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Who's familiar with the conversion? - "In 15 years' ship-time they could reach Andromeda

 
 
layman
 
  1  
Reply Wed 2 Dec, 2015 12:33 am
As shown, suggestions have been made by various prominent scientists (I've only mentioned a few) that the choice between SR and LR could have an EXTREMELY significant effect on many other areas of science. So in that sense it is a very important question. I have seen some predict that history will look back on this era of science as a "dark age" which will be scoffed at by future scientists, in large part because SR and the subjective elements it incorporates (which have spread to many other areas of physics) are antithetical to objective science. The result is that physics has become highly mathematical, with little attention paid to how well, if at all, the math actually corresponds to some coherent, plausible view of "reality."

There is a very subtle, yet very significant, difference between SR and LR which can be briefly summarized like this:

1. LR says that, due to time dilation (slowing clocks) and length contraction we always MEASURE the speed of light to be constant. But the implication is that it is NOT "actually" constant. We ONLY measure that way because our measuring instruments have been distorted (Bell talked about this in the passage I quoted).

2. SR says the speed of light actually IS constant. The difference is subtle, and maybe not too striking at first glance. But it's implications go far and wide. It leads to views of space and time that are totally counter-intuitive, and which could well be just plain wrong. It may be these false space/time views that raise problems (such as accelerating expansion of the universe) which are only APPARENT. By "apparent" I simply mean "not really there." They don't actually "appear" to us. A better word would probably be "imaginary," since they can never be observed empirically and are products of imagination. Kinda like ghosts, ya know?
layman
 
  1  
Reply Thu 3 Dec, 2015 12:15 am
@layman,
Quote:
It leads to views of space and time that are totally counter-intuitive, and which could well be just plain wrong.


"Speed" is a product of time and distance, NOT the other way around. To determine speed, one must FIRST know the amount of time and distance involved. Speed = the amount of distance travelled (D), divided by the amount of time it took to travel that distance (T). So S=D/T.

If I go 100 miles (D) in one hour (T), then S=100 miles in 1 hour, i.e., 100 mph. I cannot know the speed UNTIL I first know the time and distance.

If you ask me how far it is to a certain town, and I say it's "an hour from here," then I have NOT answered your question. You asked a question about distance, and I responded with an answer about time. Obviously, the time it took to get there would be totally dependent on how fast you travelled.

But suppose I told you that, no, it doesn't matter how fast you go, you will always get there is exactly one hour. Would that make sense? On the face of it, no. But, if it's in any sense "true," then it can be explained in different ways. (see next post)
layman
 
  1  
Reply Thu 3 Dec, 2015 12:40 am
@layman,
Suppose a town is 100 miles away and I tell two different guys how to get there, and they leave at the same town. A drives 100 mph, B drives 50 mph. They both call me later to tell me how accurate my estimates of distance (by way of time) were.

A says: You were right, it took me exactly an hour to get here.
B says: You were completely wrong, it took me 2 hours, not 1 hour, to get here.

What do I tell B? Well, there are a number of possibilities, such as:

1. No, it's only been an hour since you left. Your watch must have slowed down.
2. Well, your odometer must be broken if it says you went 100 miles. You've actually gone 200 miles, and you're in a different town than you think.
3. I could give many different combinations of "explanations" which combine supposed instrumental errors in some fashion. I could say, for example: Your watch is slow AND your odometer is off. I won't bother working out a specific example (such as your watch is 10 minutes slow and your odometer is off by x percent), I'm sure you get the idea.

Now, those explanation, weird as they seem, are at least possible. Of course it's also possible that I was simply wrong in assuring B that it was "1 hour away." But since I'm ALWAYS right, let's just say that's not possible.

But suppose B tells me: "Layman, you're plumb fulla ****. I'm not in the wrong town. I'm sitting here in the hotel lobby with A, and he tells me he's been here for an hour, waiting for me."

What can I say now? I know! I tell him that simultaneity is "relative," that's what! So, I say: "No, he didn't get there an hour ago, you both got there at exactly the same. He only thinks he's been there an hour. But he just now got there too. You two just have different concepts of what's "simultaneous," that's all."

He'll buy that!

Won't he?
layman
 
  1  
Reply Thu 3 Dec, 2015 01:12 am
@layman,
Of course I could have explained part of the difference to B without referring to speedometers or odometers.

I could have just said: "Well, ya see, "space" changed. For him, space stayed the same. For you it didn't. For you, space doubled, and got twice as long. That's why it took you two hours."

Sounds reasonable, doesn't it? I mean the exact same space can be both 100 miles AND 200 miles, right? It can all work mathematically, I tellya! Go get me my slide rule and I'll PROVE to you that space doubled.

Or how about this: For you time changed. Your watch was fine, but "time" changed for you (but not A). Once again, if you don't believe that, I've got this here trusty slide rule right in my pocket.

layman
 
  1  
Reply Thu 3 Dec, 2015 01:28 am
@layman,
See the issue (as far as math goes) yet, Max?
0 Replies
 
layman
 
  1  
Reply Thu 3 Dec, 2015 01:33 am
@layman,
Correction (too late to edit). A couple posts up, I wrote:

Quote:
Suppose a town is 100 miles away and I tell two different guys how to get there, and they leave at the same town


It if it isn't otherwise obvious, I meant to say:

Quote:
Suppose a town is 100 miles away and I tell two different guys how to get there, and they leave at the same TIME.


Not "town," but the scenario does assume that they both leave from the same place at the same time.
layman
 
  1  
Reply Thu 3 Dec, 2015 01:56 am
@layman,
I'll give one more example which is designed to show some of the practical differences between an SR and an LR interpretation.

Suppose I have a football field where the goal posts are exactly 100 yards apart.

A spaceship flies by at near light speed and concludes that the goal posts are only 50 yards apart. How can this be explained? Well, two ways:

1. Because he is travelling so fast, he thinks my yardsticks are only half the size of his. Sure, it's true that 100 of *my* yardsticks will fit between those two goal posts, but only 50 of his will (because they are, to him, twice as long as mine are). So he measures it to be 50 yards, while I measure it to be 100 yards. We're just using two yardsticks of different lengths, that's all. The distance hasn't actually changed in the least.

2. The space between the two goals posts has "actually" shrunk. When he flew by, the two goal posts moved closer to each other. Once he flew by, the space expanded again, and the posts went back to being 100 yards apart.

Which makes more sense, ya figure? What if I'm sitting there at the 50 yard line when he flies by? Do the posts move selectively (not at all for me, but only for him)?
layman
 
  1  
Reply Thu 3 Dec, 2015 02:49 am
@layman,
A partial repost, from page 1:

Quote:
From the site you cited, Max:


Quote:
You might wonder how the spaceship accelerating at 1g can travel 490 light years in 12.1 years if nothing can travel faster than light. The answer is that the spaceship doesn’t travel 490 light years - the Lorentz contraction caused by its high speed means it travels a much shorter distance.


How does it "travel" a shorter distance than it is?


http://able2know.org/topic/301703-1#post-6065785

Like many others, that question never got answered.

It says: "...the Lorentz contraction caused by its high speed means it travels a much shorter distance." Does a mathematical "contraction" actually shorten the distance? Does a math formula (which is what's being referred to here when it mentions a "Lorentz contraction") MAKE space shrink, if you decide to use it in your "analysis?"
0 Replies
 
layman
 
  1  
Reply Thu 3 Dec, 2015 03:39 am
@layman,
Quote:
"Speed" is a product of time and distance, NOT the other way around. To determine speed, one must FIRST know the amount of time and distance involved.


In effect, special relativity gets it completely backwards. It first tells you what the speed MUST be (without knowing the time or distance).

Once you know what the speed must be, you can now (and only now) start trying to DEDUCE what the time might be and/or what the distance might be. Just make sure it ALWAYS comes out to be the speed I've TOLD you is HAS to be.

This is not "empirical" science. It is a priori metaphysics

Suppose I told you: Without doubt, there is a god who is omniscient, omnipotent, and omnibenevolent. Now, I tell you, go out and start looking around in the world, and come back to me with your explanations of what you see and why you see it.

Just remember this, whatever you see, the only acceptable explanation must be consistent with what we already know about god.
0 Replies
 
layman
 
  1  
Reply Thu 3 Dec, 2015 05:27 am
@layman,
Quote:
1. Because he is travelling so fast, he thinks my yardsticks are only half the size of his. Sure, it's true that 100 of *my* yardsticks will fit between those two goal posts, but only 50 of his will (because they are, to him, twice as long as mine are). So he measures it to be 50 yards, while I measure it to be 100 yards. We're just using two yardsticks of different lengths, that's all. The distance hasn't actually changed in the least.

2. The space between the two goals posts has "actually" shrunk. When he flew by, the two goal posts moved closer to each other. Once he flew by, the space expanded again, and the posts went back to being 100 yards apart.


In case it's not clear, 1 is LR and 2 is SR.

When he first published his theory in 1905, Al simply "lifted" Lorentz's equations from a totally different type of theory because it gave him the math he needed to get the correct predictions.

But the Lorentz transforms don't really fit his theory, especially as espoused by Minkowski after about 1907. The transform has a factor which adjusts for "length," and it refers to the lengths of measuring rods, such as yardsticks.

Length is not distance. Length is the measurement from one end of a thing to the other. Distance is the measurement BETWEEN two different things.

In order to try to give some sense of meaning to the LT, as used by SR, it had to be misconstrued by SR. SR treated the length contraction as a "distance" contraction--which is wrong. But, even assuming that is a proper interpretation of the LT, it would still make no sense. Space doesn't contract, we know that. The actual length of a material object can, and does, contract under changing circumstances (such as temperature changes).

The math will work either way. That's not what you're choosing between when deciding which theory (LR or SR) gives a more sensible interpretation of "reality." Both theories use the LT. They just interpret and apply it differently.

A given length, such as that of a football field, can be mis-measured in different ways by 10 (or an infinite number of) different observers but that will never affect the football field itself. On the other hand, the football field can't ACTUALLY be 10 different lengths, all at the same time.
0 Replies
 
layman
 
  1  
Reply Mon 7 Dec, 2015 04:46 pm
@maxdancona,
Well, it seems like those who bust in with dogmatic claims and empty platitudes really don't have much participation to offer when it comes to defending their views, answering questions, discussing particular ideas of concern, or the like, eh?

What else is new? They don't come here to discuss ideas to begin with. They only come to assert that their preconceived indoctrination and peer-approved dogma is indubitable. In their minds, doing that answers all questions and proves all "facts."
0 Replies
 
layman
 
  1  
Reply Fri 18 Dec, 2015 02:21 pm
From Max, via another thread:

Quote:
My understanding of your posts on the Special Relativity thread is that you disagree with me on two main issues

1) You don't agree that Physics has a correct answer based on mathematics and experiment.

2) You don't agree that Special Relativity is correct Physics as shown by both experiment and mathematics.

Correct me if I misunderstand your position on either of these points.

Feynman agrees with me on both of these points (or I should say, I agree with Feynman).


You do not summarize my position properly. I have repeatedly stated it to you several times in this thread, and many times elsewhere. I don't care to do it again. Re-read this thread if you want to understand my position.

You might also look at this post, and the one following it, from another thread where I discuss Feynman and his notion of science vs. "cargo cult science" (pseudo-science).

http://able2know.org/topic/305125-27#post-6090649
layman
 
  1  
Reply Fri 18 Dec, 2015 02:31 pm
@layman,
Quote:
You might also look at this post, and the one following it, from another thread where I discuss Feynman and his notion of science vs. "cargo cult science" (pseudo-science).


For convenience, I'll just repost it here:

Quote:
In order to assess whether or not science is being attacked, you first have to know what science is. Richard Feynman gave a talk addressing the question: "What is science." I think he has some very good points to make.

http://www.fotuva.org/feynman/what_is_science.html

Here's one except:

Quote:
When someone says, "Science teaches such and such," he is using the word incorrectly. Science doesn't teach anything...

Science is the belief in the ignorance of experts
.


As I understand him, Fenyman says that learning scientific definitions, mathematical formulas, the steps in the so-called "scientific method," etc., is NOT science. Knowing such things does not entail that a person knows anything of substance. Learning them produces "experts," but it is merely "pseudo-science" to use them as a matter of form. That's what he called "cargo cult science."

There are many experts out there, but to be scientific you must believe in their ignorance, Feynman says.

Quote:
It is necessary to learn the words [but] it is not science...It is not science to know how to change Centigrade to Fahrenheit.

It is not easy to understand energy well enough to use [the word] right. [It displays no understanding to say] "energy makes it move." It would be equally well to say that "God makes it move," or "spirit makes it move," or "movability makes it move."


As Ambrose Bierce aptly said:

Quote:
“Education is that which discloses to the wise and disguises from the foolish their lack of understanding.”
maxdancona
 
  1  
Reply Fri 18 Dec, 2015 03:09 pm
@layman,
You are pulling random quotes about Feynman out of context. Feynman taught Special Relativity. Feynman taught that the correct scientific explanation of nature is understood through mathematics and experiment.

Here is Feynman's lecture on Special Relativity.

http://www.feynmanlectures.caltech.edu/I_15.html

And here is Feynman's response to the psuedo-scientific nonsense that Layman is slinging on this thread.

Feynman wrote:
... you’ll have to accept it because it’s the way nature works. If you want to know the way nature works, we looked at it, carefully. That’s the way it works.

You don’t like it…, go somewhere else!

To another universe! Where the rules are simpler, philosophically more pleasing, more psychologically easy. I can’t help it! OK! If I’m going to tell you honestly what the world looks like to the… human beings who have struggled as hard as they can to understand it, I can only tell you what it looks like.

And I cannot make it any simpler, I’m not going to do this, I’m not going to simplify it, and I’m not going to fake it. I’m not going to tell you it’s something like a ball bearing inside a spring, it isn’t.

So I’m going to tell you what it really is like, and if you don’t like it, that’s too bad.


You are free to come up with your own ideas about science that feel right to you. But, that was not what Feynman was about. Feynman taught that Special Relativity, as confirmed by mathematics and experiment, is the correct scientific view of how nature works.

Feynman is a role model of mine and has been since I studied Physics in the University. I have read much of his work including his lecture series. What I am saying on this thread, that the correct science answer is based on mathematics and experiment... and that this includes Special Relativity... coincides with what Richard Feynman taught during his impressive life.
layman
 
  1  
Reply Fri 18 Dec, 2015 03:45 pm
@maxdancona,
I can't find the language you quote anywhere in the citation you provide.
maxdancona
 
  1  
Reply Fri 18 Dec, 2015 04:01 pm
@layman,
It is from his introduction to his lectures on Quantum Electrodynamics at Cornell

layman
 
  1  
Reply Fri 18 Dec, 2015 04:08 pm
@maxdancona,
I haven't read this whole lecture, but, from scanning it, I don't see anything I would disagree with. He also make points which I have made after you denied them (such as the meaning of Galilean relativity).

Feynman also address a couple of points I have been making, such as:

Quote:
Before the man took it aboard, he agreed that it was a nice, standard clock, and when he goes along in the space ship he will not see anything peculiar. If he did, he would know he was moving—if anything at all changed because of the motion, he could tell he was moving.


Note that Feynman says that the guy is, by hypothesis, MOVING. He then says: "he will not see anything peculiar. If he did, he would know he was moving." He IS moving, BUT, in accordance with the requirements of SR, he is not allowed to KNOW it. That is why he "sees" (this only means calculates, and has nothing to do with vision or any other sense perception) things the way SR tells him he must.

So, per Feynman:
1. He is moving
2. But SR does not allow him to acknowledge that fact.
0 Replies
 
layman
 
  1  
Reply Fri 18 Dec, 2015 04:10 pm
@maxdancona,
OK, so it has nothing to do with anything he said about special relativity. That's what I thought.
maxdancona
 
  1  
Reply Fri 18 Dec, 2015 04:31 pm
@layman,
That video shows that Feynman teaches that the correct scientific view is determines by mathematics and experiment. You can't just make up what feels right to you.

Feynman explains the correct view of special relativity here...

http://www.feynmanlectures.caltech.edu/I_15.html

You can read it for yourself. This is the correct scientific view of how nature works.
layman
 
  1  
Reply Fri 18 Dec, 2015 04:32 pm
@maxdancona,
A very enjoyable video, it's too bad that it got cut short because what he was going to say next was extremely important.

But YOU want to talk about ME quoting selectively!? 95% of this clip involves saying we DONT understand QM. At the outset he says what he can explain is the mathematical models which seem to "predict" what we will see, the "theory" he calls it.

The model is OK for predictions. It is NOT OK for comprehensibility. It "models" (i.e., predicts) what we see, that's all. It is not "true," just reliable. Kinda like SR, eh?
 

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