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# Is there a relativist in the crowd

Brandon9000

0
Tue 4 Feb, 2014 05:11 pm
I want you to define "time at a distance" without reference to your unclear example. Give a self-contained definition. I have been familiar with Special Relativity for 45 years and have never once heard that term. And make your explanation less than 200 words.
dalehileman

1
Tue 4 Feb, 2014 05:54 pm
@Brandon9000,
Bran I had thought my example pretty straightforward: At distance d it is plus or minus d/c depending on the observer's state of motion. Beyond that I can only refer you back

Brandon9000

0
Tue 4 Feb, 2014 06:27 pm
@dalehileman,
dalehileman wrote:

Bran I had thought my example pretty straightforward: At distance d it is plus or minus d/c depending on the observer's state of motion. Beyond that I can only refer you back

That's simply the time it takes for light to travel the distance, but I get the feeling that you are falsely imbuing it with some other significance. The time it takes for light to travel a certain distance is never called "time at a distance" and why would it be? A more appropriate term would be "transit time." You appear to be incapable of giving a self-contained definition of your term "time at a distance."
dalehileman

1
Tue 4 Feb, 2014 06:57 pm
@Brandon9000,
Quote:
The time it takes for light to travel a certain distance is never called "time at a distance"
Yes, no, Bran, you'll have to forgive me if I seemed to say that t was the taad. At the moment in question the time at distance of 60 million miles is 12:00 plus or minus 5 minutes

t = 5 min = 60,000,000 mi/12,000,000 mpm

taad = present plus or minus t

Cis ya gotta forgive an occasional slip of the finger with an oldster on the threshold of Alz's, woozy trying to explain relativity

In my own defense however a rereading might have revealed several instances where its defined correctly, eg

Quote:
….it actually is 12:05 on Mars, just as it's 11:55 according to Marty. All three understand relativity and appreciate the others' viewpoint. That's what's meant by time-at-a-distance
rosborne979

1
Tue 4 Feb, 2014 07:09 pm
@dalehileman,
I give up. I've tried mightily to make some kind of sense of your examples. I've tried to simplify them and rephrase them but no matter what I do you return with something even more confusing. I'm at a complete loss to understand what you're talking about.

Perhaps if you can point us to one of the other discussion boards where someone else seemed to understand, maybe we can follow their posts and maybe make some sense of this. Otherwise I don't think we're ever going to get anywhere.
dalehileman

1
Tue 4 Feb, 2014 07:16 pm
@rosborne979,
Quote:
I'm at a complete loss to understand what you're talking about.
Yea and again Ros my apologies. Part of the problem doubtless my wording which seemed to say that was using t to represent taad rather than its range, as I admit to Bran above

Quote:
Perhaps if you can point us to one of the other discussion boards where someone else seemed to understand
Alas Ros again my sincere apologies. As I recall there were a couple of such sites and yes I have Googled for them but in one case a very persnickety Moderator who apparently didn't like me very well deleted the entire thread while the other was so long ago apparently it's been deleted from Google too

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Brandon9000

0
Tue 4 Feb, 2014 09:11 pm
@dalehileman,
dalehileman wrote:

Quote:
The time it takes for light to travel a certain distance is never called "time at a distance"
Yes, no, Bran, you'll have to forgive me if I seemed to say that t was the taad. At the moment in question the time at distance of 60 million miles is 12:00 plus or minus 5 minutes

t = 5 min = 60,000,000 mi/12,000,000 mpm

taad = present plus or minus t

Cis ya gotta forgive an occasional slip of the finger with an oldster on the threshold of Alz's, woozy trying to explain relativity

In my own defense however a rereading might have revealed several instances where its defined correctly, eg

Quote:
….it actually is 12:05 on Mars, just as it's 11:55 according to Marty. All three understand relativity and appreciate the others' viewpoint. That's what's meant by time-at-a-distance

I keep asking you for a self-contained definition of "time at a distance" without reference to your previous example and you keep telling me how the term applies to your previous example. I want a general definition of the term.
dalehileman

1
Wed 5 Feb, 2014 01:20 pm
@Brandon9000,
Quote:
I want a general definition of the term.
I was absolutely astounded Bran with a quick Googling in which the phrase apparently doesn't occur; but 'll make a valiant attempt based on my understanding

The supposed difference in the reading of a synchronized clock at a distant location based upon the observer's state of motion

Since however we're at a sort of impasse, suppose we pull out for the time being in the hope someone more familiar with the concept might eventually intervene

But again thanks all for your interest and participation

rosborne979

1
Wed 5 Feb, 2014 04:07 pm
@dalehileman,
dalehileman wrote:
The supposed difference in the reading of a synchronized clock at a distant location based upon the observer's state of motion

How do you think you read a clock at a distant location, by precognition, or by waiting for the light from the clock to get to you?
dalehileman

1
Wed 5 Feb, 2014 04:59 pm
@rosborne979,
Quote:
...by precognition, or by waiting...

By precognition. Isaac knows at noon the instant he fires his rocket the time on Mars--to him--jumps ahead 5 minutes. If he doesn't stop to visit Martha he knows her clock remains fixed at 12:05 indefinitely as he explores the rest of the Universe

Of course if he then fires his retros her clock jumps ahead to a much later reading depending on the distance he's come. It's classical relativity

The jumps of course are in Isaac's view only, not Al's nor Martha's
0 Replies

Butrflynet

1
Wed 5 Feb, 2014 05:00 pm
Have been following along as you folks struggle to define and discuss the theory.

Would this 23 page article on special relativity be of any aid to you guys? It has a glossary, examples and lots of charts and graphics that might help the discussion settle upon agreed upon defined terms to further your conjectures.

http://science.howstuffworks.com/science-vs-myth/everyday-myths/relativity.htm

To give you an idea of some of what it covers, here's the last page's summary:

Conclusion
SR deals with contractions and dilations that are not in agreement with our commonsense views of the universe. In fact, they almost appear ludicrous. Yet, there have been several observations that agree with the predictions of SR. So, until the theory is proved wrong or a simpler theory produces the same results, SR will maintain its position as the best theory out there.

There is no such thing as an absolute (completely stationary) frame of reference.
The laws of physics apply equally to all frames of reference.
The speed of light is constant in all frames of reference.
There is no simultaneity of events between separate frames of reference.
You are never too old to learn.

As you pursue a better understanding of SR, Do Not fall prey to these errant statements:

Time slows as speed increases. (Only when viewed by another frame of reference)
Objects shorten as speed increases. (Same as above)
SR can't handle acceleration. (Biggest misconception about SR)
Mass increases with speed. (Energy increases, not the rest mass)
Nothing can travel faster than the speed of light. Crossing the speed of light barrier from either a faster or a slower speed is disallowed.
The beauty in the theory of special relativity is that it gives us laws from which we can unite space and time and also energy and mass. Special relativity is definitely a thinking person's playground.
dalehileman

1
Wed 5 Feb, 2014 05:30 pm
@Butrflynet,
Thanks But for that rundown.

Quote:
You are never too old to learn.

Okay here's one commonsense argument that has long bothered me: Assuming a finite Megilah, if Martha's clock seems by Isaac's reckoning to be stuck at 12:05, what if he doesn't stop to chat with her but instead traverses the Universe, returning for a second trip but of course coming back from the opposite direction. Contrary to classical relativity (?) won't he find Al's clock, and Martha's of course, reading much (much, much) later

After all isn't our experiment exactly equivalent to one in which Isaac is stationary while the rest of the visible Universe swishes past at that enormous relative speed, everyone within range of communication agreeing with him that the Al's clock is indeed stuck at 12:00 and Martha's at 12:05

Or have I somehow established the existence of a stationary reference

Is it that even though he feels himself traveling in a straight line Isaac is actually circling with the same effect as reversing direction

Or is the commonsense view actually correct, that the time everywhere in the Universe with objects at rest with resp to one another actually is the same, that Marty's and Isaac's notions are somehow invalid
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Brandon9000

1
Wed 5 Feb, 2014 06:38 pm
@dalehileman,
dalehileman wrote:
...The supposed difference in the reading of a synchronized clock at a distant location based upon the observer's state of motion...

This response illustrates your problem exactly. A difference is the difference between two things, yet you don't indicate which two things it's the difference between. The difference in the reading of a single clock by two observers? If two observers have the instruments to read a single clock from their positions, next we would have to agree to when each observer reads it. If two observers with a relative speed read the same clock at the moment that a person standing behind the clock waves a white flag, they will agree as to what the clock says. Your basic problem is that you don't understand the theory and are making a series of poorly stated observations.
dalehileman

1
Wed 5 Feb, 2014 07:33 pm
@Brandon9000,
Quote:
you don't indicate which two things it's the difference between
Alas Bran I had thought it pretty obvious as the difference between the observers' clock readings and that of the distant clock

Quote:
The difference in the reading of a single clock by two observers?
In the case of my example yes. Thus at noon Isaac supposes Martha's clock to read 12:05, Marty 11:55

Quote:
If two observers have the instruments to read a single clock from their positions
They don't, their suppositions are based on a knowledge of relativity

Quote:
you don't understand the theory and are making a series of poorly stated observations.
Alas, alack
Brandon9000

1
Wed 5 Feb, 2014 08:32 pm
@dalehileman,
dalehileman wrote:

Quote:
you don't indicate which two things it's the difference between
Alas Bran I had thought it pretty obvious as the difference between the observers' clock readings and that of the distant clock

Quote:
The difference in the reading of a single clock by two observers?
In the case of my example yes. Thus at noon Isaac supposes Martha's clock to read 12:05, Marty 11:55

Quote:
If two observers have the instruments to read a single clock from their positions
They don't, their suppositions are based on a knowledge of relativity

Quote:
you don't understand the theory and are making a series of poorly stated observations.
Alas, alack

Your example is so saturated with misunderstanding stated unclearly and incompletely, that I would have to pore over your words for an hour to construct an explanation of what your errors are. The basic fact is that you don't understand this theory. You need to actually get a book on special relativity and read it from end to end.
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dalehileman

1
Thu 6 Feb, 2014 07:54 pm
@Butrflynet,
Thanks again But for that link. Scanning the article I was disappointed however that the notion of "time at a distance" wasn't discussed as such, and as I mentioned, was astounded I didn't find it Googling either

I therefore get the general impression that the concept is troubling or confusing to many, as with Bran in so many postings above. Part of the problem, again as I did mention above at least once, is the unspoken notion that the time everywhere in the Universe is the same for all relatively stationary objects, an idea very hard to abandon

I'd agree with one member who claims participation must have dropped radically. I can hardly imagine among an estimated 100,000 a2k users with visits of about 1000 a month, that nobody else is familiar with the concept
Brandon9000

1
Sat 8 Feb, 2014 02:49 am
@dalehileman,
dalehileman wrote:

Thanks again But for that link. Scanning the article I was disappointed however that the notion of "time at a distance" wasn't discussed as such, and as I mentioned, was astounded I didn't find it Googling either

I therefore get the general impression that the concept is troubling or confusing to many, as with Bran in so many postings above. Part of the problem, again as I did mention above at least once, is the unspoken notion that the time everywhere in the Universe is the same for all relatively stationary objects, an idea very hard to abandon

I'd agree with one member who claims participation must have dropped radically. I can hardly imagine among an estimated 100,000 a2k users with visits of about 1000 a month, that nobody else is familiar with the concept

Neither are you. There is no such thing ever discussed among people who understand the theory. You're simply wrong. Read a book.
contrex

1
Sat 8 Feb, 2014 03:09 am
@dalehileman,
dalehileman wrote:
I was disappointed however that the notion of "time at a distance" wasn't discussed as such, and as I mentioned, was astounded I didn't find it Googling either

I therefore get the general impression that the concept is troubling or confusing to many

It's nonsensical, that's the problem. You just aren't getting that.

rosborne979

1
Sat 8 Feb, 2014 12:02 pm
@dalehileman,
dalehileman wrote:
...that the time everywhere in the Universe is the same for all relatively stationary objects.

Can you explain what you mean by that.
dalehileman

1
Sat 8 Feb, 2014 01:00 pm
@contrex,
Quote:
It's nonsensical, that's the problem
Pulling a book at random from my bookcase "time-at-a-distance" is discussed in "Time and the Space Traveler" by L. Marder on pages 46, 113, 123, 126, and 130
0 Replies

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