ISF Logo   IS Forum
Forum Index Register Members List Events Mark Forums Read Help

Go Back   International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology
 


Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
Reply
Old 27th October 2020, 10:03 PM   #1081
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
Your diagram assumes different acceleration between the back and the front.
I am talking about different setup, where the acceleration is the same.
The back and the front clock would have the same light propagation, not like yours.
It is exactly the same as the diagram you claim proves your case, I just zoomed in on a part.

So are you now saying that the diagram you have been using for the past couple of pages is flawed???

Do you agree that light must follow the null geodesics?

Just sketch in for me how the light clock at the front can have the same number of ticks as the light clock at the back and still follow the null geodesics.

You can do it on the diagram you have been using if you like.

__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th October 2020, 10:15 PM   #1082
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Robin View Post
The picture for this does not appear to be showing. Here is why the dx at the front can't be the same as the dx for the back for the same dt for an accelerated rigid object. Incidentally, if this was transformed to Rindler coordinates, the lines would diverge:


Only if the acceleration goes to infinity. That's unrealistic. There is a mass increase with the acceleration, ...
The front spaceship worldline has to become a photon world line, the null geodesic.
Only then the back light is not going to catch the front.
The Rindler horizon is mathematical black hole with infinite radius.
Unrealistic.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th October 2020, 10:20 PM   #1083
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Robin View Post
It is exactly the same as the diagram you claim proves your case, I just zoomed in on a part.

So are you now saying that the diagram you have been using for the past couple of pages is flawed???

Do you agree that light must follow the null geodesics?

Just sketch in for me how the light clock at the front can have the same number of ticks as the light clock at the back and still follow the null geodesics.

You can do it on the diagram you have been using if you like.

https://robinsrevision.files.wordpre...e-10.png?w=553
I am saying this:



Because the acceleration is the same at the back and at the front.
This is in line with your own table:
 
PI Rindler Coordinates
x* t* x t
M1 1.7183 0 1.718 0
M2 9.2267 9.859 1.718 2
A1 0.5431 -1.175 0 -1
A2 0.5431 1.175 0 1

Last edited by SDG; 27th October 2020 at 10:22 PM.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th October 2020, 10:31 PM   #1084
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
I am saying this:

That does not seem to require comment.
Quote:
Because the acceleration is the same at the back and at the front.
This is in line with your own table:
 
PI Rindler Coordinates
x* t* x t
M1 1.7183 0 1.718 0
M2 9.2267 9.859 1.718 2
A1 0.5431 -1.175 0 -1
A2 0.5431 1.175 0 1
Nope, those figures are based on the Rindler transformations and therefore assume the acceleration is different front and back
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th October 2020, 10:47 PM   #1085
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
The point is, if you are talking about some situation where the front and the back of a rigid body can accelerate at the same rate and for it not to get any longer and for light from the back still to reach the front even as it gets close to the speed of light then you are not talking about relativity any more.

You are basically just talking about some private theory of your own.
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 27th October 2020, 11:35 PM   #1086
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
Only if the acceleration goes to infinity.
I see. So basically you are saying that it stops accelerating at some point to allow the light from A2 to catch up.

At what point does it stop accelerating?

Because if the front observer is accelerating at the same rate as the back observer then as long as the acceleration continues the light from A2 will not catch up to the front.
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 04:42 AM   #1087
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
Your diagram assumes different acceleration between the back and the front.
That is required for them to be comoving.

Quote:
I am talking about different setup, where the acceleration is the same.
Then they cannot both be stationary in Rindler coordinates. Either way, you are still wrong. As always.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 04:45 AM   #1088
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
I am saying this:
That is pure nonsense. You have pasted together two different coordinates which will not even match at the boundary. That will produce errors.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 08:30 AM   #1089
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Robin View Post
I see. So basically you are saying that it stops accelerating at some point to allow the light from A2 to catch up.

At what point does it stop accelerating?

Because if the front observer is accelerating at the same rate as the back observer then as long as the acceleration continues the light from A2 will not catch up to the front.
The light propagation has a limit, speed of light!
The acceleration does not have a limit!!
Wooow, what a brilliant idea!!!!

This is really a bad joke.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 08:45 AM   #1090
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
The light propagation has a limit, speed of light!
The acceleration does not have a limit!!
Wooow, what a brilliant idea!!!!

This is really a bad joke.
At x=1, the function y=1/x is decreasing. As x increases, does y ever stop decreasing? Does y have a lower limit? At what value of x does y reach that lower limit?

You suck at math. And you will never understand a math-heavy theory because you suck at it. I really can't overstate how much you suck at math. It needs to be said again and again and again, and it still probably won't be enough.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 08:51 AM   #1091
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
That is required for them to be comoving.



Then they cannot both be stationary in Rindler coordinates. Either way, you are still wrong. As always.
Sooo???
That's what I am saying. The Rindler horizon is a 'mathematical black hole' with infinite radius.
How can an infinite radius have different acceleration for a 100m radius delta?
The problem is the Rindler horizon was conceived with an unlimited duration of the acceleration.
This is the logical flaw.
Why you do not defend logic behind the Rindler horizon?

For example the Rindler horizon says the l0 is not changing.
Is the length contraction real or not?

https://en.wikipedia.org/wiki/Bell%2...ceship_paradox

Quote:
Bell's spaceship paradox is a thought experiment in special relativity. It was designed by E. Dewan and M. Beran in 1959[1] and became more widely known when J. S. Bell included a modified version.[2] A delicate string or thread hangs between two spaceships. Both spaceships start accelerating simultaneously and equally as measured in the inertial frame S, thus having the same velocity at all times in S. Therefore, they are all subject to the same Lorentz contraction, so the entire assembly seems to be equally contracted in the S frame with respect to the length at the start. Therefore, at first sight, it might appear that the thread will not break during acceleration.

This argument, however, is incorrect as shown by Dewan and Beran and Bell.[1][2] The distance between the spaceships does not undergo Lorentz contraction with respect to the distance at the start, because in S, it is effectively defined to remain the same, due to the equal and simultaneous acceleration of both spaceships in S. It also turns out that the rest length between the two has increased in the frames in which they are momentarily at rest (S′), because the accelerations of the spaceships are not simultaneous here due to relativity of simultaneity. The thread, on the other hand, being a physical object held together by electrostatic forces, maintains the same rest length. Thus, in frame S, it must be Lorentz contracted, which result can also be derived when the electromagnetic fields of bodies in motion are considered. So, calculations made in both frames show that the thread will break; in S′ due to the non-simultaneous acceleration and the increasing distance between the spaceships, and in S due to length contraction of the thread.

In the following, the rest length[3] or proper length[4] of an object is its length measured in the object's rest frame. (This length corresponds to the proper distance between two events in the special case, when these events are measured simultaneously at the endpoints in the object's rest frame.[4])
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 09:00 AM   #1092
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
That is pure nonsense. You have pasted together two different coordinates which will not even match at the boundary. That will produce errors.
If we assume the length contraction is real why the spaceship would not shrink to the size of the light wavelength?
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 09:05 AM   #1093
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
At x=1, the function y=1/x is decreasing. As x increases, does y ever stop decreasing? Does y have a lower limit? At what value of x does y reach that lower limit?

You suck at math. And you will never understand a math-heavy theory because you suck at it. I really can't overstate how much you suck at math. It needs to be said again and again and again, and it still probably won't be enough.
I do not suck at math.
If we start with wrong assumptions then the math will lead us to wrong conclusions.
Why the light propagation has a limit?
Why the acceleration duration does not have a limit?

Last edited by SDG; Yesterday at 09:32 AM.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 11:14 AM   #1094
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
I do not suck at math.
And once again, you are wrong. You do suck at math, oh so very much. You have proven that repeatedly.

Quote:
If we start with wrong assumptions then the math will lead us to wrong conclusions.
Sure. But that's not what any of this is about. We aren't discussing why relativity gives predictions which are contradicted by experiment. That would be an example of starting with the wrong assumptions leading us to the wrong conclusions.

But we're just talking about what the theory itself says. And you can't get that right. Even if the theory is wrong, it still makes definite predictions, and you don't even understand what those predictions are. That's not the fault of math, that's not even the fault of any wrong assumptions built into the theory. That's purely your own incompetence.

Quote:
Why the light propagation has a limit?
Why the acceleration duration does not have a limit?
Why is there no lower limit to the equation y=1/x?

This is, in fact, the exact same question. Seriously, the graph of a constant proper acceleration is mathematically identical to a graph of the function y=1/x. The only difference is that in the common way of graphing them, they're rotated by 45 degrees relative to each other. Unlimited acceleration is the same as the function y=1/x not having a lower limit. The velocity will asymptotically approach c, it never reaches or exceeds c, just as y asymptotically approaches 0 but never reaches or goes below zero.

But you didn't know this because you suck at math. You totally do.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 11:17 AM   #1095
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
If we assume the length contraction is real why the spaceship would not shrink to the size of the light wavelength?
It would eventually, in a non-accelerating reference frame.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 11:24 AM   #1096
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
That's what I am saying. The Rindler horizon is a 'mathematical black hole' with infinite radius.
How can an infinite radius have different acceleration for a 100m radius delta?
I have no idea what the hell you're even trying to ask here. What's delta?

Quote:
The problem is the Rindler horizon was conceived with an unlimited duration of the acceleration.
This is the logical flaw.
That is neither a problem nor a flaw. It does mean that no physical observer will ever experience an actual Rindler horizon, but so what?

Quote:
Why you do not defend logic behind the Rindler horizon?
Because it needs no defending.

Quote:
For example the Rindler horizon says the l0 is not changing.
Is the length contraction real or not?
Yes, it's real. But it is also reference frame dependent.

If you take a long stick and measure its x dimension, then rotate it and measure its x dimension again, is the change in its x dimension real? Yes.

That is exactly what's happening with length contraction.

Quote:
It's not an actual paradox. All of this has been explained to you multiple times.

Maybe you're just not smart enough. Not everyone is. You can't teach a dog calculus, maybe you will just never understand. Perhaps it's time for you to accept that, rather than act like a dog that thinks its inability to understand calculus means that calculus is wrong.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 12:44 PM   #1097
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
The Rindler horizon is...
Just a few posts ago you denied point blank you were using Rindler coordinates, so how are you back to talking about the Rindler Horizon?
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:04 PM   #1098
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Exclamation SDG writes his usual idiocy and lies about the Rindler horizon

Originally Posted by SDG View Post
Sooo???
That's what I am saying. The Rindler horizon is a 'mathematical black hole' with infinite radius. ...
The Rindler horizon is mathematically different from a black hole. There is no singularity. A Rindler horizon appears when acceleration starts. A Rindler horizon changes when acceleration changes. A Rindler horizon vanishes when the acceleration stops.
A source that SDG persists in being ignorant about is The Rindler Horizon by Greg Egan.
Quote:
Of course, this is not the same as a black hole’s event horizon in two very important respects. Firstly, it’s always possible to stop the spaceship accelerating, so this horizon’s persistence is a matter of choice, not physical law. Secondly, there is nothing corresponding to a black hole’s singularity to do any actual damage to anything passing through the horizon.
The Rindler horizon is does not have his nonsense of an "infinite radius". The horizon is not in front of the observer. The horizon is not a disk behind the observer. The horizon will have an infinite extent. SDG is lying about Fig. 12.13 from his textbook where the horizon is a straight line!
A source that SDG persists in being ignorant about is Rindler coordinates which has the Rindler horizon as a plane.

SDG writes "How can an infinite radius have different acceleration for a 100m radius delta?" idiocy. A radius is a distance, not an acceleration. A "100m radius delta" fantasy when the spacecraft is 1.7 "Rindler units" long.

SDG lies with "The problem is the Rindler horizon was conceived with an unlimited duration of the acceleration" when the Rindler horizon exists when an observer is uniformly accelerating. That observer will have no horizon when they were not accelerating. That observer will not have a horizon if they stop accelerating. That observer will have a different horizon if they change their acceleration. The Rindler horizon for an acceleration only exists during the limited extent of that acceleration.
Even his textbook shows that this is a lie. SDG posted images of a section on a uniformly accelerating observer that do not say that they were always and will be always be accelerating with that acceleration.

SDG writes "For example the Rindler horizon says the l0 is not changing." idiocy. The Rindler horizon is not length contraction.
The length L0 does not change because it is the length of SDG's spacecraft according to the observers in the spacecraft. They are going at the same speed (for a rigid spacecraft). Anyone with a basic knowledge of special relativity knows that means there is no length contraction. It is an observer travelling at a different speed that will measure a length contraction.

SDG lies with "Is the length contraction real or not?" and a citation of the resolved Bell's spaceship paradox which is about 2 spacecraft connected by a string, not SDG's scenario of 2 observers in a single spacecraft.

Last edited by Reality Check; Yesterday at 01:21 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:05 PM   #1099
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
SDG

If you don't suck at maths then give me the parametric equation for the front of your spaceship and then tell me the coordinates of M2 in the plane PI and show how you worked them out.
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:36 PM   #1100
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
Originally Posted by SDG View Post
If we assume the length contraction is real why the spaceship would not shrink to the size of the light wavelength?
It would eventually, in a non-accelerating reference frame.
OK, at what point the accelerated spaceship is a 'bunch' of photons/wavelength?
What wavelength?
How do we keep accelerating photons?

Last edited by SDG; Yesterday at 01:37 PM.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:45 PM   #1101
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Robin View Post
Just a few posts ago you denied point blank you were using Rindler coordinates, so how are you back to talking about the Rindler Horizon?
I am not sure what you mean.
I said the Rindler horizon is a mathematical gymnastics concept, a black hole with infinite radius.
It was pages ago.
I showed the Rindler coordinates light roundtrip long time ago, ... and how the spaceship has constant l0.
This is a misunderstanding.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:49 PM   #1102
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
OK, at what point the accelerated spaceship is a 'bunch' of photons/wavelength?
Your question makes no sense.

Quote:
How do we keep accelerating photons?
Photons don't accelerate. They can red shift or blue shift, though.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 01:53 PM   #1103
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Originally Posted by Ziggurat View Post
That is neither a problem nor a flaw. It does mean that no physical observer will ever experience an actual Rindler horizon, but so what?
It is more that it would take some extraordinary engineering and patience for a physical observer to experience a Rindler horizon.
An example: Have 2 spacecraft accelerating so that the horizon is about 10 light years behind them (Myriad's example of 0.1 g ). They are exchanging signals. One slows, falls behind the horizon and the signals stop. The signals will also redshift as the slowing spacecraft approaches the horizon.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 02:03 PM   #1104
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
Your question makes no sense.



Photons don't accelerate. They can red shift or blue shift, though.
You said the length contraction is real.
That means the accelerating spaceship has to transform to photons, correct?
Your 1/x, it will shrink beyond the Planck length, right?
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 02:06 PM   #1105
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Myriad View Post
It might be worth pointing out that for any reasonable constant linear acceleration, the distance to the Rindler horizon is vast. For travelers at the (iconic in "realistic" SF colony ship scenarios) constant acceleration of 0.1g, the Rindler horizon is about ten light years distant. That means the spaceship in these graphs with the signals being sent back and forth between A and M would be about 17 light years long. That's really inconveniently large for any material object.

Accordingly, for a measly 100m long spaceship, the differences in clock rate between the nose and the tail would not be detectable even with atomic clocks unless the acceleration rate were at Star Trek levels. (Better hope the "inertial dampers" are working properly, and then take into account whatever effects those have on clocks.)

These mathematics of accelerating reference frames have no relevance to typical "twin paradox" scenarios, which do not require ridiculously long spaceships nor rapid accelerations, and in which only the traveling twin ever accelerates at all.
How can a travelling twin be shorter than a light wavelength (beyond the Planck length) if as per Ziggurat the length contraction is real?

Last edited by SDG; Yesterday at 02:08 PM.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 02:16 PM   #1106
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
You said the length contraction is real.
Yes.

Quote:
That means the accelerating spaceship has to transform to photons, correct?
No.

Quote:
Your 1/x, it will shrink beyond the Planck length, right?
If you accelerated enough, yes.

But that's not a concern for several reasons. First off, the Planck length has no special meaning in special relativity, so within the context of the theory itself, this is not a problem. Nothing special happens at this point.

Second, from a practical viewpoint, this is also not a problem, because we can't accelerate anything close to that fast. Even with our highest power particle accelerators, we cannot get even a single electron near the required speed.

Third, even supposing you had some magic engine which could get a spaceship up to that speed, it would disintegrate well before reaching that speed so you'd never get to test it. Why? You would blue shift the CMB from the forward direction so much that it would vaporize your spaceship like a giant laser beam.

Now, is it possible that special relativity is an incorrect theory, and that it will break down at this point? Yes, it's possible. Newtonian mechanics are very accurate at low speeds, but we know that if you go fast enough it becomes inaccurate. Maybe special relativity is the same. But even if that's the case, not only are we nowhere near to being able to demonstrate this, but it still says nothing about the internal consistency of special relativity. Newtonian mechanics is internally consistent despite being wrong. Even if special relativity turns out to be wrong, it will still be internally consistent.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 02:18 PM   #1107
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
How can a travelling twin be shorter than a light wavelength (beyond the Planck length) if as per Ziggurat the length contraction is real?
Why is that a problem?

You are already shorter than a light wavelength. Light comes in all sorts of different wavelengths.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 03:53 PM   #1108
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
It was pages ago.
The last time you showed that Rindler chart was on post #1044. That is only one page ago.

Then, when I used the same chart to demonstrate conclusively that the clock at the front must tick faster than the clock at the back you rapidly decided that you weren't using Rindler co-ordinates after all.

Let me quote the part:

Originally Posted by SDG
Your diagram assumes different acceleration between the back and the front.
I am talking about different setup, where the acceleration is the same.
Even though it was the same diagram you had just used to argue that time must pass the same at the front or back.
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 04:02 PM   #1109
Robin
Penultimate Amazing
 
Join Date: Apr 2004
Posts: 12,564
Originally Posted by SDG View Post
I do not suck at math.
Sure you don't
Originally Posted by SDG View Post
I am saying this:

I would love to see the mathematics behind a light beam jumping back in time.
__________________
The non-theoretical character of metaphysics would not be in itself a defect; all arts have this non-theoretical character without thereby losing their high value for personal as well as for social life. The danger lies in the deceptive character of metaphysics; it gives the illusion of knowledge without actually giving any knowledge. This is the reason why we reject it. - Rudolf Carnap "Philosophy and Logical Syntax"

Last edited by Robin; Yesterday at 04:04 PM.
Robin is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Yesterday, 06:15 PM   #1110
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Exclamation More lies and ignorance from SDG when he has a relativity textbook

Originally Posted by SDG View Post
How can a travelling twin be shorter than a light wavelength (beyond the Planck length) if as per Ziggurat the length contraction is real?
SDG lies about Ziggurat's post which was Your question makes no sense when SDG wrote "OK, at what point the accelerated spaceship is a 'bunch' of photons/wavelength?" nonsense when the spaceship is always a spaceship .
SDG followed up with "How do we keep accelerating photons?" nonsense when we do not accelerate any photons - it is an accelerating spacecraft !

Ziggurat stated basic relativity with It would eventually, in a non-accelerating reference frame.
Inertial (non-accelerating) observers measure that an object travelling at a speed relative to them have a length contraction. They will measure that an accelerating spaceship's length will continuously decrease. In special relativity, this will go on forever. In quantum mechanics, we do not know what happens when the spacecraft length gets to the scale of the Planck length.

Of course the question that was answered is abysmal ignorance from SDG: "If we assume the length contraction is real why the spaceship would not shrink to the size of the light wavelength?".
Length contraction is real because it is verified (indirectly) by experiments and by the fact that SR works.
There is no "the size of the light wavelength". This is the electromagnetic spectrum. Light has wavelengths (sizes, plural) ranging from picometres (gamma rays) to 100,000 km (radio waves).

SDG lies with the question in his post. The travelling twin's length does not change. It is measurements of the travelling twin's length by other observers that change as in his textbook and stated many times here.
The twin paradox has the travelling twin with a speed of 99.995% the speed of light, a Lorentz factor of 100. For any reasonably sized twin that is many, many orders of magnitude greater then the Planck length. If we increase the speed to get the twin smaller than a Planck length, it is possible for the simple reason that we increased the speed ! The Planck length is not a boundary that magically stops length contraction. The Planck length is a unit of length in the system of Planck units. Theoretically, it is the scale at which quantum gravitational effects are thought to appear. What happens there needs a working theory of quantum gravity that we do not have.

Last edited by Reality Check; Yesterday at 06:35 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 08:11 AM   #1111
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
Yes.



No.



If you accelerated enough, yes.

But that's not a concern for several reasons. First off, the Planck length has no special meaning in special relativity, so within the context of the theory itself, this is not a problem. Nothing special happens at this point.

Second, from a practical viewpoint, this is also not a problem, because we can't accelerate anything close to that fast. Even with our highest power particle accelerators, we cannot get even a single electron near the required speed.

Third, even supposing you had some magic engine which could get a spaceship up to that speed, it would disintegrate well before reaching that speed so you'd never get to test it. Why? You would blue shift the CMB from the forward direction so much that it would vaporize your spaceship like a giant laser beam.

Now, is it possible that special relativity is an incorrect theory, and that it will break down at this point? Yes, it's possible. Newtonian mechanics are very accurate at low speeds, but we know that if you go fast enough it becomes inaccurate. Maybe special relativity is the same. But even if that's the case, not only are we nowhere near to being able to demonstrate this, but it still says nothing about the internal consistency of special relativity. Newtonian mechanics is internally consistent despite being wrong. Even if special relativity turns out to be wrong, it will still be internally consistent.
Ziggurat, interesting point.
Please, tell me, does it follow from the Special Relativity that a spaceship cannot reach and travel, let say at 0.7c or 0.866c, because the spaceship would be getting close to vaporizing?
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 08:21 AM   #1112
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
Ziggurat, interesting point.
Please, tell me, does it follow from the Special Relativity that a spaceship cannot reach and travel, let say at 0.7c or 0.866c, because the spaceship would be getting close to vaporizing?
No. That's a stupid question, and you should feel bad for asking it.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 08:39 AM   #1113
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
Why is that a problem?

You are already shorter than a light wavelength. Light comes in all sorts of different wavelengths.
The bold part?
So, gamma rays should not hurt me?
...and there are waves that have the whole visible universe wavelength.
I know there are long radio waves and we are shorter than those.

Seriously, though:
http://www.pitt.edu/~jdnorton/papers/Chasing.pdf

Quote:
...a paradox upon which I had already hit at the age of sixteen: If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as an electromagnetic field at rest though spatially oscillating.
This does not make sense.
There is no mass, photons are massless particles, no observer (observer has mass) can be observing any oscillation.
There is no time, no oscillation.
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 08:49 AM   #1114
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
No. That's a stupid question, and you should feel bad for asking it.
No, this is not a stupid question.
What happens when a spaceship travels at 0.866c and there is a transverse electric wave (polarized light) going across the spaceship?
How is it observed from the outside frame?
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 08:56 AM   #1115
Ziggurat
Penultimate Amazing
 
Ziggurat's Avatar
 
Join Date: Jun 2003
Posts: 47,300
Originally Posted by SDG View Post
The bold part?
So, gamma rays should not hurt me?
Stop asking stupid questions.

Quote:
This does not make sense.
There is no mass, photons are massless particles, no observer (observer has mass) can be observing any oscillation.
There is no time, no oscillation.
You missed the entire point, which was that Einstein was asking this in the context of Newtonian physics, since this was PRIOR to the development of special relativity. In Newtonian physics, nothing special happens to time when you travel at c.
__________________
"As long as it is admitted that the law may be diverted from its true purpose -- that it may violate property instead of protecting it -- then everyone will want to participate in making the law, either to protect himself against plunder or to use it for plunder. Political questions will always be prejudicial, dominant, and all-absorbing. There will be fighting at the door of the Legislative Palace, and the struggle within will be no less furious." - Bastiat, The Law
Ziggurat is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 09:45 AM   #1116
SDG
Muse
 
Join Date: Jul 2018
Posts: 895
Originally Posted by Ziggurat View Post
Stop asking stupid questions.



You missed the entire point, which was that Einstein was asking this in the context of Newtonian physics, since this was PRIOR to the development of special relativity. In Newtonian physics, nothing special happens to time when you travel at c.
A spaceship is traveling at close to c speed.
The length contraction is real.
How do we (from the outside) observe longitudinal and transverse waves of all the fields on the spaceship?
All the atom interactions of the spaceship?
Let us assume the spaceship is contracted to 1mm.
How do we analyze the physics of the 100m spaceship - the Maxwell equations?
What would be an interaction between the spaceship and the CMB?
SDG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 05:36 PM   #1117
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Exclamation SDG resorts to asking irrelevant and nonsensical questions

Originally Posted by SDG View Post
A spaceship is traveling at close to c speed. ...
SDG resorts to asking irrelevant and nonsensical questions to waste our time.
  • Irrelevant gibberish of "longitudinal and transverse waves" on the spaceship.
  • Irrelevant idiocy of observing all of the atomic interatctions on the spaceship.
  • Irrelevant "analyze the physics of the 100m spaceship" idiocy.
  • Irrelevant spaceship and CMB nonsense.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 05:57 PM   #1118
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Exclamation SDG lies about Einstein's classical chasing light scenario

Originally Posted by SDG View Post
The bold part?
So, gamma rays should not hurt me?
SDG lies about Ziggurat's post which was the fact that there is light with wavelengths longer than people. That light is at the opposite end of the spectrum to gamma rays - thus the lie.
Also: SDG resorts to asking irrelevant and nonsensical questions to waste our time.

SDG lies with http://www.pitt.edu/~jdnorton/papers/Chasing.pdf which is the 16 year old Einstein thinking about chasing a beam of light using classical physics. This was 10 years before Einstein applied Planck's quantization to light to get photons.

SDG lies with "This does not make sense." when Einstein made classical physics sense where light is electromagnetic waves.

"no observer (observer has mass) can be observing any oscillation." stupidity. Einstein performed a thought experiment in classical physics where an observer can travel at any speed.

"There is no time, no oscillation" stupidity when there is time and oscillations in both electromagnetic light and photons. Photons have an energy E = hc/wavelength!

Last edited by Reality Check; Today at 06:09 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old Today, 06:08 PM   #1119
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 27,450
Exclamation SDG descends to asking obviously stupid and irrelevant questions

Originally Posted by SDG View Post
No, this is not a stupid question. ...
SDG descends to asking obviously stupid and irrelevant questions to waste our time.

A stupid "does it follow from the Special Relativity that a spaceship cannot reach and travel, let say at 0.7c or 0.866 ..." question when SDG has a relativity textbook which says SR imposes no such limits. Ending with "...because the spaceship would be getting close to vaporizing?" stupidity when when SDG has a relativity textbook where there will be no such "vaporizing" from SR. That will be a limit from the friction of the spaceship travelling thru gas.
A stupid and irrelevant question about a "transverse electric wave (polarized light) going across the spaceship" and outside observers. It is stupid because it will be either inside the spaceship and obviously not visible to anyone outside it, or outside and detectable.

Last edited by Reality Check; Today at 06:13 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Reply

International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 07:12 PM.
Powered by vBulletin. Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.

This forum began as part of the James Randi Education Foundation (JREF). However, the forum now exists as
an independent entity with no affiliation with or endorsement by the JREF, including the section in reference to "JREF" topics.

Disclaimer: Messages posted in the Forum are solely the opinion of their authors.