Ontology of time

[owl]

Swansont wrote:

"Clocks "tick" at different rates in different inertial circumstances, as proven by many experiments. does not specifically address the issue of whether it's a mechanical issue of the clock. But this issue has not been ignored — different types of clocks have been tested, and they all show the time dilation effect. So we conclude that the timing changes are due to the effects of relativity. "

 

I'm trying to get at the ontolology of "time," like, what is "it" besides event duration between designated instants?

I know that our most sophistcated clocks show what has come to be known as "time dilation," but how is that different than, as above, the fact that they "keep time" differently (slow down or speed up) in different inertial environment

 

Clocks keeping time at different rates is a different issue than asserting that "time itself" is an actual medium/entity which differes in each and every local inertia situation.

I hope I'm making this distinction clearly. The ontology of time is a deep subject and relativity does not have a lock on time as a malleable medium in an of "itself," which clocks simply measure.

 

Even the debate about a "global time structure" shed light on the assumption of relativity that local inertial frames of reference are the end all of the nature of time, space and the universe.

BTW, I am not advocating that time is a "structure" but more like this: It is now everywhere (ongoing, perpetually), and time is an artifact of measurement, i.e., the duration of a given event between two designated instants.

 

What say you?

Respectfully,

Owl

[ydoaPs]

Owl, your questions are more suited for the Philosophy forum.

 

I'm trying to get at the ontolology of "time," like, what is "it" besides event duration between designated instants?

Why must it be more than it is? Time is to states as space is to objects. Like distance(space) is the separation between objects within a given state, duration(time) is the separation between states themselves. The magnitudes of both distance and duration depend on the energy and chosen reference frame. Since time and space are so similar, we can take a larger picture here and take all the states together as a whole block of spacetime.

 

For a good primer on the philosophy of space and time, I'd suggest Four-Dimensionalism by Theodore Sider

 

Swansont wrote:

"Clocks "tick" at different rates in different inertial circumstances, as proven by many experiments. does not specifically address the issue of whether it's a mechanical issue of the clock. But this issue has not been ignored — different types of clocks have been tested, and they all show the time dilation effect. So we conclude that the timing changes are due to the effects of relativity. "

This site employs a quote feature so that it is more easily discernible which portions of a post are quoted material. If you would like information on this feature or one of many other features of the site, we do have a tutorial.

[owl]

Owl, your questions are more suited for the Philosophy forum.

 

Why must it be more than it is? Time is to states as space is to objects. Like distance(space) is the separation between objects within a given state, duration(time) is the separation between states themselves. The magnitudes of both distance and duration depend on the energy and chosen reference frame. Since time and space are so similar, we can take a larger picture here and take all the states together as a whole block of spacetime.

 

For a good primer on the philosophy of space and time, I'd suggest Four-Dimensionalism by Theodore Sider

 

 

This site employs a quote feature so that it is more easily discernible which portions of a post are quoted material. If you would like information on this feature or one of many other features of the site, we do have a tutorial.

 

ydoaPs,

Thanks for the tutorial link on quoting and the Sider reference on 4-D ondology.

Seems I'll have to log 30 posts before I can take my 'ontology of time' inquiry to the philosophy forum. That's OK... I've got time!

I did read the three reviews of the Sider book. One comment on the following from the Perrine review:

 

"Four-Dimensionalism holds (roughly) that, just as you have spatial parts--e.g. hands, cells, simples, etc.--you have "temporal" parts. A temporal part is a part of you that exists at a certain time in your existence. A consequence of this view is that, at a particular moment, you don't "wholly" exist, because your existence is spread out in time. (Four-Dimensionalism contrasts with Three-Dimensionalism, which holds that you "wholly exist" at every moment you exist.)

 

It seems quite "far fetched" to assert that we don't fully exist in the ongoing present because our existence is "spread out in time." But I would need to get and read the book to give it a fair review myself. Maybe, eventually.

Meanwhile my posts above in this thread give a fair summary of the ontology of time as I see it.

I really don't understand your question, "Why must it be more than it is?" My ontological objection to "time dilation" is that the concept gives "time" a reality as an entity that speeds up and slows down rather than just the obvious fact that clocks speed up and slow down in different inertial environments.

Thanks for the opportunity to address the ontology of time and space so far. I don't know why there is a 30 post requirement as above, but, of course, I will comply.

Owl

[ydoaPs]

My ontological objection to "time dilation" is that the concept gives "time" a reality as an entity that speeds up and slows down rather than just the obvious fact that clocks speed up and slow down in different inertial environments.

It's not that time 'speeds up' or 'slows down' depending on the reference frame. It's that the magnitude of the entire separation(called the spacetime metric) changes; the separation between individual states included.

Edited February 1, 2011 by ydoaPs

[owl]

It's not that time 'speeds up' or 'slows down' depending on the reference frame. It's that the magnitude of the entire separation(called the spacetime metric) changes; the separation between individual states included.

This really gets down to the ontology of "spacetime" as a metric, and the question is how well the metric, as an abstract map fits the territory being mapped.

What does it mean to say that the magnitude of the entire separation (spacetime metric) changes?

What is an individual state... a local "time environment" (with what boundaries) for an indefinite number of individual locations and inertial states?

 

There is a gap here between said abstract "metric" and the matter/energy fields they attempt to describe, and the former is ontologically confused with the latter until ontology clearly sorts it out.

The latter is my focus, my avid interest in clarifying at least the language of relativity which calls "time" a variable as well as space/distance, depending on observational perspective, as if there were no objective world/cosmos without our observations, measurements, and timing devices.

 

The whole discussion of the ontology of space, time, and spacetime, is the collective effort to address these questions. I look forward to qualifying for such discussion in the appropriate context, philosophy of science, specifically the above ontology.

Thanks.

Owl

[ydoaPs]

There is a gap here between said abstract "metric" and the matter/energy fields they attempt to describe

The same could be said of the words you're typing. The difference is that the mathematical descriptions are more accurate and testable. The fact is that time and space are so closely related that we can extremely accurately treat them as one object. General relativity is probably the best tested theory of all time.

 

Time is the separation between states, and the mathematics and tests based on said mathematics reflect that.

 

 

 

as if there were no objective world/cosmos without our observations, measurements, and timing devices.

Observers need not be sentient beings; a proton interacting with an electron is an observer of that electron.

[Marat]

A lot has been written about Einstein's debt to Ernst Mach, a positivist philosopher and physicist, in his development of relativity theory. What is real according to relativity theory depends on what can be measured: there is no distinction between what something is (its ontology) and how it is measured (operational positivism). So if time dilation can be measured only by the slowed mechanical action of clocks, then that is what time dilation is. There is no 'time' lying underneath 'time measurement' whose ontology-in-itself has to be determined -- since if there was, what would measure it?

[owl]

The same could be said of the words you're typing. The difference is that the mathematical descriptions are more accurate and testable. The fact is that time and space are so closely related that we can extremely accurately treat them as one object. General relativity is probably the best tested theory of all time.

 

Time is the separation between states, and the mathematics and tests based on said mathematics reflect that.

 

 

 

Observers need not be sentient beings; a proton interacting with an electron is an observer of that electron.

Regarding your second statement, I will (again?) quote Kelley Ross from his Ontology and Cosmology of Non-Euclidean Geometry:

"Just because the math works doesn't mean that we understand what is happening in nature. Every physical theory has a mathematical component and a conceptual component, but these two are often confused. Many speak as though the mathematical component confers understanding..."

 

Then to Deiks from the Ontology of Spacetime.

He cites cites Brown and Pooley who state that “ …The physical laws do the real explanatory work, not space and time.”… contrasting with (Deiks’ words)” the usual special relativity of Lorentz invariance as a consequence of the symmetry properties of Minkowski spacetime."

 

Deiks summarizes this debate as follows: (If Brown and Pooley are right)…”There is no causal mechanism involved: Spacetime does not send signals to which particles respond. More generally, exactly how does spacetime inform the laws of nature? Failing a detailed account of what the purported explanation consists in, it can hardly be maintained that the existence of space and time is the only plausible conclusion"...

 

The above ontological perspectives are representative of many other papers from the conferences on the ontology of spacetime.

To put it simply, mass curving spacetime (as an abstract metric or as a substantive medium) is not the only explanation for how gravity works. The virtual particles of quantum mechanics is another, but this introduces the quandry of mystery called "action at a distance" for which there is no explanation.

The trouble with all, "Time is..." statements is that the ontology of time is not a settled debate. You say, "Time is the separation between states," and I say time is the duration of events between two designated instants. Maybe they mean the same thing, but if time is just an artifact of measurement... "time is what clocks measure," then ontologically it is not an agent of or influence on events but just the assignment of "units of time" to event duration.

 

So if space is the volume in which objects and forces exist and move, and time is duration from any one "now" to another, how does that make "spacetime" into a medium with curvature which controls the movement of things observed.

I think this is a fair question which deserves an answer from relativity theorists such as yourself.

 

Finally I know that "Observers need not be sentient beings." That is why I have used "frame of reference" synonymously with "observer." Yet, even as an abstract, relativity claims that distances through space vary "for observer A as compared with observer B" as if distance from earth to sun, for instance, were not "objectively" 8+ light minutes... but rather "depends on the observational frame of reference." This is why, relativity can be called subjective idealism, with "subject" being frame of reference, however abstract.

Owl

 

A lot has been written about Einstein's debt to Ernst Mach, a positivist philosopher and physicist, in his development of relativity theory. What is real according to relativity theory depends on what can be measured: there is no distinction between what something is (its ontology) and how it is measured (operational positivism). So if time dilation can be measured only by the slowed mechanical action of clocks, then that is what time dilation is. There is no 'time' lying underneath 'time measurement' whose ontology-in-itself has to be determined -- since if there was, what would measure it?

I agree.... but for the variety of clocks which can be said to transcend "mechanical action." Still, if "Time is that which clocks measure"... This is a tautology which avoids the question, "What is time?" even tjhough it is still treated as an agent or entity along with space.

 

Owl

[ydoaPs]

The mathematical component IS the conceptual component; it's just a different(more accurate) language in which the concept is expressed.

[Marat]

I think some of the confusion arises from the fact that 'time' is a concept used informally in ordinary language, so it seems to be a 'something' independent of the operationalized processes which positivistically measure it for science. But for concepts which are only used within science, such as 'quantum entanglement,' we don't feel any obligation to account for their ontology per se, since it seems adequately fleshed out by its significance in the contexts in which it is used. Historically, mathematicians used to worry about the reality behind the numbers and the ontology behind the non-Euclidean geometries they were using, and if nothing could be pictured as corresponding to useful but 'artificial' numbers, they were suspect. Bolyai in his correspondence with Gauss discussed the problem of how the scientific public was going to react to non-Euclidean geometries which, while useful to mathematics, had no intuitive appeal since it was difficult if not impossible to specify their ontolgy or imagine what they look like.

 

In that context, I find your objecions to action at a distance interesting, since accepting the reality of this mechanical impossibility was an unavoidable implication of the fact that Newton's empiricially confirmed laws of motion for the planets indicated no retarding effect by the action of friction in the mechanism by which gravitational attraction was propagated. This forced him and his followers to assert gravitational action at a distance, which caused all the physicists of Europe, who felt that Cartesian mechanics with its particles-in-motion theories was the only thing that had saved physics from uselessly inventing magical properties, hidden virtues, and occult affinities to explain everything, to reject Newtonian action at a distance as an occult entity. One contemporary critic of Newton said gravitational action at a distance was no better as an explanatory hypothesis than the supposed ability of the knife used by a murderer to turn on a table and point to the murderer when he came into the room.

 

Eventually, however, physicists got sufficiently accumstomed to using it that this empty action over nothing seemed to have sufficient ontological status to be accepted. The general rule seems to be: Use, convenience, and context can provide sufficient ontological support on their own to satisfy the urge to say what a 'thing' is, even if no tangible picture can be conjured up to correspond to it. After all, what is the ontological picture of the square root of negative one?

[owl]

Just to be clear about my statement about gravitational "action at a distance":

 

(To put it simply, mass curving spacetime (as an abstract metric or as a substantive medium) is not the only explanation for how gravity works. The virtual particles of quantum mechanics is another, but this introduces the quandry of mystery called "action at a distance" for which there is no explanation.)

 

I accept that there is no explanation for how gravity works over distance way more easily than I can accept the metaphysical invention of the mystery medium spacetime as something that is curved by gravity and so "explains" the effect of gravity on objects. This is not to deny that the concept is a handy tool/model for relativity in its obviously improved ability to predict object movement. All that would be required is the honest labeling of the conceptual model "spacetime" as such, rather than the ubiquitous phrase "curved spacetime" as if "it" were actually something curved.I am not trying to "bring down relativity" as some have said elsewhere. And calling this an "ontology tangent," (Swansont) is quite unfair, though it seems to reflect the bias of this site. I am attempting to bring the discussion of spacetime ontology to these boards. It seems as if my intoduction of Ross's ontology of Non-Euclidean geometry and Deiks's comments on papers from the spacetime ontology conferences are being ignored.

 

YdoaPs's statement:

"The mathematical component IS the conceptual component; it's just a different(more accurate) language in which the concept is expressed."...

doesn't even address the ontology, the "what is happening in nature" part of Ross's statement:

 

"Just because the math works doesn't mean that we understand what is happening in nature. Every physical theory has a mathematical component and a conceptual component, but these two are often confused. Many speak as though the mathematical component confers understanding..."

 

With all due respect, I think the last sentence applies to you, ydoaPs.

 

And I think the same honesty-in-labeling applies to time, as I agreed with you above, Marat. Science would take a great leap toward such honesty if "time dilation" wre not constantly repeated designating time, at face value, as someting that dilates But it seems that the majority of relativity theorists have taken their textbooks at "face value" and actually do believe that time is somehting that changes in each and every different inertial environment... i.e., not just changes in the clocks.

Owl

Edited February 7, 2011 by owl

[ydoaPs]

YdoaPs's statement:

"The mathematical component IS the conceptual component; it's just a different(more accurate) language in which the concept is expressed."...

doesn't even address the ontology, the "what is happening in nature" part of Ross's statement:

 

"Just because the math works doesn't mean that we understand what is happening in nature. Every physical theory has a mathematical component and a conceptual component, but these two are often confused. Many speak as though the mathematical component confers understanding..."

 

With all due respect, I think the last sentence applies to you, ydoaPs..

 

So, he fails at Philosophy of Language; what's your point? The mathematics is how we know "what is happening in nature". Mathematics is the proper language with which to gain this information in that it is more specific and can be more easily compared to nature. Disregarding the mathematical explanation as being devoid of ontology is akin to claiming Ontology of Time is devoid of ontology because it is written in Russian. Mathematics does a far better job of giving us ontological truth in this case than does English. Through mathematics, we see that time acts exactly as distance does. In fact, they are so similar, we can extremely precisely treat them as one entity. Where do you think the Raisin Bread model came from?

[owl]

So, he fails at Philosophy of Language; what's your point? The mathematics is how we know "what is happening in nature". Mathematics is the proper language with which to gain this information in that it is more specific and can be more easily compared to nature. Disregarding the mathematical explanation as being devoid of ontology is akin to claiming Ontology of Time is devoid of ontology because it is written in Russian. Mathematics does a far better job of giving us ontological truth in this case than does English. Through mathematics, we see that time acts exactly as distance does. In fact, they are so similar, we can extremely precisely treat them as one entity. Where do you think the Raisin Bread model came from?

The raisin bread model, like the spacetime model, came out of someone's mind. The ontological question with any such model is "How well does the map fit the territory?" As a coordinate system we can locate whatever objects in space by their coodinates in a three axis system applied to any volume of space, and we can describe object movement with various vectors through time. We can also *conceptually expand the space* by devising a larger model/coordinate system and extend vector tracking through a longer period of time. Neither expansion is an "expansion of space or time" per se. The model is not the cosmos described by the model.

 

BTW, if we add a fouth axis to space it must be explained, as volume is already described by just three. And "extrinsic curvature relative to one manifold" vs "intrinsic curvature relative to another manifold" does not, by virtue of the language/concept make non-Euclidean "curvature of space" someting real in the cosmos... besides the model/concept, that is. Neither does saying that parallel lines intersect in some esoteric mathematical "infinity" make it so.... or that now that we have "curved space" (in our minds anyway) that the shortest distance between to points is no longer a straight line... curved as they now are in our non-Euclidean model.

[lemur]

The whole discussion of the ontology of space, time, and spacetime, is the collective effort to address these questions. I look forward to qualifying for such discussion in the appropriate context, philosophy of science, specifically the above ontology.

Time is the tendency for distinct clocks to remain synchronous. Time dilation theory predicts the extent to which different clocks will deviate from each other despite good mechanical functioning in divergent physical situations, such as different gravitational situations and/or levels of speed. I believe this correctly addresses the ontology of time and time dilation.

Edited February 15, 2011 by lemur

[owl]

Just a bump here, fishing for comments on my last post before I give up on the inquiry into the difference between "modeling" and the cosmos modeled... and that elusive fourth axis/dimension of space assumed by non-Euclideans as an essential part of relativity.

 

And I'm fine with "time" being left at event duration (between any two instants) as long as relativity doesn't insist on making an entity out of it, as the label "time dilation" implies. Just clocks ticking at different rates in different inertial environments... fine.

[sound]

time as we know it seems to go faster as we age

[lemur]

And I'm fine with "time" being left at event duration (between any two instants) as long as relativity doesn't insist on making an entity out of it, as the label "time dilation" implies. Just clocks ticking at different rates in different inertial environments... fine.

It's been a while since I've (attempted to) read Einstein on relativity, but I distinctly recall an easy-to-read section near the beginning explaining time very carefully in terms of simultaneous reading of different clocks. I agree that if you describe time as "dilating," it implies a thingness to it but this may be more metaphorical than concrete. Describing space/time as a "fabric" also objectifies it, but in a way I wonder if Einstein wasn't onto some kind of deconstruction by using objectifying language for these phenomena while at the same time relativizing them in a way that cause you to question their absoluteness. It's interesting to think about the ontology of time and space, but I don't think you can get many physicists too interested in worrying about it as a serious issue. Most people seem more concerned with the instrumental application of the concepts to accurately model observable phenomena.

[owl]

Leemur,

I agree with you about the language around "time." All relativity texts makes "it" into an entity in students mind, and then they "grow up to be" relativity theorists who weave "it" into the famous "fabric" spacetime with space also some kind of entity, rather than just the volume in which everything (masses and forces) exist and move. They all would have flunked their prep science classes in relativity without such acqiescence.

And nobody here wants to talk about the big transition, long ago, by which 3-D space somehow gained a fourth dimension and enough "entity-hood" to take shapes, expand, curve, etc. (From Euclid to "non.")

And "the model/metric" is not the territory the map describes. Do I repeat? Very well, I do repeat, hoping eventually for a direct answer without smoke and mirrors and "If you only understood the math..." kinds of answers... or "you just don't get relativity."

 

Look at how the sci-fi of "time travel" took on the pseudo-respectability of science. See latest post in that thread. So much for the past being gone (no longer present) and the future simply not present yet?

People will believe anything if repectable geniuses, like the architects of relativity endorse it. In fact you will be eventually "Boo-ed" out of any science forum if you challenge the ontological status of space, time, and spacetime.

 

I think that is enough from me on this soapbox... unless someone wants to explain that fourth spatial axis... or... what kind of a thing "time" is.

[owl]

We have been discussing the nature of time in the "Is Time Travel Possible" thread, and I recently posted a "reality check" there, contrasting clock time, with its undeniable variability (misnamed "time dilation" in the relativity community) with what a year (and its fractional divisions) means in "the real world," i.e., one earth orbit around sun.

So then how could an earth commensurate (based on the natural cycles) standardized version of "clock time" be established? Greenwich Mean Time is of course the longitudinal time line for "time zone" reference around the globe, but we must also consider altitude and latitude as variables effecting clocks.

So I propose that standardized elapsed time be based on clocks situated around the equator at sea level and synchronized with one of the three standard ways of measuring "the year" (sidereal, tropical, or anomalistic... We will need to pick one...) and all fractions thereof.

 

Then we can put an end to the relativistic claim that "all time is relative" to what frame of reference a given clock is "ticking" in, i.e., high or low gravity field, fast or slow velocity, etc.

Maybe, in the process, we can quit the ubiquitous reification of time that I have been bitching about... assuming that "it" is a variable entity. At least, recognizing time as an artifact of measurement of event duration, we would then have a global standard with which to compare all clock variations and get over "time dilation."

[foszae]

owl, can i ask a question? what do you want this standardized clock for?

 

i study theoretical physics; and if i wanted to be an asshole, i could take the relativity argument and run it to the ground, digging up even crazier, harder-to-quantify version of the mutabilitity of Time. frankly, Einstein's version of time dilation is a century old and while valid, is pretty much lightweight fluff compared to what Time looks like it could be. relativity is pretty last millenium from where i sit. mind you, i sit on the side where Time acts weirder than the standard model is ready to accept anyhow. (i get booed a lot)

 

i understand your definition of ontologically standardized time for everyone, and can conveniently forget the other stuff. but what are you trying to produce here? are you after an inerrant sense of seconds passing at the exact same rate all the time? what goal do you have here then?

[swansont]

We have been discussing the nature of time in the "Is Time Travel Possible" thread, and I recently posted a "reality check" there, contrasting clock time, with its undeniable variability (misnamed "time dilation" in the relativity community) with what a year (and its fractional divisions) means in "the real world," i.e., one earth orbit around sun.

So then how could an earth commensurate (based on the natural cycles) standardized version of "clock time" be established? Greenwich Mean Time is of course the longitudinal time line for "time zone" reference around the globe, but we must also consider altitude and latitude as variables effecting clocks.

So I propose that standardized elapsed time be based on clocks situated around the equator at sea level and synchronized with one of the three standard ways of measuring "the year" (sidereal, tropical, or anomalistic... We will need to pick one...) and all fractions thereof.

 

Then we can put an end to the relativistic claim that "all time is relative" to what frame of reference a given clock is "ticking" in, i.e., high or low gravity field, fast or slow velocity, etc.

Maybe, in the process, we can quit the ubiquitous reification of time that I have been bitching about... assuming that "it" is a variable entity. At least, recognizing time as an artifact of measurement of event duration, we would then have a global standard with which to compare all clock variations and get over "time dilation."

 

You're confusing politics with physics. Time zones/longitudinal variations and the desire to standardize these is for human convenience. It's not physics.

[Iggy]

We have been discussing the nature of time in the "Is Time Travel Possible" thread, and I recently posted a "reality check" there, contrasting clock time, with its undeniable variability (misnamed "time dilation" in the relativity community) with what a year (and its fractional divisions) means in "the real world," i.e., one earth orbit around sun.

An earth orbit is "clock time". The duration between events as measured by earth's orbit around the sun dilates just like any duration measured by any clock. The earth isn't special even if it occupies a very special place in your head.

 

So then how could an earth commensurate (based on the natural cycles) standardized version of "clock time" be established?

Every clock is based on cycles. Earth's cycles are not special even if you consider them "natural" -- whatever that means.

 

Greenwich Mean Time is of course the longitudinal time line for "time zone" reference around the globe, but we must also consider altitude and latitude as variables effecting clocks.

 

So I propose that standardized elapsed time be based on clocks situated around the equator at sea level and synchronized with one of the three standard ways of measuring "the year" (sidereal, tropical, or anomalistic... We will need to pick one...) and all fractions thereof.

 

Bad idea:

 

Although there are several different kinds of year (as there are several kinds of day), it is best to regard a year as a julian year of 365.25 days (31.5576 Ms) unless otherwise specified.

 

It should be noted that sidereal, solar and universal time are best regarded as measures of hour angle expressed in time measure; they can be used to identify instants of time, but they are not suitable for use as precise measures of intervals of time since the rate of rotation of Earth, on which they depend, is variable with respect to the SI second.

International Astronomical Union: SI Units

 

Then we can put an end to the relativistic claim that "all time is relative" to what frame of reference a given clock is "ticking" in, i.e., high or low gravity field, fast or slow velocity, etc... At least, recognizing time as an artifact of measurement of event duration, we would then have a global standard with which to compare all clock variations and get over "time dilation."

We would just have to be careful not to synchronize our clocks with "natural cycles" near cygnus x1, because then the human lifespan would only be a few seconds and I wouldn't mind living rather longer than that.

[owl]

owl, can i ask a question? what do you want this standardized clock for?

 

i study theoretical physics; and if i wanted to be an asshole, i could take the relativity argument and run it to the ground, digging up even crazier, harder-to-quantify version of the mutabilitity of Time. frankly, Einstein's version of time dilation is a century old and while valid, is pretty much lightweight fluff compared to what Time looks like it could be. relativity is pretty last millenium from where i sit. mind you, i sit on the side where Time acts weirder than the standard model is ready to accept anyhow. (i get booed a lot)

 

i understand your definition of ontologically standardized time for everyone, and can conveniently forget the other stuff. but what are you trying to produce here? are you after an inerrant sense of seconds passing at the exact same rate all the time? what goal do you have here then?

 

I came to this thread again to clarify my reply to a thought experiment by I ME in the "Time Travel--Impossible" thread... his post #66 and my reply in 67. Hopefully this reply will also be relevant to swansont's objection:

You're confusing politics with physics. Time zones/longitudinal variations and the desire to standardize these is for human convenience. It's not physics.

I ME wrote:

Say you leave in the year 2020. Per your rocket calendar, when you arrive back on Earth it is the year 2025. But calendars on Earth say it is the year 2030. So you arrive back on Earth 5 years into the future!

I replied;

What could the last statement possibly mean? You come back to an Earth in which events have not yet happened and will not happen for five more years? Does this make any sense at all? Not to me!

So, to sort it out and provide a 'reality check' on what an actual year is see my post here on 5/26.

 

We have an earth-commensurate measure of distance in the meter, which is (if I remember correctly) one ten-millionth of the surface distance from equator to pole. I thought that rather than saying that time is all relative to clocks' variable rates of 'ticking' at different velocities and gravity levels (and space rocket clocks/calendars being just as valid as observed earth orbits for "year" reckoning)... that a standardized year (one of the three) should become the earth-commensurate year standard... and divisions thereof.

Also, our most accurate clocks situated at sea level would standardize the altitude/gravity factor, and on the equator would standardize the latitude/velocity factor.

 

Then, when a rocket goes on a near-light-speed round trip and comes back with only five years elapsed on its clock/calendar while ten years have elapsed on earth, the 'reality check" is that, in fact, there have been ten earth orbits (actual years elapsed), monitored by the above synchronized, standardized earth-based clocks. So the rocket's time keeping error will be obvious, and the absurdity of arriving back five years in earth's future will be clearly debunked... along with "time dilation."

Philosophically, all of the above is an argument against the relativity dictum "everything is relative"... and a "reality base"of empirical observation" (a precise measure of an earth orbit) for that argument.

[mpc755]

Swansont wrote:

"Clocks "tick" at different rates in different inertial circumstances, as proven by many experiments. does not specifically address the issue of whether it's a mechanical issue of the clock. But this issue has not been ignored — different types of clocks have been tested, and they all show the time dilation effect. So we conclude that the timing changes are due to the effects of relativity. "

 

I'm trying to get at the ontolology of "time," like, what is "it" besides event duration between designated instants?

I know that our most sophistcated clocks show what has come to be known as "time dilation," but how is that different than, as above, the fact that they "keep time" differently (slow down or speed up) in different inertial environment

 

Clocks keeping time at different rates is a different issue than asserting that "time itself" is an actual medium/entity which differes in each and every local inertia situation.

I hope I'm making this distinction clearly. The ontology of time is a deep subject and relativity does not have a lock on time as a malleable medium in an of "itself," which clocks simply measure.

 

Even the debate about a "global time structure" shed light on the assumption of relativity that local inertial frames of reference are the end all of the nature of time, space and the universe.

BTW, I am not advocating that time is a "structure" but more like this: It is now everywhere (ongoing, perpetually), and time is an artifact of measurement, i.e., the duration of a given event between two designated instants.

 

What say you?

Respectfully,

Owl

An astronomer and an astronaut are in a spaceship traveling very fast around the Earth and the astronomer determines one year has passed based on the position of the Earth with respect to the Sun based on the distant stars then why is the atomic clock which has not yet clocked one years worth of ticks considered to be more accurate when in actuality it isn't? If there are a million people on the spaceship and they all determine one year has passed based upon the location of the Earth with respect to the Sun based upon the distant stars and one person insists one year has not yet passed because the atomic clock has not clocked a years worth of ticks who is correct?

 

All that has to occur to correct the notion of time is to define a second correctly. The present definition is:

 

http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html

 

"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom."

 

The more correct definition is:

 

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom at sea level.

 

Since the astronaut knows they are not at sea level they will correct the rate at which their atomic clock ticks accordingly and after one year be in agreement with the other one million people on the spaceship that one year has passed.

Edited May 28, 2011 by mpc755

[swansont]

The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom at sea level.

 

Since the astronaut knows they are not at sea level they will correct the rate at which their atomic clock ticks accordingly and after one year be in agreement with the other one million people on the spaceship that one year has passed.

 

The reason for the discrepancy of the spaceship clock and the earth clock is not that the spaceship clock is not at sea level. One can determine who is right in this instance because one set of observers is accelerating, and you can tell that they are not in an inertial frame.

 

We have an earth-commensurate measure of distance in the meter, which is (if I remember correctly) one ten-millionth of the surface distance from equator to pole. I thought that rather than saying that time is all relative to clocks' variable rates of 'ticking' at different velocities and gravity levels (and space rocket clocks/calendars being just as valid as observed earth orbits for "year" reckoning)... that a standardized year (one of the three) should become the earth-commensurate year standard... and divisions thereof.

Also, our most accurate clocks situated at sea level would standardize the altitude/gravity factor, and on the equator would standardize the latitude/velocity factor.

 

Then, when a rocket goes on a near-light-speed round trip and comes back with only five years elapsed on its clock/calendar while ten years have elapsed on earth, the 'reality check" is that, in fact, there have been ten earth orbits (actual years elapsed), monitored by the above synchronized, standardized earth-based clocks. So the rocket's time keeping error will be obvious, and the absurdity of arriving back five years in earth's future will be clearly debunked... along with "time dilation."

Philosophically, all of the above is an argument against the relativity dictum "everything is relative"... and a "reality base"of empirical observation" (a precise measure of an earth orbit) for that argument.

 

Until the spaceship accelerates, that the rocket's timekeeping discrepancy is due to the rocket will not be obvious. A signal from the rocket to the earth and earth to rocket will show symmetric time dilation effects.