Black holes

[Farsight]

..."What Einstein Thought" is a conversation you are having with others, which I have very little interest in. The history of physics is of no relevance to the empirical data I am asking for.

You've had your empirical data. You dismiss it just as you dismiss Einstein.

 

[Farsight]

... You never did engage in debate. You tried to lecture someone who knows more than you. But that's all you've done with pretty much everyone here.

Only you don't know more than me, now do you? We're done Zig, stop whining.

 

[Farsight]

The empirical evidence is simply the measurements made in experiments. You can now compare those to the predictions made by the theory. Those predictions are quantitative.

No problem.

So, let's say I've got a clock on the ground at sea level and another on a satellite in GEO. Are you saying that MTW GR predicts (quantitatively remember) that they will read the same?

No. How can you possibly think that after everything we've discussed?

If not, clearly the empirical evidence is consistent with the speed of light being constant.

Not when it's a light clock.

 

[DeiRenDopa]

Using the 'parallel-mirror light clock as a game of pong' illustration in Brian-M's post, it may be possible to show more clearly that Farsight's claim of a variable speed of light is somewhat more radical than he has stated.

Use the upper ("low gravity") clock to time the packets of light (may we call them photons? ) in the lower ("high gravity") one. Apply Farsight's method for calculating the speed of light, c, in the lower clock. c, as measured this way, will be different than c, calculated by someone co-located with the lower clock (details later).

Now image another pair of games of pong parallel-mirror light clocks, located above the upper one; call these the "lower gravity" (the bottom one of the new pair) and the "even lower gravity" clocks (the top one).

Again apply Farsight's method for calculating the speed of light, c, in the original, lower clock (the "high gravity" one), only this time use as our standard clock the "lower gravity" one. c, as measured this way, will be different than c, calculated by someone co-located with the "high gravity" clock.

And it will also be different from the value for c calculated using the "low gravity" clock!

That's three different values for c.

Now repeat, using as our standard clock the "even lower gravity" one. Once again, a different c. We're up to four now.

Now image another pair of games of pong parallel-mirror light clocks, located ...

Conclusion: using the Farsight method, the speed of light at any location can have many different values, simultaneously. It all depends on which clock you choose as your standard ...

That's my post, in full.

Here's how Farsight responded:

...That's three different values for c.

...We're up to four now...

...Conclusion: using the Farsight method, the speed of light at any location can have many different values, simultaneously. It all depends on which clock you choose as your standard ...

Nope. You just look at the two light clocks. The lower clock runs slower than the upper clock because the light's going slower there:

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=721&pictureid=5752[/qimg]

Conclusion: what you don't do is try to hide the obvious with obviously facile assertions. People aren't that stupid.

Clearly, I failed to communicate my meaning to Farsight^.

So, let me try again.

Here is a pair of parallel-mirror clocks (P-MLCs), per Farsight, but with a snapshot of Brain-M's bouncing light packets. The asterisks represents positions of the light packets. The P-MLCs are labeled. Per Farsight, P-MLC A is at a lower elevation than P-MLC Q. Here the light packets have just left the starting gate left-hand mirror:

|*-*-*-*-*-*-*-*-*-*-*-*| Q
|*-*-*-*-*-*-*-*-*-*-*-*| A

And here the light packet in P-MLC Q has reached the buffer right-hand mirror:

|*-*-*-*-*-*-*-*-*-*-*-*| Q
|*-*-*-*-*-*-*-*-*-*-*-*| A

The distance between the mirrors, in both P-MLCs, is 12 units; call these units btrs, abbreviated b. The P-MLCs 'tick' once per second; i.e. when the light packet reaches the right-hand mirror, one (local) second has elapsed (from the time the light packet left the left-hand mirror). The local speed of light - which is always the same (even Farsight agrees) - in these units is 12 btrs per second, b/s for short.

Per Farsight, the speed of light at location A is 3 b/s, when measured by the (distant) P-MLC Q.

Everything OK so far? As in, this is all exactly as Farsight prescribes ...

Now consider another P-MLC, at a different location (elevation). Label this one F. As F is at a higher elevation, the Farsight diagram is much the same (I'm not going to repeat the 'light packets at the starting gate' diagram), except for the fact that F's elevation is not the same as Q's:

|*-*-*-*-*-*-*-*-*-*-*-*| F
|*-*-*-*-*-*-*-*-*-*-*-*| A

In this case the speed of light at location A is 6 b/s, when measured by the (distant) P-MLC F!

So, we have the speed of light at location A being both 3 b/s and 6 b/s!

Now if we do the experiment again, this time with all three P-MLCs, and add a ruler (to show the location of the light packets), Here's what we have:

|*-*-*-*-*-*-*-*-*-*-*-*| Q
|*-*-*-*-*-*-*-*-*-*-*-*| F
|*-*-*-*-*-*-*-*-*-*-*-*| A
|*-*-*-*-*-*-*-*-*-*-*-*| ruler

And:

|*-*-*-*-*-*-*-*-*-*-*-*| Q
|*-*-*-*-*-*-*-*-*-*-*-*| F
|*-*-*-*-*-*-*-*-*-*-*-*| A
|*-*-*-*-*-*-*-*-*-*-*-*| ruler

Questions or comments?

^ By now I'm pretty confident that, of all readers of my post (well, the subset which is the regular participants in this thread), only Farsight did not grasp my meaning.

 

[Farsight]

We don't often see an entire sequence of own goals being celebrated with such exuberance.

No own goals on my side, Clinger. Apart from in your dreams.

It isn't about believing Einstein. It's about understanding Einstein, working through the mathematical consequences of his theory of general relativity, and comparing those mathematical consequences to experiment.

No it isn't about believing Einstein. Yes it is about understanding Einstein. And to do that you don't dismiss what he said and ignore the evidence you can see with your own eyes because you've been spoon-fed a general relativity that contradicts what the guy said.

According to Einstein's general postulate of relativity, Painlevé-Gullstrand coordinates are just as good as Schwarzschild coordinates. According to Einstein, we have just as much right to describe spacetime around a black hole using Painlevé-Gullstrand coordinates as using Schwarzschild coordinates...

And according to Einstein we can assert that the Sun goes round the Earth? No. The general laws of nature are to be expressed by equations which hold good for all systems of co-ordinates does not give you carte blanch to declare that non-real solutions are real.

...Bare assertions, contradicted by evidence.

That's you to a T, Clinger. You continue to evade the evidence. Does the light in the lower clock go slower or not?

 

[Farsight]

But I don't think I'll continue arguing with you on this thread. I'm wasting a silly amount of time on this pointless and unproductive debate.

Let's wrap it up there then shall we guys?

 

[Roboramma]

No. How can you possibly think that after everything we've discussed?

Even if it's a light clock?

Not when it's a light clock.

Why? You're saying that the theory predicts exactly (quantitatively remember) what we see, but that somehow those predictions being correct is empirical evidence against the theory? That doesn't make any sense.

 

[DeiRenDopa]

There aren't any "muon decay clocks", we just see muon decay affected by time dilation just as we'd expect. It's like your parallel-mirror light-clock is good for a trillion reflections before it decays. Move it fast and you extend its lifetime as measured by an observer on earth.

A muon decay clock works like this (illustrative only):

Collect a trillion muons, and cool them so they are not moving.

Count the decays.

Your (local) time, as measured by the muon clock, is found by looking up this table: {the table is basically an integrated version of the decay function, scaled to 1 trillion}

If you'd like, I can expand this and provide more detail; for example, I could give you an example of the lookup table.

And if somebody does find that nuclear clocks don't stay synchronised with electromagnetic clocks when you change the elevation, then once somebody replicates it, then it will be accepted physics.

Per the Feynman material Brian-M provided earlier, we do not expect to find such a thing. So yes, that would be a very big deal.

 

[sol invictus]

But the speed of light is not constant, so that teaching is wrong.

Right - just like I said, you don't understand how it can be constant, given that diagram you like so much. That's your failure. Remember that line about fooling yourself?

Doesn't it bother you at all that the thing you say is wrong and contradictory can be used to correctly predict the results of all experiments, including the one illustrated in your diagram?

 

[Farsight]

Not when it's a light clock.

Why? You're saying that the theory predicts exactly (quantitatively remember) what we see, but that somehow those predictions being correct is empirical evidence against the theory? That doesn't make any sense.

I'm not saying that Robo. here's what I'm saying, it's perfectly simple: when one mechanical clock goes slower than another, it's because the cogs are going slower. When one light clock goes slower than another, it's because the light is going slower. Look at Brian's parallel-mirror light-clock gif, which is a fair representation. You can see it goes slower, just like Einstein said. And yet people will tell you that in Einstein's theory of general relativity the speed of cogs is constant and the speed of light is constant. This doesn't affect the run-of-the-mill predictions, but it does affect our understanding of black holes and the universe, and our future direction in physics and cosmology.

OK everybody, I think we've flogged this one to death and we aren't going to reach agreement, so let's call it a day.

 

[Farsight]

Not when it's a light clock.

Why? You're saying that the theory predicts exactly (quantitatively remember) what we see, but that somehow those predictions being correct is empirical evidence against the theory? That doesn't make any sense.

I'm not saying that Robo. here's what I'm saying, it's perfectly simple: when one mechanical clock goes slower than another, it's because the cogs are going slower. When one light clock goes slower than another, it's because the light is going slower. Look at Brian's parallel-mirror light-clock gif, which is a fair representation. You can see it goes slower, just like Einstein said. And yet people will tell you that in Einstein's theory of general relativity the speed of cogs is constant and the speed of light is constant. This doesn't affect the run-of-the-mill predictions, but it does affect our understanding of black holes and the universe, and our future direction in physics and cosmology.

ETA: it isn't me fooling myself here sol. Look at the gif.

OK everybody, I think we've flogged this one to death and we aren't going to reach agreement, so let's call it a day.

 

[sol invictus]

ETA: it isn't me fooling myself here sol. Look at the gif.

I've looked at it, Farsight, believe me.

You know what? It correctly represents what would happen to two light clocks held at fixed r in that metric I showed you. Remember that metric? The one you couldn't understand? Well, in that metric, that's exactly what would happen. And that metric is flat, empty space. No gravity. No black hole.

Which proves unequivocally that your argument doesn't imply its conclusion.

 

[Farsight]

The metric you wouldn't elaborate on? The one where you wouldn't say what it represented? The only thing that metric proves is that you dismiss patent scientific evidence and take refuge in mathematics.

 

[sol invictus]

The metric you wouldn't elaborate on? The one where you wouldn't say what it represented?

No, Farsight, that must be some other metric. The one I'm talking about represents flat, empty spacetime - as I told you at least seven times.

As for the mathematics required to derive or analyze that metric, it's basic general relativity, just as Einstein taught and understood it.

 

[Ziggurat]

Only you don't know more than me, now do you?

Yes, Farsight, I do.

We're done Zig, stop whining.

You said we were done last time. And yet, here we are. Funny how the things you claim, even the things which are in your power to determine, keep turning out to not be true.

 

[Ziggurat]

The metric you wouldn't elaborate on? The one where you wouldn't say what it represented?

He told you exactly what it represents. Perhaps what you really mean is you want the coordinate transforms which get you from the metric you're used to to this other metric, but that's not what you asked for. He gave you what you asked.

The only thing that metric proves is that you dismiss patent scientific evidence and take refuge in mathematics.

Yet again, the clarion call of the crank: "math isn't real!"

 

[DeiRenDopa]

I wonder if any other reader finds this, er, surreal ...

It isn't about believing Einstein. It's about understanding Einstein, working through the mathematical consequences of his theory of general relativity, and comparing those mathematical consequences to experiment.

No it isn't about believing Einstein. Yes it is about understanding Einstein.

Surreal, Part One:

Farsight claims to understand Einstein.

Thousands of others think they, too, understand Einstein. Including Wald, MTW, Will, sol, Zig, edd, W.D.Clinger, ctamblyn, ...

Many of these others do not understand Farsight's explanations of his understanding of Einstein, much less agree with it.

Farsight, apparently, has not been successful in explaining his understanding of Einstein to anyone else, in over five years (?) of trying.

Despite his many hundred (thousand?) posts, and many years of trying - without any success - Farsight continues to claim that he understands Einstein.

Surreal, no?

And to do that you don't dismiss what he said and ignore the evidence you can see with your own eyes

Surreal, Part Two.

What is this "evidence you can see with your own eyes"? Why it's the quantitative results of experiments and observations done to test GR!

Does anyone ignore any such evidence? Why, no, they don't.

Surreal, no?

because you've been spoon-fed a general relativity that contradicts what the guy said.

Surreal, Part Three.

The "general relativity" those thousands of others use, to derive the predictions that can be assessed using the quantitative results of experiments and observations done to test "general relativity", come from "what the guy said". Those derivations are available for anyone - including Farsight - to read, critique, apply, etc.

Yet there is no contradiction between theory and experiment.

Surreal, no?

Well, in this case, it may not be, not entirely.

Suppose "what the guy said" contains some contradictions, or ambiguities, or inconsistencies. If so, then one could examine everything "the guy said" and see if any of it leads to different predictions with regard to any of the experimental and observational tests that have been done. Or any that could be done, even if only in principle.

If it turns out that nothing "the guy said" leads to any such tested, or testable, empirical difference, then in what sense could those contradictions, or ambiguities, or inconsistencies be said to be relevant (other than, perhaps, to a philosopher, or a science historian)?

 

[edd]

OK everybody, I think we've flogged this one to death and we aren't going to reach agreement, so let's call it a day.

I find it delightfully meta how Farsight often claims events in this thread have reached a standstill and yet they somehow manage to continue happening for those observing it.

 

[DeiRenDopa]

... your position on fundamental particles that we discussed in the relativity+ thread. ...

For the benefit (? ) of other readers who, like me, do/did not know about this, here is that thread: Relativity+

It ran to 18 pages before JREF members stopped posting to it; this one is already longer (at 20 pages).

As with this thread, it seems that Farsight was not able to communicate his ideas in a sufficiently clear way, so that other active participants in the thread could understand them*. There are quite a few similarities in (meta-) content and style; it may be fairly accurate to say that Farsight has not learned anything significant in the last two years, in terms of how to communicate his ideas successfully.

* other than as 'crackpot nonsense', or similar.

 

[Reality Check]

But the speed of light is not constant, so that teaching is wrong.

But the speed of light is constant, so that teaching is right because when people write "speed of light" they mean the local speed oif light which is constant in GR.

You keep on demonstrating your inability to understand that the (local) speed of light is constant in GR while it is the coordinate speed of light that can vary (depending on the the coordinate system used).