cosmic perspective" is undefined. If it is real then someone should be able to use it.

 

~modest

[Michael Mooney]

It is a site rule to back up claims with scientific links or references especially when asked. Can you please support your claim that GPS would work more or less correctly using Galilean transformations or Newtonian mechanics.

 

The badge of authority around this statement does not show on the cut-n-paste. It says "cite scientific links or go away."

 

I already cited the link that you provided that confirmed the identical results of Newtonian/Euclidean relativity with Einsteinian relativity for observations in the realm of object trajectories in the sub-light-speed realm. Satellites and their clocks are not in light speed realm. There are other possible reasons for the required clock adjustments. (ask if interested... which I doubt!)

 

I am not claiming that " GPS would work more correctly using Galilean transformations or Newtonian mechanics. " I am suggesting that there are other possible explanations for the required adjustments than making "time" or "space" a real malleable entity. (Please don't nit-pick on correct usage of 'malleable'.... curving, contracting, expanding, etc.)

 

Try to understand the difference between the ontological inquiry into time, space, and "spacetime" and the empirical/experimental specifics and attending footnotes which your "moderator's badge" seems to require in the above "site rule" ultimatum.

 

Would you mind addressing my many references to the a-priori" philosophy-of-science" question challenging the original (long ago) transition from common sense Euclidean space into non-Euclidean space... the basis of "space as something curved" and "time as something dilate-able or perhaps contract-able"?

 

I'll be back tomorrow to see if i am banned for lack of links... etc. I really don't think there is room for a free thinker in this forum. It's all mostly "textbook science" as I see it so far.

 

Please don't continue to underestimate me. I thought you liked the ontological challenge presented above in the link you provided. Then you went back to your textbook version of reality and showed me your badge of authority.

(How do you answer the baseline challenges to absurd "line curvature" (as shortest distance between two points) or the parallel line paradox of non-Euclidean space?

You don't. You always evade the question.... as well as several others I have put directly to you:

 

Are you serious that photons with eyes have an equal say on the distance between sun and earth in argument with common scientific consensus that the actual objective distance is about 8 light minutes?

In a room full of scientist you will lose the argument on the objective distance between objects in space. Relative perspectives.... observers with clocks in different frames of speed/velocity reference are not the ultimate authorities on distance between objects.

100 % of scientists will answer the question "how far away is the sun" with ... either "about 93 million miles" or " about eight light minutes."

 

I'm really tired of your bullshit. (Excuse my crass language, but I am not "nice.")

Ban me if you must to protect your textbook authority here. (Just for laughs, review the Ontology piece you gave me. The laugh is on you... pedantic, by the book scientist that you are.)

 

I already said many time that the equations of relativity are improvements over the original Newtonian/Galilean equations without the Einsteinian corrections. Still, the ontological inquiry into the actual nature of "spacetime" remains unanswered.

How is "it" different than the old-time (out of style) "aether?" Both bogus inventions of the (however genius) human mind.

 

(Aside... This is an obscene personal brag. Einstein, they say, had an IQ of about 160. My WAIS was 178, and my SBIS was 170.

I reveal this "mine is bigger' obscenity because I think I will be banned since i did not provide the "proof" that GPS satellites do not "prove" that "time" (what is that stuff?) "dilates" (expands and contracts... or what?!)

 

I challenge the BASICS of this whole "spactime continuum" on ontological grounds, and all I get is pre-cooked textbook science ASSUMING that the transition from Euclidean to non-Euclidean space... and all cosmology... is "correct"... as everybody knows... for over a hundred years now.

 

I'll be going now. I debunked Hawking six months before he recanted.... on "Myspace"... look it up...

and I was banned from myspace in the process. "Granny" doesn't tolerate intense debate... "Be Nice or Be Banned" was "her motto."

But I gave the lie to his nonsense long before he joined the "M-theory" boys (and endorsed their book.)

His singularity theory of cosmic origin was nonsense from the beginning: " Infinite density of mass in zero volume of space."

(The genius mathematician had a blind spot in the eye of common sense!)

 

I called him on it. No reply, but he was wrong. Myspace archives will verify what I say here, long before he "recanted."

I say that you, modest, are a textbook regurgitating robot. Probably got your PhD that way.

Sorry you lost your faculty of critical thinking along the way.

 

Good bye.

Michael

[pamela]

and sorry Michael, that you never developed manners......Your arrogance and condescending attitude has been prevalent though out this entire thread. You repeatedly insult and attack the people of this forum.Not free thinkers? or is it just that they do not bow down to your almighty speculations.Hawking not responding?

Well, he is a gentleman, and was probably tired of your abuse; and having manners, chose to be polite and remain silent.

This forum is for discussions not attacks. Please learn the difference; should not be difficult for you with that IQ.

[Michael Mooney]

Hi Essay,

Hope you don't mind my posting my PM reply to you here, as it addresses the forum in general as well as your question.

 

Looks like I'm outta here.

Time is a human artifact created by the stopwatch principle. Now is ongoing everywhere. There is no time between "future" (not yet present) and "past" (not still present.)

Ontologically speaking, time is not real. Therefore "it" does not dilate. Clocks run slower as they are exposed to changes in inertia. Apparently the differences in their accuracy persists in orbital free fall in proportion to their original differences in launch force.

 

I suspect that, since all things are made of "oscillating" energy patterns that all things are effected by changes in inertial force, including the rate of human metabolism, whether on the molecular or atomic level (as per the slowed rate of cesium decay in atomic clocks subjected to inertial change.)

 

Please convey my apology to modest. I was here to address the ontology of space (as emptiness) and time as above, not to get into personal insult slinging, even though several here including modest have been consistently disrespectful and condescending to me, as I have the audacity to challenge non-Euclidean "spacetime" which "everyone has known for a hundred years" has replaced Euclidean, according to Modest.

(See my extensive critique of "The Ontology and Cosmology of Non-Euclidean Geometry"... which no one here would touch with a ten foot pole.)

 

Good luck and goodbye.

Being known by friends and colleagues as a "brilliant man" who questions authority, I have had quite enough of being told how stupid I am.

 

What the hell... Ill post this myself as my finale.

Michael

[modest]

The badge of authority around this statement does not show on the cut-n-paste. It says "cite scientific links or go away."

You can make the exclamation point emoticon by typing :phones: or clicking [more] under the smileys that are shown when you're writing your post. None are a badge and none say 'go away' and I'm quite sure I've never used one intending it to be taken that way.

 

I already cited the link that you provided that confirmed the identical results of Newtonian/Euclidean relativity with Einsteinian relativity for observations in the realm of object trajectories in the sub-light-speed realm. Satellites and their clocks are not in light speed realm.

 

But, no link you've provided has said "identical results... in the sub-light-speed realm." nor do I think any serious scientific source say such a thing. Your link says:

 

At the low relative velocities characteristic of everyday life, Lorentz invariance and Galilean invariance are nearly the same, but for relative velocities close to that of light they are very different.

 

Galilean invariance - Wikipedia, the free encyclopedia

 

I don't think it's necessary for me to explain the difference between "identical" and "nearly the same", but I will explain that difference in the case of GPS satellites as I think that's where the problem is.

 

The difference in velocity between a GPS satellite and a person on the surface of the earth may only be 14,000 km/hr which is very slow compared to the speed of light. At speeds this slow, the answers given by special relativity are nearly the same as good old fashion Galilean relativity, but they are not the same. Galilean relativity would predict no time dilation while SR predicts time dilation of 7 microseconds per day.

 

The difference here is not much when compared to everyday human experience, but GPS requires extraordinary (nanosecond) accuracy. If GPS satellites were off by just a few microseconds, a person's hand-held GPS navigator would be off by kilometers. So, it is necessary to recognize that Galilean invariance is not the same as Lorentz invariance even at low relative velocities.

 

At speeds of half or 4/5ths the speed of light the effects become very, very significant. And we (as humans) have accelerated particles from rest to .99... times the speed of light and we've seen the result of relativity at those speeds too.

 

There are other possible reasons for the required clock adjustments. (ask if interested... which I doubt!)

 

What would be interesting is if you could devise some experimental way of showing the reason for time dilation. A person could say it's the result of just about anything—I could say it's the result of conservation of energy :confused:

 

What we need is a way to test whatever explanation we come up with.

 

I am not claiming that " GPS would work more correctly using Galilean transformations or Newtonian mechanics. " I am suggesting that there are other possible explanations for the required adjustments than making "time" or "space" a real malleable entity. (Please don't nit-pick on correct usage of 'malleable'.... curving, contracting, expanding, etc.)

 

That's good to hear. You'll notice Einstein's original paper on Special Relativity does not give a reason for time dilation (or other special relativistic effects), other than the invariance of the speed of light. It is possible to derive the Lorentz transformations (which predict time dilation) without considering space malleable or curving or using Minkowski spacetime at all.

 

Einstein considered time to be what a clock measures—the measured duration between two local events. He considered space to be what a rod measures—the measured distance between two things. Consider that the laws of physics work for everyone and that the speed of light is equal for everyone and you can derive special relativity. No more is required. No curved spacetime, no malleable entity, etc.

 

Having a philosophical problem with spacetime does not require SR to be wrong. As I've said previously, the idea isn't to find out if SR and GR are correct. They've been tested and verified to very high precision, so we know they're 'correct'. The idea is to figure out why they're correct or why they work... to figure out what the observations which are predicted and described by SR and GR mean in an ontological sense. In the case of general relativity, that is what The Ontology and Cosmology of Non-Euclidean Geometry looks at.

 

Try to understand the difference between the ontological inquiry into time, space, and "spacetime" and the empirical/experimental specifics and attending footnotes which your "moderator's badge" seems to require in the above "site rule" ultimatum.

 

The site rule requiring members to support their claims applies to ontological inquiries.

 

Would you mind addressing my many references to the a-priori" philosophy-of-science" question challenging the original (long ago) transition from common sense Euclidean space into non-Euclidean space... the basis of "space as something curved" and "time as something dilate-able or perhaps contract-able"?

 

I don't know what time is in an ontological sense. My human brain doesn't understand it. I think it's impossible to fully describe any real happening in our universe without using time and space and that massive bodies make objects act like time and space are curved into one another. But, the true nature of what is being curved or what our geometry represents, I don't know.

 

I'll be back tomorrow to see if i am banned for lack of links...

 

You have received no infraction and I assure you, no one has considered banning you. A moderator pointed out a site rule, which you should do your best to follow—that is all.

 

(How do you answer the baseline challenges to absurd "line curvature" (as shortest distance between two points) or the parallel line paradox of non-Euclidean space?

You don't. You always evade the question.... as well as several others I have put directly to you:

 

Consider two people that leave earth simultaneously and arrive on the moon simultaneously. In other words: they are physically touching exactly when they leave earth and they physically bump into each other when they land on the moon. What is the quickest or shortest path to the moon with these constraints?

 

If one person travels in a straight line directly to the moon while the other person travels to a near-by star such as Alpha Centauri on his way to the moon, but they both land on the moon simultaneously then which has spent less time traveling? Which was the shortest path?

 

Oddly enough, it is the person who went the roundabout way to get to the moon. The person traveling straight to the moon might think the trip took 10 days while the other astronaut might think the trip took 10 seconds. This is what is meant by "the shortest distance between two points is not a straight line".

 

If you draw the situation above as a graph on a piece of Euclidean paper then it doesn't work right (or look right). If you could draw the graph on a piece of hyperbolic paper then it would look and work correctly. This is where people get the idea of curved spacetime in special relativity.

 

Are you serious that photons with eyes have an equal say on the distance between sun and earth in argument with common scientific consensus that the actual objective distance is about 8 light minutes?

 

A photon is not in an inertial reference frame so it's an odd situation to consider. But, there are also an infinite number of inertial reference frames where the distance between two bodies would be measured differently.

 

I'm really tired of your bullshit. (Excuse my crass language, but I am not "nice.")

Ban me if you must to protect your textbook authority here.

 

I think you're misunderstanding my intention here. I'm not trying to prove you wrong or prove "textbook authority" correct. I'm explaining why scientists and textbooks have come to the conclusions they have. I would hope you could find this useful.

 

~modest

[Essay]

...fyi:

I hope to still be able to add a bit to this "spacetime" discussion ...later.

 

But I need to ask you about (as I'm catching up on the past few pages) your mention of metabolism.

 

....something along the lines of: suspecting that human metabolism may slow down in response to inertial forces....

 

Really? As in an explanation to the twins paradox--the travelling twin ageing less than the other?

Would this be as compared to a glass breaking?

...so if someone experiencing time dilation were to drop a glass, it would break normally (relative to their slowed metabolism)?

 

Surely I'm misunderstanding that you are distinguishing between atomic and biochemical processes.

My PM was prompted by your line:

"I suspect that human metabolism also slows down under exposure to the forces of acceleration /deceleration."

from post #133, http://hypography.com/forums/philosophy-of-science/17037-what-is-spacetime-really-14.html#post247329

 

...it's worded as if there is the possibility of metabolism being affected differently than other physical processes.

 

Thanks for clarifying that point about "metabolism." I didn't think you were saying that metabolism was affected by dilation any differently than other physical processes (a glass breaking or a clock running), but I had to ask.

===

 

If it were acceleration causing the effect, I'd have thought that deceleration would cancel the effect, but I suppose any change (plus or minus) could have the same dilation effect.

 

But velocity seems to be the key, because it's how long one is travelling at a given velocity near "c" that determines how much more the twin on Earth has aged, isn't it?

===

 

But regardless of all the details of that, I'm still not sure that I see what the difference is between calling "it" spacetime, or calling it empty space filled with a networking web of fields.

 

Sorry I'm not a physicist, or I'd probably know the answer; but if you want to explore the physics of CO2 and infrared radiation, I could probably do better.

 

Later,

~ :confused:

 

p.s. Please include citations when you refer back to stuff you wrote previously.

I'm sure I've read it, but I can't recall to which version of the point you are referring, or how it was contextualized.

(...or words to that effect)

... or if nothing more, a review might be helpful in light of all the additional background (or back-and-forthground).

Just a post # will work.

 

~SA

 

Time is a human artifact....

Ontologically speaking, time is not real.

...and you know I feel the same about empty space.

Between us, we have spacetime pretty well covered, eh?

:phones:

[pamela]

Michael, I certainly hope that your goodbye was not final. No one here thinks that you are stupid nor have I seen anyone call you that. You are quite intelligent and that is reflected in your posts. This thread has been one of the most informative ones that I have seen. I have gained much knowledge and insight from everyone's posts here, including yours. Please reconsider, and stay, I am sure you have much to offer this forum. My post was a little abrasive, and for that I apologize.

[Michael Mooney]

Modest,

I have reconsidered my resignation from this forum. I will reply to several of your comments, but tonight (late and somewhat inebriated... good night out on the town!) I will focus on one statement:

 

I don't know what time is in an ontological sense. My human brain doesn't understand it. I think it's impossible to fully describe any real happening in our universe without using time and space and that massive bodies make objects act like time and space are curved into one another. But, the true nature of what is being curved or what our geometry represents, I don't know.

I do know what time is (is not, actually) in the ontological sense. Seems you have not heard a word I've said on the subject. I will reveal a secret. I've spent over 14,000 hours in meditative stillness (39 yrs, an hour a day "sitting.") There is a state of transcendence beyond what the human brain is capable of understanding. Not "science" in the modern definition but more in the nature of the ancient "sacred science" which also included inspiration.

 

My inspiration throughout all these meditative years has embraced an understanding of "time" as I've presented it in this thread. You seem to be incapable of understanding what you call "presentism" as anything but a questionable concept (which you prefer over the alternative... in which past and future are real and accessible). I know that time is a human concept... 'clocking' event duration... the result of selecting an "event" and "timing" its duration. In Nature, if you really contemplate it, there is no "time" but only the perpetual now transcending local "perspective" and "time dilation" (as relativity has created the special mindset.)

 

You say: " I think it's impossible to fully describe any real happening in our universe without using time and space and that massive bodies make objects act like time and space are curved into one another. But, the true nature of what is being curved or what our geometry represents, I don't know."

I say that the universal now, from cosmic perspective (with which I am very familiar... as intrinsic to transcendence of personal, local perspective) "sees" space as infinite (unbounded) emptiness and time as a human "stopwatch" perspective.

Massive objects pull on one another without the need for the human concept of spacetime to be an intermediate "fabric" however literal or metaphoric. (Can you even imagine space as emptiness, given your "educational" indoctrination as to how it must be 'something' with various properties like curvature to explain the simple fact that objects *in space* often have curved trajectories as effected by gravity as a force operating through *empty space" (which seems impossible to you?)

 

Must quit. Back tomorrow.

Michael

[Michael Mooney]

Modest:

I don't think it's necessary for me to explain the difference between "identical" and "nearly the same", but I will explain that difference in the case of GPS satellites as I think that's where the problem is.

 

 

The difference in velocity between a GPS satellite and a person on the surface of the earth may only be 14,000 km/hr which is very slow compared to the speed of light. At speeds this slow, the answers given by special relativity are nearly the same as good old fashion Galilean relativity, but they are not the same. Galilean relativity would predict no time dilation while SR predicts time dilation of 7 microseconds per day.

 

The difference here is not much when compared to everyday human experience, but GPS requires extraordinary (nanosecond) accuracy. If GPS satellites were off by just a few microseconds, a person's hand-held GPS navigator would be off by kilometers. So, it is necessary to recognize that Galilean invariance is not the same as Lorentz invariance even at low relative velocities.

 

At speeds of half or 4/5ths the speed of light the effects become very, very significant. And we (as humans) have accelerated particles from rest to .99... times the speed of light and we've seen the result of relativity at those speeds too.

 

Quote:

Originally Posted by Michael Mooney View Post

There are other possible reasons for the required clock adjustments. (ask if interested... which I doubt!)

What would be interesting is if you could devise some experimental way of showing the reason for time dilation. A person could say it's the result of just about anything—I could say it's the result of conservation of energy

 

What we need is a way to test whatever explanation we come up with.

 

I take your point that "nearly the same" is not "identical" and that Lorentz invarience yields the required precision that Gallilean invarience does not.

 

Given what I know about "time" as not a reality in and of itself, my criticism is focused on the constant reification of "it" as something which can "dilate"... as "time dilation" is assumed as a fact, a given, as you do again above.

 

What would be interesting is if one could devise some experimental way of showing the reason for the required clock adjustements without automatically calling the effect " time dilation" as if we all know that "time" expands and contracts. The first step is to stop reifying time. The next step is to investigate why clocks at different velocities relative to each other "keep time" differently. The only difference I can see is the difference in inertial forces to which each is subjected to get them going at different velocities.

If the force of change in inertia is the ultimate reson that different clocks keep time differently, then this could be tested via gradual increments in accelleration, for instance, all the while testing for changes in the rate the two clocks are "ticking" (or decaying their cesium... whatever.)

 

If inertial changes effect the rate of oscillation at the atomic level, then perhaps humans "age more slowly" as they are accellerated as well. This could be tested via subjecting a subject to an astronaught training G-force centrifuge for long periods while his identical twin is not. Then tests of metabolic rate might show a difference between the two.

 

Consider two people that leave earth simultaneously and arrive on the moon simultaneously. In other words: they are physically touching exactly when they leave earth and they physically bump into each other when they land on the moon. What is the quickest or shortest path to the moon with these constraints?

 

If one person travels in a straight line directly to the moon while the other person travels to a near-by star such as Alpha Centauri on his way to the moon, but they both land on the moon simultaneously then which has spent less time traveling? Which was the shortest path?

 

Oddly enough, it is the person who went the roundabout way to get to the moon. The person traveling straight to the moon might think the trip took 10 days while the other astronaut might think the trip took 10 seconds. This is what is meant by "the shortest distance between two points is not a straight line".

 

If you draw the situation above as a graph on a piece of Euclidean paper then it doesn't work right (or look right). If you could draw the graph on a piece of hyperbolic paper then it would look and work correctly. This is where people get the idea of curved spacetime in special relativity.

 

From "cosmic perspective" ("objectively" speaking as I see it), its quite straight forward. The shortest route to the moon is the the one that landed the "Eagle" there. That is why they didn't go by way of Alpha Centauri. If the race was on and they sent some kind of ship to A.C., even a ficticious ship that could travel at light speed, the direct-to-the-moon flight (say at light speed too, just to keep an "even playing field) would arive in a couple of seconds or so, while the flight via A.C. would take a few years.

Yours is a mind game, while I'm talking about the "real world."

I'll see ya on the moon... I'll even give you an 8 year head start and have plenty of time to set up a comfy pop-up moon base and bake a cake!

 

Michael

[Moontanman]

Modest:

 

 

I take your point that "nearly the same" is not "identical" and that Lorentz invarience yields the required precision that Gallilean invarience does not.

 

Given what I know about "time" as not a reality in and of itself, my criticism is focused on the constant reification of "it" as something which can "dilate"... as "time dilation" is assumed as a fact, a given, as you do again above.

 

What would be interesting is if one could devise some experimental way of showing the reason for the required clock adjustements without automatically calling the effect " time dilation" as if we all know that "time" expands and contracts. The first step is to stop reifying time. The next step is to investigate why clocks at different velocities relative to each other "keep time" differently. The only difference I can see is the difference in inertial forces to which each is subjected to get them going at different velocities.

If the force of change in inertia is the ultimate reson that different clocks keep time differently, then this could be tested via gradual increments in accelleration, for instance, all the while testing for changes in the rate the two clocks are "ticking" (or decaying their cesium... whatever.)

 

If inertial changes effect the rate of oscillation at the atomic level, then perhaps humans "age more slowly" as they are accellerated as well. This could be tested via subjecting a subject to an astronaught training G-force centrifuge for long periods while his identical twin is not. Then tests of metabolic rate might show a difference between the two.

 

 

 

From "cosmic perspective" ("objectively" speaking as I see it), its quite straight forward. The shortest route to the moon is the the one that landed the "Eagle" there. That is why they didn't go by way of Alpha Centauri. If the race was on and they sent some kind of ship to A.C., even a ficticious ship that could travel at light speed, the direct-to-the-moon flight (say at light speed too, just to keep an "even playing field) would arive in a couple of seconds or so, while the flight via A.C. would take a few years.

Yours is a mind game, while I'm talking about the "real world."

I'll see ya on the moon... I'll even give you an 8 year head start and have plenty of time to set up a comfy pop-up moon base and bake a cake!

 

Michael

 

Micheal, I think that in my own slow methodical way I do see what you mean, time is human construct, there is no real meaning to time, you cannot measure time the same way you measure, say the diameter of the Earth. time has no definite measure, we measure "time" via completely artificial means that have no natural constraints. But so far the our artificial measurement of time does give a pretty good approximation of reality. Just because we cannot pin down exactly what times is and how it changes doesn't mean it's not a real constraint just like the diameter of the earth. Do you have a better idea of what time is? I think time is a dimension, just like the other three. In the same way a cube can contain an infinite number of two dimensional planes a Four D space can contain an infinite number of three D moments. Of course that is my idea and I have no links to back it up.

[Essay]

The only difference I can see is the difference in inertial forces to which each is subjected to get them going at different velocities.

If the force of change in inertia is the ultimate reson that different clocks keep time differently, then this could be tested via...

...but what about my comment in post #146:

If it were acceleration causing the effect, I'd have thought that deceleration would cancel the effect, but I suppose any change (plus or minus) could have the same dilation effect.

 

But velocity seems to be the key, because it's how long one is travelling at a given velocity near "c" that determines how much more the twin on Earth has aged, isn't it?

===

 

It seems to me that each "orbit" of our galaxy should have it's own time dilation constant.

As our solar system is in a given orbit around the Milky Way, so other stars closer in or farther out from the center will have their own "orbits" around the center of the galaxy. Wouldn't each larger circumference have it's own time dilation, relative to other "orbits?"

 

~ :weather_snowing:

[modest]

I've spent over 14,000 hours in meditative stillness (39 yrs, an hour a day "sitting.")

 

I've been known to meditate a time or two myself. I can give you a zen-like riddle submitted for meditation:

While you spent 14,000 hours in meditative stillness, I took many car rides, plane flights, and other transient shuffles of everyday life. Moving as I have, I experienced 13,999 hours compared to your 14,000 hours.

 

My experience was very real to me, so I demand the cosmos accept it as the objective truth. Your experience was equally real to you and you likewise demand the cosmos accept it as the objective truth. But, which of our experiences does the cosmos prefer?

All the crazy scientists out there with their crazy mind games have come up with the idea that there is *no* preferred reference frame—not even the one that says the sun is 93 million miles away from the earth. Everything is relative... It's very Buddhist.

 

You seem to be incapable of understanding what you call "presentism" as anything but a questionable concept (which you prefer over the alternative... in which past and future are real and accessible).

You lost me. Are you saying that I think the past and future are accessible? Or, that relativity requires that?

 

I know that time is a human concept... 'clocking' event duration... the result of selecting an "event" and "timing" its duration. In Nature, if you really contemplate it, there is no "time" but only the perpetual now transcending local "perspective" and "time dilation" (as relativity has created the special mindset.)

 

I agree that time is a human concept, just like gravity. The question is what (if anything) these human concepts represent. Does the human concept of time represent something real? If so, what is its nature? Likewise, what is the nature of gravity?

 

You say: " I think it's impossible to fully describe any real happening in our universe without using time and space and that massive bodies make objects act like time and space are curved into one another. But, the true nature of what is being curved or what our geometry represents, I don't know."

I say that the universal now, from cosmic perspective (with which I am very familiar... as intrinsic to transcendence of personal, local perspective) "sees" space as infinite (unbounded) emptiness and time as a human "stopwatch" perspective.

 

I agree that space is most likely infinite and unbound. I disagree that your perspective is the cosmic perspective. For example, you're quite sure that the cosmic perspective has the earth 93 million miles from the sun. But, the only reason you think the earth is that far from the sun is because you are in earth's reference frame. Were you in the center of the galaxy (and motionless to it) you would measure that distance differently. Human arrogance has historically believed that earth is somehow preferred by the cosmos. But, relativity tells us that even things like duration and distance are relative.

 

Distance and duration as I see it is not distance and duration as you see it. Two things that happen simultaneously from my point of view, may not happen simultaneously from your point of view. Both of us are equally right and the cosmos doesn't have a preferred or absolute preference for either of us. The rules of the universe and the laws of physics work the same for both of us. This is relativity.

 

Massive objects pull on one another without the need for the human concept of spacetime to be an intermediate "fabric" however literal or metaphoric.

 

Massive objects can do many things without the need for human concepts. The idea is to create a human concept that explains and describes what is happening between massive objects—to understand it ontologically.

 

(Can you even imagine space as emptiness, given your "educational" indoctrination as to how it must be 'something' with various properties like curvature to explain the simple fact that objects *in space* often have curved trajectories as effected by gravity as a force operating through *empty space" (which seems impossible to you?)

 

Can you explain "affected by gravity" and "operating through empty space" ontologically?

 

I take your point that "nearly the same" is not "identical" and that Lorentz invarience yields the required precision that Gallilean invarience does not.

 

That's good. The variables in the Lorentz transformations are time, distance, and velocity. Why do you think the first two are relative depending on the third?

 

Given what I know about "time" as not a reality in and of itself, my criticism is focused on the constant reification of "it" as something which can "dilate"... as "time dilation" is assumed as a fact, a given, as you do again above.

 

You've defined time as duration. Would you rather call it duration dilation?

 

Also, if you object to time being used in time dilation, do you also object to it being used in velocity, acceleration, movement, and every other physical law? If I said something was going 3 meters per second would you object to me using seconds because time isn't real?

 

What would be interesting is if one could devise some experimental way of showing the reason for the required clock adjustements without automatically calling the effect " time dilation" as if we all know that "time" expands and contracts.

 

But, it isn't just clocks that are dilated, or people or waves, or whatever... it's everything. Any and all possible ways of measuring duration are dilated by relative velocity. As we humans have decided "duration" is called "time" then it is indeed time that is being dilated—any and all measures of time.

 

What do you think is being dilated?

 

The only difference I can see is the difference in inertial forces to which each is subjected to get them going at different velocities. If the force of change in inertia is the ultimate reson that different clocks keep time differently, then this could be tested via gradual increments in accelleration, for instance, all the while testing for changes in the rate the two clocks are "ticking" (or decaying their cesium... whatever.)

 

We've been over this.

 

Does a clock's acceleration affect its timing rate?

 

The answer is no—acceleration does not affect timing.

 

If inertial changes effect the rate of oscillation at the atomic level, then perhaps humans "age more slowly" as they are accellerated as well. This could be tested via subjecting a subject to an astronaught training G-force centrifuge for long periods while his identical twin is not. Then tests of metabolic rate might show a difference between the two.

 

This is the muon experiment I quoted and linked earlier (albeit they used muons rather than people as people would be liquefied from going around in a circle so fast). The results of the experiment showed that time dilation depended on velocity and was not affected by acceleration (or other higher derivatives of velocity).

 

From "cosmic perspective" ("objectively" speaking as I see it), its quite straight forward. The shortest route to the moon is the the one that landed the "Eagle" there. That is why they didn't go by way of Alpha Centauri. If the race was on and they sent some kind of ship to A.C., even a ficticious ship that could travel at light speed, the direct-to-the-moon flight (say at light speed too, just to keep an "even playing field) would arive in a couple of seconds or so, while the flight via A.C. would take a few years.

 

You must have misunderstood. Both ships in my thought experiment took off and landed simultaneously... you're talking about who lands first in a race...?

 

~modest

[Michael Mooney]

Moontanman:

Micheal, I think that in my own slow methodical way I do see what you mean, time is human construct, there is no real meaning to time, you cannot measure time the same way you measure, say the diameter of the Earth. time has no definite measure, we measure "time" via completely artificial means that have no natural constraints. But so far the our artificial measurement of time does give a pretty good approximation of reality. Just because we cannot pin down exactly what times is and how it changes doesn't mean it's not a real constraint just like the diameter of the earth. Do you have a better idea of what time is? I think time is a dimension, just like the other three. In the same way a cube can contain an infinite number of two dimensional planes a Four D space can contain an infinite number of three D moments. Of course that is my idea and I have no links to back it up.

 

(" Do you have a better idea of what time is?)

Two answers to consider simultaneously...

One:

It is the *concept/measure* of event duration, like

A: one rotation of earth (day and standardized divisions thereof... hours, minutes, seconds... nanoseconds)

B: one earth orbit around sun (measured three different ways giving three technically different *spans of time*)

C: the great cycle of the precession of the equinox

D: a complete "bang/crunch" cycle, if my favorite comology is true...

...You get the idea.

Two: Now, the present is always present, not sliced into units of time in the real world/cosmos. As I've said many times, future is not yet real and present and past is not still real and present, and there is no "time" between future and past. Therefore "time" is not a natural reality in the strict ontological sense of what is real.

So, "spans of time", as above are as real as we make them. There is no cosmic counter clicking at every complete earth rotation, year, etc. Yet we can "be on time" to work by common consensus on the convention, time. and we can plug in "time" as a component of velocity and calculate and execute a round trip to the moon.

 

It is also conventional to call "time" the fourth dimension added to the obvious spacial three which describe volume. Then we can avoid having two airplanes at the same coordinates in air-space at the same time. A very useful convention.

But it doesn't expand and contract as an actual entity of any kind... See Two above.

 

As to your last proposition:

In the same way a cube can contain an infinite number of two dimensional planes a Four D space can contain an infinite number of three D moments.

...

 

The metaphore has the sound of a sensible extrapolation... "if, then" in 3-d, so why not extent the same concept to "an infinite number of three D moments?"

Not sure what you mean by a 3-D moment.Certainly a split second in time is enough to keep two airplanes from crashing, as in my example above. And there is no limit or boundary to the empty space which our cosmos occupies. "The end of space" is a concept not well conceived.

So there is no limit to the possible number of cosmi (with defined shapes and boundaries as actual materials) which might lie beyond the limit of our cosmic event horizon.

 

Thanks for the reply.... and the "exercise."

 

Michael