Danshawen has a real issue with Brian Greene. Does he make sense when he discusses his issue with the way Greene is conveying physics verbally to the unititiated like danshawen. No. I'm still waiting for any crank, much less danshawen, to actually make sense with respect to modern physics. They seem to relish their ignorance of anything they didn't thunk up.
The Illusion Of Time - The Fabric Of The Cosmos
- Thread starter prometheus007
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Correct. So, as I said, you are in agreement with the Lorentz transformation on this small point. Now what did Brian Greene illustrate? The alien traveling at a receding vs. approaching relative velocity? Find the timestamp of the video where you are in disagreement with him.
No, I have confidence that the experimental evidence shows that the relationship between two frames of reference goes as the projection of a rotation onto an observation plane. You seem to have confidence that this is not the case. But you are trumped by all experimental data. Further, I have confidence that you did not understand what I just wrote. Further, I am quite confident that just about every 1st or 2nd year math or science student knows exactly what I just said.
And yes, I am quite convinced that trig is an essential statement of the mathematical laws needed to state what a projection of a rotation actually is.
That much is not evident in your writing.
Your belief here is confronted by all experimental data.
Ok so your issue is more fundamental than Linear Algebra. You don't understand freshman kinematics. No such restriction applies in the use of reference frames. They can be nailed to walls, floors, ceilings, or actual nails. It matters not. Here you lack common experience with coordinate systems, which is high school level stuff.
You are confusing the experimental data (real world behavior) with the resulting explanations that follow them. You are claiming that nothing can be stated quantitatively in science using the appropriate language of mathematics as applicable to the problem at hand. Since the observed phenomenon is a projection of a rotation then that's the mathematical language which applies.
Here you are missing the point: the applicable language for this explanation is the projection of a rotation upon an observation plane which is better characterized as as topic of Linear Algebra, which most people take after calculus, and calculus is usually a couple of courses after trig. In any case, your mastery of something or how it compares to my training is moot. The question amounts to understanding Fitzeau et al., which requires physics, and by that I mean you have to be able to at least understand what they discovered, if not to be able to explain it correctly yourself.
The reverse is true. You seem to have swallowed a bunch of assumptions about the above mentioned experimental data, which are invalid.
I did nothing. I took the courses, read some of the applicable papers, and discovered where the science came from. You should do the same.
The laws arising from the data correctly state that the phenomenon in relativity follows the effect of projecting a rotation onto an observation plane. Start there and there is nothing to assume, no one to accuse of being gullible. But at least strive to be correct in your assessments here.
Feel free to correct any errors I have committed here by bringing us your own reformulation of modern physics.
In Australia we call it the "tall poppy syndrome"....and add a touch of delusions of grandeur about one's self, and voila! we have "the god" rajesh and Farsight!
danshawen
Valued Senior Member
The only reason that anything connected to the concept space of works at all is because of the simple relationships between space and light travel time, space and energy Doppler shifts. The invariance of the speed of light depends on the invariance of the instant of 'NOW' in every inertial reference frame, and does not depend on a fixed coordinate for space at all. There is no origin of space from which to build a Lorentz coordinate system. There is no such thing as an interval of space (length) that is fixed in any reference frame.
Let's finally put Minkowski "rotation" of lengths into time dilations to rest.
Posit a cube that occupies a volume of 1 cubic meter in the rest frame. Each vertex of said solid cube is fitted with a three axis laser apparatus so that propagating laser beams define each edge of the cube and are reflected back along the edge as if each edge of the cube were a laser cavity. In addition, beacons are attached to every vertex is visible on approach as well.
An impulse accelerates the cube to relativistic speed and a high speed camera is placed in the path of the cube, dead center to one of the approaching laser traced faces of the cube. Describe the Minkowski rotation of the faces AND the modified paths of the light beams defining the edges just before the camera collides with the center of one of the approaching cubic faces.
Those light beams would have to be bent, wouldn't they? But the cube isn't accelerating; it's traveling at a constant velocity. So, there is not-too-subtle a contradiction about Minkowski rotation here. None of the laser beams skirting the edges of the cube are allowed to be bent in such a way that the speed of light fails to be invariant, yet a relativistic cube face traveling at constant relativistic speed appears to be deformed.
Go ahead; use your trigonometry or even hyperbolic trigonometry to show me why this thought experiment is in error.
There is no Minkowski rotation. Intervals are neither Pythagorean-complex nor invariant. Only the speed of light and the instant (not interval) of 'NOW' is invariant in relativistic space.
Hint to obtain the result I did: In Mimkowski spacetime, "simultaneous" events that are further away occur first. The flashing beacons at the cube vertices are synchronous in the rest frame.
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I'm pretty sure that the mastery of trigonometry and calculus is a load of bullshit. He excels at making claims that he can't back up with any type of analysis. Mathematical physics. LOL. His hypothesis is the Higgs mechanism is the source of gravity. He recently claimed his hypothesis is getting serious consideration. Including from Matt Strassler. Goofy crank.
Why bring in Nationalistic fervor? The Board has an international appeal and you are soiling the very nature of the same by bringing in such point in the thick of the argument. I am not inclined to belive that James R and Brucep are handling you with kiddy gloves, just because you are an Australian. Poor taste and bad looser.
Are you serious??
.Perhaps its you that's being treated with kid gloves, as most seem aware of who you probably were and the reasons for your tantrums.
You seem to stupidly ignore the fact that the measurement of time takes on two concepts: [1] the time deduced from periodic motions of our close celestial neighbours [Earth/Moon/Sun]
A day, month and year are based on these motions and have been since time immemorable.
These units are variable due to periodic variations in the movements of planetary bodies, but are strictly adhered to, defined and adjusted accordingly.
[2] For sake of convenience, other units of time, such as second minute and hour were devised in Babylonian/Egyptian time.
The second was then accurately defined and based on the caesium atom as a base unit of time and fixed.
Those are the facts. It's as simple as that.
It has. If two spacecrafts (frames) are moving at a speed of around 0.1c with respect to Earth, then will you be able to calculate the time dilation between the two frames on the spacecrafts? Try and let me know.
This is the matter of interpretation of definition of what you call "Time Travel"..... There are certain issues with what you are suggesting as 'time travel'..
a. Time Dilation requires two frames, comparison of lapse time in both the frames.
b. If the travelling Twin starts her journey on 20th Sep 2015, then 'Travel to Past" would mean travel to something like 19th Sep 2015 or earlier in the self frame.
c. Similarly if the travelling twin starts her journey on 20th Sep 2015, then "Travel to future" would mean travel to 21st Sep 2015 in self frame before others have reached there.
d. What you are trying to say, that a twin starting on 20th Sep 2015, if returns on sometime in 2017 with a time dilation of one day, then magically even in 2017, she is in past by one day and other sedentary people are in future by one day (Amount of time dilation). I have no dispute with the "Time Dilation" between the two frames, but terming this as Travel to Past or future is playing with the words.
I think popularly, what I have written in (b) and (c) is understood as "time travel", but if you have anything to support your version, you may define.
I suggest it is you playing, as I have told you previously. Most experts obviously see it as time travel and just as obviously that's what it is.
My example in the extreme.
two twins: one leaves at 99.999% "c" travels for 6 months, turns around and arrives back on Earth 12 months later from the day he left, according to his own biological and mechanical clocks.
He steps out of his ship, finds his twin long dead and buried, and an Earth approximately 235 years in the future.
Future time travel in anyone's language.
In my Post # 148 (b) and (c), I have defined what the popular understanding of the time travel is. This definition of 'Time Travel' may be incorrect, so before you jump to argument which will surely lead to what not, I request you to please define the time travel first, and then examples etc can flow. Not a great thing to ask?
Your popular idea of time travel and your other alternative ideas do not interest me and are wrong. Time dilation will lead to time travel as per the example I gave.Aid has already informed you of that in no uncertain terms.
I'm also not too interested in your requests either. rajesh also had that "demand" attitude about him.
Schmelzer
Valued Senior Member
Not very reasonable. They can meet each other, talk with each other, if they are at the same place at the same Earth time. So, once they can do this, they conclude that they live at the same time.
So, "time dilation" is identified as a distortion of their clocks, inclusive their biological clocks, which has nothing to do with time. In this situation, they cannot tell which clocks are wrong, in fact they all may be wrong. But the fact that they all fail to work as clocks (for this, the clocks would have to measure time, that means, if synchronized initially, they would have to remain synchronized forever) is obvious. [/QUOTE]
danshawen
Valued Senior Member
It is clear that most here and elsewhere don't really "get" relativity's greatest lesson.
Let me spell it out for you:
(Unbound energy / bound energy) = c^2
Think of space in terms of light travel time, not a ratio of length (whatever that is) divided by time. BOTH are time, and this holds as well for 3 "spatial" dimensions as it does for one. There is only energy and time in this equation.
Euclidean / Pytagorean space plays with relationships which only exist in the context of geometric solids. Relativistic space doesn't work that way. The bound energy that is matter is MOSTLY comprised of empty "space", which is to say, "light travel time". There is no space. There is only time. The reason it appears to be "space" to you is that you are composed of a combination of bound an unbound energy. Go back and look at that equation again.
Try to forget about Ancient Greece. Aristotle, Archimedes, Euclid and Pythagorus. They are long dead. Geometric solids are composed of solid time and a lot of bound energy with a lot of empty light travel time between the bound energy particles Democratus called "atoms".
Einstein knew this. Minkowski did not. Special relativity is pure. General relativity is corrupted. The field equations in General Relativity use the geometric constant Pi, which is not constant, but relative to a state of rotation in relativistic space, which is the only space that exists outide of the mind of a mathematician.
Time does not need to be related to space geometrically. Time IS space. Neither energy nor bound energy may exceed the speed of light, but entanglement does this all the time. Not by going faster than light in a vacuum; by being at rest relative to propagating unbound energy.
Let me spell it out for you:
(Unbound energy / bound energy) = c^2
Think of space in terms of light travel time, not a ratio of length (whatever that is) divided by time. BOTH are time, and this holds as well for 3 "spatial" dimensions as it does for one. There is only energy and time in this equation.
Euclidean / Pytagorean space plays with relationships which only exist in the context of geometric solids. Relativistic space doesn't work that way. The bound energy that is matter is MOSTLY comprised of empty "space", which is to say, "light travel time". There is no space. There is only time. The reason it appears to be "space" to you is that you are composed of a combination of bound an unbound energy. Go back and look at that equation again.
Try to forget about Ancient Greece. Aristotle, Archimedes, Euclid and Pythagorus. They are long dead. Geometric solids are composed of solid time and a lot of bound energy with a lot of empty light travel time between the bound energy particles Democratus called "atoms".
Einstein knew this. Minkowski did not. Special relativity is pure. General relativity is corrupted. The field equations in General Relativity use the geometric constant Pi, which is not constant, but relative to a state of rotation in relativistic space, which is the only space that exists outide of the mind of a mathematician.
Time does not need to be related to space geometrically. Time IS space. Neither energy nor bound energy may exceed the speed of light, but entanglement does this all the time. Not by going faster than light in a vacuum; by being at rest relative to propagating unbound energy.
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This equation has some issues. Units on both the sides are different.
Yes, since the returning twin has jumped into the future, she is living "at the same time" as her older twin. And yet (a little harder to fathom) the older twin, upon seeing that the traveling sister is younger than her, may experience "jumping to the past", a notion that confronts her whenever they are together. In an extreme example, a dinosaur that had been taken by near lightspeed star trekking aliens, then returned a moment later (on their clocks) would give the modern observers studying it the sense that they were existing in two eras simultaneously.
I wouldn't cast it that way at all. I would simply say that the amount of time elapsed in the two frames did not agree because the rates changed when one frame diverged from the other due to relative velocity.
It has everything to do with time, insofar as it demonstrates that the rate time elapses is only meaningful within the context of a chosen reference frame. Other than that, I am not sure what you mean.
No, they are both right. That's the paradox. Or you can say that's the consequence of time dilation due to relative motion.
No, the clocks continually mark time within their respective frames.
It is only obvious, i.e. your statement is only true, if the clocks remain forever in the same reference frame. That is not possible here since there is relative motion involved.
You seem to think time is absolute, which is impossible. There are an infinity of such "absolutes", one for each relative velocity achievable. And there are an infinity of such velocities to choose from, even within some small amount of relative acceleration.
I would think The God would have better spelling skills than this.
Schmelzer
Valued Senior Member
Simply ask yourself about the purpose of measuring time. Last but not least, people have cared about measuring time long before they have cared to measure, say, pressure. There are quite obvious pragmatical reasons to measure time - coordination. We want to to organize a meeting. How to do this? Very simple, we define a place where we meet. Here we don't have to measure anything else, a place is a place, some general characteristics of this place are sufficient to identify the place. But we also have to identify the time. If we come at different times to the place of the meeting, the meeting fails. But, different from places, general characteristics like "when it starts to rain" are not really sufficient. Ok, one can use days, but this is not accurate enough. To have a measurement of time would be helpful.
So, clocks are what we need to organize such a meeting. The ideal clock has the following simple property: If I have such a clock, and you have such a clock, and we synchronize them now, they remain synchronized forever. In this case, it would be easy to organize the next meeting: We meet when our clocks show time XX:xx.
Of course, inaccurate clocks will fail to do this job. And there is a simple way to find out inaccurate clocks: Use two of them and compare if they remain synchronized or not. This is in agreement with a quite general idea about how to identify the accuracy of our most accurate measurement devices (those where we cannot use more accurate devices to measure their error, simply because we don't have them): Compare the measurement results of different devices if they measure the same thing. So, if two of our best clocks show 1 sec. difference if we compare them one day after exact synchronization, we have an information about their accuracy.
Similarly, the same technique can be used to evaluate what distorts our measurement devices. So, if measuring the same thing A gives result X at temperature t1 and result Y at temperature t2, and |X-Y| is much greater than the differences we obtain if above measurement are made at the same temperature, we can be quite sure that temperature distorts or our measurements.
Following this scheme, we can easily establish that clocks do not measure time really accurate, and that their error depends on their velocity and the gravitational of their location.
If you like mystics and paradoxes, you can, of course, interpret inaccurate clocks as distortions of time itself.
No, this is the definition what it means to have an accurate, ideal clock. So you can reformulate this as the claim that no ideal clocks exist. This, of course, would not be nice. But it would not be a sufficient reason to change the definition of of an ideal clock.
It is not impossible. At least, we don't have any serious evidence that it is. All what we know is that we do not have, yet, local clocks able to measure it.
A natural candidate exists: Time after the BB, as measured by a clock at rest relative to CMBR.
So what? That means only that there is an infinity of candidates we are not able to exclude based on the actual theory of fundamental physics. This could be a point if we would know that our actual theory is the true fundamental theory of everything. We don't. Instead, we have several theories, and these theories are in contradiction with each other.
No, because you have not stated the information necessary to calculate a relativistic scenario: (1) choice of reference frame, and (2) relative speed between reference frame and observed frame.
I think that was Brian Greene's definition. We should probably get back to what he said.
Agreed, which is why I objected to what you said immediately above.
Or later. But that's not what Brian Greens is describing. He is explaining relativity.
Or sooner. And same for relativity.
Then why not just get back to what Brian Greene actually said, and lets talk about what a genius he is and how awesome this video is.
I am merely trying my best to get the conversation back to the subject matter at hand.
Just don't waken The Angry God. Personally, I'd to wake the God of R&R and have her zap some of these folks into Timeout (speaking of time, that is).
I have. Conclusion: time is relative.
The oldest document I know of involved counting (listing) the earliest kings of Sumeria. Oldest writings usually involved counting livestock and agricultural output.
That's impossible unless you add the stipulation that they are forever kept in the same reference frame.
That's not even an issue. Accuracy of clocks is moot; time is relative therefore the returning twin returns younger, and her clock establishes her actual age, despite the date of her return and the time elapsed on Earth since her birth.
You are addressing something different. The subject here is relativity. (More specifically: the fabric of the cosmos.)
Sounds like subject matter for a thread on instrument calibration.
You seem to want to talk about instrumentation. And yes, temperature affects most kinds of measurements.
No, that would not necessarily be properly called error. Nor does it necessarily have anything to do with measurement accuracy. Clocks measure time within their own reference frame. Time is relative, so only clocks left undisturbed within a common reference frame can be expected to perform as well as designed.
I like cosmology, the subject here. And it's full of rich technical language. The appropriate term here is time dilation. And the correct concept involves the change in the rate time elapses in a remote frame, as seen by a local observer. That change is described best as a projection of a rotation of remote spacetime onto the observation plane (spacetime). Brian Greene has taken this subject deeper, into the concept of a spacetime fabric, still unadressed in much of the content of this thread.
The subject here is not clock technology, nor is it really necessary to go very far into that. Einstein's explanation arose from his familiarity with his father's problems trying to synchronize clocks at two train stations. And that deals with the limits of accuracy at the end of the 19th c.
Your scenario is impossible to the extent that you are ignoring relativity, which is a real physical phenomenon.
That's immaterial. My point was that there are an infinite number of time slices between any two points in time. And that criteria is pretty weird, since we can't establish the moment of the initial expansion with any useful accuracy.
No, in the case of (special) relativity we have one theory (explanation) of the observations from ca. 1850-1905 in all labs in the world reporting speed of light measurements. And that explanation, in its initial form, appears in Einstein's 1905 paper: special relativity.
I keep saying "projection of a rotation" thinking this best characterizes the Lorentz transformation. Anyone who masters calculus probably already mastered trig, and by that time they either already encountered coordinate rotation, or will see it withing a semester or two, so it sounded pretty overblown to me.
The low point, I thought, was taking issue with the use of coordinate systems ("can't nail an origin to a point in space.")
Sounds like code for "God created the universe" insofar as it was (in this case: unfortunately) called "the God particle")
No doubt. Even the best folks here tend to give ideas serious consideration before dismissing them as junk science.
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