Re: SR's velocity addition -- ANY Experimental Evidence?

From: Androcles (androc1es_at_nospamblueyonder.co.uk)
Date: 07/23/04 

Date: Fri, 23 Jul 2004 02:43:48 GMT

"Darrin Edwards" <edwards@nouce.trurl.bsd.uchicago.edu> wrote in message
news:slrncg0o9p.a6i.edwards@trurl.bsd.uchicago.edu...
| In article <GvDLc.5284$FD1.51990683@news-text.cableinet.net>, Androcles
wrote:
| >
| > "Darrin Edwards" <edwards@nouce.trurl.bsd.uchicago.edu> wrote in message
| > news:slrncftvgt.tfi.edwards@trurl.bsd.uchicago.edu...
| >| In article <bTsLc.4695$PY3.46950542@news-text.cableinet.net>, Androcles
| > wrote:
| >| > "Darrin Edwards" <edwards@nouce.trurl.bsd.uchicago.edu> wrote in
message
| >| > news:slrncfrf5f.hie.edwards@trurl.bsd.uchicago.edu...
| >| >| In article <ctaLc.3976$Sn2.39699610@news-text.cableinet.net>,
Androcles
| >| >| wrote:
| >| >| > Time is not a vector,
| >| >|
| >| >| Sure it is, it's modeled as a one-dimensional vector.
| >| >|
| >| >| > it has no inverse.
| >| >|
| >| >| Cf. the English word "ago".
| >| >|
| >| >| > You can return from where you were by travelling a distance 1 mile
| >| >| > and returning a distance of -1 mile. When you are able to return
to
| >| >| > when you were by waiting one second and then unwaiting -1 second
| >| >| > then you can call time a vector, and not before.
| >| >|
| >| >| That's because of physics.
| >| >
| >| > Yes, and physics is the topic of discussion.
| >|
| >| And in physics, time is modelled as a (one-dimensional) vector.
| >
| > No sensible physicist would seriously make such a gross error
| > as travelling backwards in time. If you know of one, he's actually a
kook.
|
| Another red herring. One doesn't need to be a "time traveler" to be
| able to understand the concepts embodied by the English words "ago" and
| "before".
|
| >| >| Mathematically, time is modelled as a
| >| >| one-dimensional vector in both Newtonian mechanics and SR.
| >| >
| >| > Mathematics is Art.
| >| > Scientists and Engineers use math as a useful tool, but that doesn't
| >| > entitle
| >| > anyone to pretend they can convert time into distance, mass into time
or
| >| > distance into mass, even if it possible to do so mathematically. GIGO
| >| > applies.
| >|
| >| I don't need to "pretend" I can convert time into distance; every day
| >| I convert a half hour of my time into the roughly two miles between my
| >| home + workplace by the simple expedient of walking at roughly four
| >| miles an hour.
| >
| > When you can reduce the time it takes you to get there to zero by
walking at
| > 186,000 miles per second, arriving instantly, let me know.
|
| Eh? What on earth are you trying to say here? x=vt is only valid if
| v=c? "GIGO" indeed.
|
| > When you can go
| > home again, arriving where you were when you were, you can call time a
| > vector. Until then, it isn't.
|
| That argument is exactly equivalent to, and no more valid than,
| claiming that positions can't be modelled by (three-dimensional)
| vectors, since you can't travel a certain distance and return to your
| starting point in zero time.
|
| >| But none of what you said has anything to do with time
| >| being modeled as a (one-dimensional) vector.
| >|
| >| Are you familiar with the definition of "vector"?
| > Yes. You can find references to it all over the internet. Look it up,
| > vectors have inverses.
|
| If A will happen an hour from now, and B will happen an hour before A,
| then B is happening... now! That's all that's meant by "inverse"
| here, no need to pull in "time traveler" red herrings.
|
| >| If so, what
| >| specific property of a (one-dimensional) vector space are you claiming
| >| is _not_ possessed by time?
| >
| > No inverse. I've told you that already.
|
| Yes, inverses. Anything else?
|
| >| Some hints:
| > I don't need any fucking hints, or stupidity about time being a vector.
|
| >| you can add two times together to get another time, and
| >| you can multiply a time by a number to get another time. As for the
| >| "unwaiting -1 second" red herring above, if someone says their plane
| >| leaves in five hours, and that they have to leave home for the airport
| >| three hours _before_ that, is anyone really mystified by the conclusion
| >| that they have 5-3=2 hours left to pack?
| >
| > It's 6:00 pm, the plane leaves at 5:00 pm. Go and board the plane, you
| > have -1 hour to do so.
|
| That's correct, 5-6 = -1. My plane did indeed leave an hour _ago_.
| Sucks to be me, but then, how on earth could we have reached that
| conclusion without making use of the additive inverse of 6 hours?
|
| > Since time is a vector, -1 hour should be no trouble to you.
|
| It's certainly no trouble to understand the _physics_ of the
| situation, i.e. that my plane left an hour _ago_. Since you got the
| right answer as well here, it's obviously "no trouble to you" either.
|
| > If there are any red herrings around here, it is 5-3 = 2 when the 5
| > exists in the future.
| > Do so when it is in the past and time will be a vector.
|
| Um, sure, now the person is sitting happily on the plane just as it
| takes off. They fondly look back on the time five hours _ago_ when
| they started packing, and on the time three hours _ago_ when they left
| home. Hmm, -3 - -5 = 2 hours spent packing. Again, "is anyone really
| mystified by this conclusion"?

Yes, since you were not on the plane. It left hours ago.

Vector to the airport. No problem. Vector home again. No problem. Vector to
tomorrow (avoid it if you can). Vector to yesterday. No way.
Of course ordinary language uses terms such as "ago". But you have no
control of yesterday, and you cannot go there. "Vector" is a precise
mathematical term, described by axioms. Force is a vector, you can pull the
other way. Time is not a vector, you cannot go back in time. Now, since you
prefer to use ordinary English in your vague definitions, and I prefer
precise mathematical descriptions, there can be no meeting of the minds.
Caio.
*plonk*
Androcles

| --
| Cheers,
| Darrin

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