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Author Topic:   Misconceptions in Relativity
Straggler
Member
Posts: 10327
From: London England
Joined: 09-30-2006
Member Rating: 2.5


Message 76 of 141 (509753)
05-24-2009 11:32 AM
Reply to: Message 75 by cavediver
05-24-2009 11:24 AM


Re: Vanish The Sun
Then I stand as demonstrably "misconceived" and now educated. My congrats to Nosy for his superior knowledge.

I now go off to hide my public shame.

But I have learnt something which must after all be the point of this thread.

More annoyingly misconceived questions to follow.... :D


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slevesque
Member (Idle past 3265 days)
Posts: 1456
Joined: 05-14-2009


Message 77 of 141 (509786)
05-25-2009 12:28 AM
Reply to: Message 66 by Percy
05-24-2009 8:46 AM


I knew what a citation was, but i didn't know of the concept CD described (comparing papers threw their numbers of citations)

Edited by slevesque, : No reason given.


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 Message 66 by Percy, posted 05-24-2009 8:46 AM Percy has not yet responded

  
Straggler
Member
Posts: 10327
From: London England
Joined: 09-30-2006
Member Rating: 2.5


Message 78 of 141 (509808)
05-25-2009 8:40 AM
Reply to: Message 75 by cavediver
05-24-2009 11:24 AM


Re: Vanish The Sun
*We* haven't - we are a long way from the Sun. All we care about is how much mass/energy is contained within our orbital radius. We don't give a damn how dense it is, just so long as it is a spherically symmetric distribution. Blow the Sun up, and as long as the entire debris cloud remains within our radius, and remains spherically symmetric, we'll keep orbiting. Likewise, should the Sun collapse. The only difference the collapse will make is that we can know get much closer to the interesting parts of the Solar space-time: r=2M (the event horizon, about 3km for the Sun), and r=0 (the singularity). Normally, we cannot encounter these regions of space-time as they don't exist, as the Sun occupies that space.

I have been thinking about this and have come to appreciate just how dum my previous response in fact was. Embarressingly so in fact.

However it does raise the folowing question: Where do "we" need to be in order to be affacted by the (hypothetical again) transition of our Sun into a black hole? Would it only affect bodies on the surface of the Sun or (somehow) within it's radius? Or would a body in close enough orbit be affected in any way by this restructuring of spacetime that makes up the focus of that orbit?


This message is a reply to:
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cavediver
Member (Idle past 2268 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 79 of 141 (509816)
05-25-2009 9:32 AM
Reply to: Message 78 by Straggler
05-25-2009 8:40 AM


Re: Vanish The Sun
Or would a body in close enough orbit be affected in any way by this restructuring of spacetime

If the Sun were to simply collapse inwards, maintaining spherical symmetry, there is absolutely no change to space-time outside of the Sun's original volume. The only space-time that would change would be in the new "space" left behind as the Sun collapses. SO if you were in orbit, just above the Sun's surface, you woudld remain in that orbit. To experience any of the "weirdness" of the new space-time, you would have to venture inwards into the newly accessible depths of the Sun's original core. It starts to get fun a few km from the centre.


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lyx2no
Member (Idle past 3341 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 80 of 141 (510163)
05-28-2009 8:01 AM
Reply to: Message 78 by Straggler
05-25-2009 8:40 AM


The Sun Becomes a Black Hole
Not be tedious, but I wanted to get an idea of how g would change as we got closer to the center of the Sun compared to the center of an equal mass black hole. In another thread it was mentioned that there would be no net g inside a shell. I, therefore, assumed I would only have to contend with the mass inside of a radius to determine the net g that would be experienced. I was unable to find a table for ρ as a function of r to get the amount of mass inside r so I sort of guessed my own: 0<ρ<6; logρ=-0.7r+5.2•105 kg/m3 and a bit of fudge. That very well might have made the exercise silly, but I'd think it could be close enough to have some value. It does behave as I suspected it would. Since I went to the trouble of doing the work I might as well share it.

Distance = r (x108 m)         Acc. with Sun (m/s2)         Acc. with black hole
10 133 133
9 164 164
8 207 207
We're now just above the surface about to enter the body of the Sun.
7 271 271
6 368 368
5 526 530
4 800 830
3 1220 1480
2 2090 3320
1 3540 13300
.9 3190 16400
.8 2835 20700
.7 2480 27100
.6 2130 36900
.5 1760 53100
.4 1417 82900
.3 1070 147000
.2 717 332000
.1 354 1330000
0 0 ∞

Of course, because relativistic effects. it doesn't really go to infinity, but I've haven't a clue as to how that would be calculated.

I trust someone will let me know if I've done something obviously stupid.


Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them.
— Thomas Jefferson

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cavediver
Member (Idle past 2268 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 81 of 141 (510165)
05-28-2009 8:08 AM
Reply to: Message 80 by lyx2no
05-28-2009 8:01 AM


Re: The Sun Becomes a Black Hole
I was unable to find a table for ρ as a function of r to get the amount of mass inside r so I sort of guessed my own...

Try this page on polytropes.


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lyx2no
Member (Idle past 3341 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 82 of 141 (510191)
05-28-2009 4:20 PM
Reply to: Message 81 by cavediver
05-28-2009 8:08 AM


Re: The Sun Becomes a Black Hole
Thank you, cavediver. I'm surprised, I thought I was being daring but I didn't make the gradient nearly steep enough. This makes the peak higher and nearer the center. The over all shape is the same, however.


Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them.
— Thomas Jefferson

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 Message 81 by cavediver, posted 05-28-2009 8:08 AM cavediver has not yet responded

  
Smooth Operator
Member (Idle past 3739 days)
Posts: 630
Joined: 07-24-2009


Message 83 of 141 (516292)
07-24-2009 1:44 PM
Reply to: Message 30 by cavediver
05-17-2009 3:30 PM


quote:
I'm sure you're aware from SR that we have time dilation and length contraction. These are purely observational effects, resulting from observing 4d space-time from a 3d perspective.
Actually they are not obervational facts. They are interpretations of observational facts. The time dilation effect that has been observed can be explained as clock's mechanism slowing down.

quote:
Assuming a model of aether non-entrained by the motion of celestial bodies, one can provide a rational explanation of the experimental processes affecting the measurement of time when clocks are in motion. Contrary to special relativity, aether theory does not assume that the time itself is affected by motion; the reading displayed by the moving clocks results from two facts: 1/ Due to their movement through the aether, they tick at a slower rate than in the aether frame. 2/ The usual synchronization procedures generate a synchronism discrepancy effect. These facts give rise to an alteration of the measurement of time which, as we shall show, exactly explains the experimental results.
http://arxiv.org/abs/physics/0611077

And the lenght contraction has actually never been observed.


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Replies to this message:
 Message 84 by cavediver, posted 07-25-2009 11:24 AM Smooth Operator has responded

  
cavediver
Member (Idle past 2268 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 84 of 141 (516474)
07-25-2009 11:24 AM
Reply to: Message 83 by Smooth Operator
07-24-2009 1:44 PM


http://arxiv.org/abs/physics/0611077

Well, let's take a look and see if this is worth reading...

abstract writes:

In particular, they enable to solve an apparent paradox that special relativity cannot explain (see chapter 4).

Interesting - this has to be worth a read:

According to conventional relativity, contrary to aether theory, nothing differentiates the co-ordinate systems 0 S and 1 S , because there is no preferred inertial frame; in other words, motion is only relative, and one can consider that 0 S moves relative to 1 S , in the same way as 1 S is moving relative to 0 S . Therefore SR predicts a complete symmetry between the frames: for example, a
clock in 1 S slows down with respect to a clock standing in 0 S , but conversely a clock in 0 S is subjected to slow down with respect to a clock in 1 S . Of course this result appears paradoxical. It defies logic and cannot be rationally explained if this total equivalence between frames is assumed. Yet, as we shall see, the paradox can be solved if we assume the existence of a preferred aether frame in which case the measurements are affected by systematic distortions, and the complete symmetry proves only apparent.

And there we have it - abject stupidity, parading as science. Since when is science advanced by claims of "defies logic and cannot be rationally explained"

As the kids say, epic fail


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Replies to this message:
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Smooth Operator
Member (Idle past 3739 days)
Posts: 630
Joined: 07-24-2009


Message 85 of 141 (516488)
07-25-2009 2:48 PM
Reply to: Message 84 by cavediver
07-25-2009 11:24 AM


quote:
And there we have it - abject stupidity, parading as science. Since when is science advanced by claims of "defies logic and cannot be rationally explained"
So you basicly don't have an argument, fine... It would been easier if you said it like that.

Let me explain something to you. The first thing in science is that something has to be logicals to be correct. If it is not logical, than it is not correct. So if you have a theory that says, for an example let's say, that an object can go in two different directions in same time, you have an illogical theory, which is wrong.

So SR fail the first test to be a real scientific theory.


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Replies to this message:
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cavediver
Member (Idle past 2268 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 86 of 141 (516491)
07-25-2009 2:59 PM
Reply to: Message 85 by Smooth Operator
07-25-2009 2:48 PM


So you basicly don't have an argument, fine...

I don't have an argument because there is nothing to argue. The symmetry of time dilation in S.R. is not paradoxical, it is bloody obvious if you have the first clue about the theory. The reason the Twins' Paradox is so-called, is because the ASYMMETRY is (incorrectly) regarded as paradoxical. Not appreciating this, yet thinking that one can write a critique of S.R. just makes one an idiot and a laughing-stock...


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Replies to this message:
 Message 87 by Smooth Operator, posted 07-25-2009 3:06 PM cavediver has responded

  
Smooth Operator
Member (Idle past 3739 days)
Posts: 630
Joined: 07-24-2009


Message 87 of 141 (516494)
07-25-2009 3:06 PM
Reply to: Message 86 by cavediver
07-25-2009 2:59 PM


quote:
I don't have an argument because there is nothing to argue. The symmetry of time dilation in S.R. is not paradoxical, it is bloody obvious if you have the first clue about the theory. The reason the Twins' Paradox is so-called, is because the ASYMMETRY is (incorrectly) regarded as paradoxical. Not appreciating this, yet thinking that one can write a critique of S.R. just makes one an idiot and a laughing-stock...
The point was not even the Twin Paradox. You obviously don't know what I'm talking about.

I was trying to explain to you, that time dilation was not actually observed and that it can be explained by clock's mechanism slowing down, and not the time itself slowing down.


This message is a reply to:
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Replies to this message:
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 Message 90 by DevilsAdvocate, posted 07-25-2009 4:30 PM Smooth Operator has responded

  
cavediver
Member (Idle past 2268 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 88 of 141 (516495)
07-25-2009 3:12 PM
Reply to: Message 87 by Smooth Operator
07-25-2009 3:06 PM


The point was not even the Twin Paradox. You obviously don't know what I'm talking about.

the cluelessness is strong with this one

I was trying to explain to you, that time dilation was not actually observed and that it can be explained by clock's mechanism slowing down, and not the time itself slowing down.

I know - but that doesn't change the obvious facts that, 1) you are completely wrong, and 2) you are so out of your depth, that you have no clue as to the fact you are wrong.

Tell me, when the physicist-engineers designed the LHC, did they use the mathematics of Special Relativty, or your bullshit?


This message is a reply to:
 Message 87 by Smooth Operator, posted 07-25-2009 3:06 PM Smooth Operator has responded

Replies to this message:
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Smooth Operator
Member (Idle past 3739 days)
Posts: 630
Joined: 07-24-2009


Message 89 of 141 (516497)
07-25-2009 3:20 PM
Reply to: Message 88 by cavediver
07-25-2009 3:12 PM


[/quote]the cluelessness is strong with this one[/quote]Why don't you ask your mom how strong it is?

quote:
I know
No, you don't know. If you did you wouldn't go off topic.

quote:
- but that doesn't change the obvious facts that,
Yes it does, since it explains why you are switching topics.

quote:
1) you are completely wrong,
Explain why.

quote:
2) you are so out of your depth, that you have no clue as to the fact you are wrong.
Explain why?

quote:
Tell me, when the physicist-engineers designed the LHC, did they use the mathematics of Special Relativty, or your bullshit?
When your mom screems, does she think of you or, me at night?

This message is a reply to:
 Message 88 by cavediver, posted 07-25-2009 3:12 PM cavediver has responded

Replies to this message:
 Message 91 by DevilsAdvocate, posted 07-25-2009 4:32 PM Smooth Operator has responded
 Message 92 by cavediver, posted 07-25-2009 5:58 PM Smooth Operator has responded

  
DevilsAdvocate
Member (Idle past 1726 days)
Posts: 1548
Joined: 06-05-2008


Message 90 of 141 (516506)
07-25-2009 4:30 PM
Reply to: Message 87 by Smooth Operator
07-25-2009 3:06 PM


Smooth Operator writes:

I was trying to explain to you, that time dilation was not actually observed and that it can be explained by clock's mechanism slowing down, and not the time itself slowing down.

Without the time dilation phenomena as described in SR, the GPS navigation and locating services would be an impossibility. It is only by taking time dialation into effect that we can achieve accurate localization using the global positionitioning satellite system in all types of navigational applications from the military to the Tom Tom in your SUV.

The aether hypothesis has been dead for over 100 years. Only crackpots and nutcases continue to breath life into this idea.


For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
Dr. Carl Sagan

This message is a reply to:
 Message 87 by Smooth Operator, posted 07-25-2009 3:06 PM Smooth Operator has responded

Replies to this message:
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