Rocksolid Light

Welcome to novaBBS (click a section below)

mail  files  register  newsreader  groups  login

Message-ID:  

I find you lack of faith in the forth dithturbing. -- Darse ("Darth") Vader


tech / sci.electronics.design / Re: The Twins Paradox in Relativity

SubjectAuthor
* The Twins Paradox in RelativityJoe Gwinn
+* Re: The Twins Paradox in RelativityJeff Layman
|+- Re: The Twins Paradox in RelativitySylvia Else
|+* Re: The Twins Paradox in RelativityPhil Hobbs
||+* Re: The Twins Paradox in Relativitycorvid
|||`* Re: The Twins Paradox in RelativityPhil Hobbs
||| `* Re: The Twins Paradox in Relativitycorvid
|||  +- Re: The Twins Paradox in RelativityPhil Hobbs
|||  `* Re: The Twins Paradox in RelativityRichD
|||   `- Re: The Twins Paradox in RelativityPhil Hobbs
||+- Re: The Twins Paradox in RelativityDimiter_Popoff
||+* Re: The Twins Paradox in RelativityClifford Heath
|||`* Re: The Twins Paradox in RelativityPhil Hobbs
||| `* Re: The Twins Paradox in RelativityClifford Heath
|||  `- Re: The Twins Paradox in RelativityPhil Hobbs
||`* Re: The Twins Paradox in RelativityJohn Robertson
|| +- Re: The Twins Paradox in RelativityPhil Hobbs
|| `- Re: The Twins Paradox in RelativityPhil Hobbs
|`- Re: The Twins Paradox in RelativityMartin Brown
+* Re: The Twins Paradox in RelativityDimiter_Popoff
|`* Re: The Twins Paradox in RelativityMartin Brown
| +* Re: The Twins Paradox in RelativityDimiter_Popoff
| |+* Re: The Twins Paradox in RelativityMartin Brown
| ||`- Re: The Twins Paradox in RelativityDimiter_Popoff
| |`- Re: The Twins Paradox in RelativityClive Arthur
| `* Re: The Twins Paradox in RelativityKevin Aylward
|  `- Re: The Twins Paradox in RelativityClive Arthur
`- Re: The Twins Paradox in RelativityKevin Aylward

Pages:12
The Twins Paradox in Relativity

<m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96844&group=sci.electronics.design#96844

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!buffer1.nntp.dca1.giganews.com!news.giganews.com.POSTED!not-for-mail
NNTP-Posting-Date: Sat, 14 May 2022 16:35:44 -0500
From: joegw...@comcast.net (Joe Gwinn)
Newsgroups: sci.electronics.design
Subject: The Twins Paradox in Relativity
Date: Sat, 14 May 2022 17:35:44 -0400
Message-ID: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
User-Agent: ForteAgent/8.00.32.1272
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Lines: 5
X-Usenet-Provider: http://www.giganews.com
X-Trace: sv3-eoA8o8E97vAwq2Y1zKteO4OhcsJr/kmlhAd7/68dQIzlpucklYEXliql+7FhjFXgs9Vl/SKrhPGeVD/!RHUkOFCJJpAJowfH+VNnGdZqPdw1ox4P5ktHen/Htf4QyPS9YTSlhzt8R3Cq4IiA/RCYLuY=
X-Complaints-To: abuse@giganews.com
X-DMCA-Notifications: http://www.giganews.com/info/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 1112
 by: Joe Gwinn - Sat, 14 May 2022 21:35 UTC

It turns out there is a long history, with many parallel explanations:

..<https://en.wikipedia.org/wiki/Twin_paradox>

Joe Gwinn

Re: The Twins Paradox in Relativity

<t5qekr$hnd$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96889&group=sci.electronics.design#96889

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: jmlay...@invalid.invalid (Jeff Layman)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Sun, 15 May 2022 09:46:18 +0100
Organization: A noiseless patient Spider
Lines: 33
Message-ID: <t5qekr$hnd$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Sun, 15 May 2022 08:46:19 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="cbe7b1f544115572bf8ae3876dff0f1f";
logging-data="18157"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18uJCe6dIwQI6SyIMXxTLbewGYfXdGZ4DI="
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
Thunderbird/91.8.1
Cancel-Lock: sha1:XwNFAqJ0RM7oYaZ/rCUHPgCNd/I=
In-Reply-To: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
Content-Language: en-GB
 by: Jeff Layman - Sun, 15 May 2022 08:46 UTC

On 14/05/2022 22:35, Joe Gwinn wrote:
> It turns out there is a long history, with many parallel explanations:
>
> .<https://en.wikipedia.org/wiki/Twin_paradox>

It can be expanded to the Triplets Paradox, for example
<http://www.mysearch.org.uk/website1/html/251.Triplets.html>

SRT is well above me, I'm afraid. Some of the explanation of the Twins
Paradox refers to the twins' clocks transmitting their time to the other
twin (the clock signal is transmitted at the speed of light). Even
allowing for the travelling twin's speed when approaching the speed of
light, and the relativistic effect it has on each clock's perceived
time, as the travelling twin's speed doesn't exceed that speed, each
twin will, eventually, receive the clock time of the other.

But what happens with the Triplet Paradox where the moving triplets are
accelerating away from each other? Once they've "exceeded" C in relation
to each other, although they can receive the stationary triplet's clock
reading (and he can receive theirs), can one moving triplet still
receive the other moving triplet's clock signal? If there is such a
moment when they can no longer receive each other's signal, when they
finally stop moving away and start moving towards each other again, will
there be a moment when they suddenly start receiving that "missing"
clock signal as they catch up with it (or perhaps it catches up with
them)? Will there be a specific moment when they not only receive a
missing clock time, but coincidentally receive the "accurate" time as
transmitted by the other moving triplet, so appear to be receiving two
different clock readings at the same time?

--

Jeff

Re: The Twins Paradox in Relativity

<t5qmq2$78i$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96897&group=sci.electronics.design#96897

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: dp...@tgi-sci.com (Dimiter_Popoff)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Sun, 15 May 2022 14:05:36 +0300
Organization: TGI
Lines: 29
Message-ID: <t5qmq2$78i$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
Reply-To: dp@tgi-sci.com
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Sun, 15 May 2022 11:05:38 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="dad7784848d7c11c376dc31865911f17";
logging-data="7442"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/aQcyGfRRPQrwyQtS6/N5N/78nXLt0eZU="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:da+h+iGqPkrYtLhxRaDO8sy3Wto=
In-Reply-To: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
Content-Language: en-US
 by: Dimiter_Popoff - Sun, 15 May 2022 11:05 UTC

On 5/15/2022 0:35, Joe Gwinn wrote:
> It turns out there is a long history, with many parallel explanations:
>
> .<https://en.wikipedia.org/wiki/Twin_paradox>
>
> Joe Gwinn

I am not a physicist but like many of us here I have been banging my
head into various technical problems so I am used to see when some
claim is somewhat questionable.
It's been years since I have read Einstein's papers but I remember
an example he gives, that with a train and a periodically flashing
light on it.
Obviously if the train is moving away from the observer because of the
fixed speed of light the period will seem somewhat longer to the
observer.
What is not addressed by this simple example is the case when the train
moves towards the observer - in which case obviously the period
will seem shorter to the observer.
A way to think of all that in terms obvious to most of us here
is that our reality is a state machine clocked (IIRC there was some
minimum time defined by Max Planck, could be the clock period) by
some clock; what we perceive as time is the resulting change of
states.
While this is a simplified and probably naive model it does
explain the train-flashing-light-period dependence on direction.
And it explains why clocks at the equator and on the poles run
the same without involving gravity.

Re: The Twins Paradox in Relativity

<t5tia2$6m9$1@gioia.aioe.org>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96963&group=sci.electronics.design#96963

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!aioe.org!41edQ3YjPRN8eZ1dw7PDcA.user.46.165.242.75.POSTED!not-for-mail
From: '''newsp...@nonad.co.uk (Martin Brown)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 14:07:13 +0100
Organization: Aioe.org NNTP Server
Message-ID: <t5tia2$6m9$1@gioia.aioe.org>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: gioia.aioe.org; logging-data="6857"; posting-host="41edQ3YjPRN8eZ1dw7PDcA.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org";
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Content-Language: en-GB
X-Notice: Filtered by postfilter v. 0.9.2
 by: Martin Brown - Mon, 16 May 2022 13:07 UTC

On 15/05/2022 12:05, Dimiter_Popoff wrote:
> On 5/15/2022 0:35, Joe Gwinn wrote:
>> It turns out there is a long history, with many parallel explanations:
>>
>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>
>> Joe Gwinn
>
> And it explains why clocks at the equator and on the poles run
> the same without involving gravity.

Actually they don't.

One of Einstein's minor errors in his 1905 paper on special relativity
was to predict how much slower a clock at the equator would tick when
compared to one at the pole (due to the extra rotational speed of a
clock at the equator). Every now and then someone points it out... eg

https://physicstoday.scitation.org/doi/10.1063/1.1897562#

They only run at the same speed when *both* the GR and SR corrections
are applied simultaneously and only then at mean sea level.

It is hard to get your head round but everybody's clock ticks at a
different speed. Your head ages marginally more quickly than your feet.

The best clocks in the world at NIST are now sensitive and stable enough
to detect a vertical shift of about 30cm or a foot in old money.

https://www.nist.gov/news-events/news/2010/09/nist-pair-aluminum-atomic-clocks-reveal-einsteins-relativity-personal-scale

This isn't a bad introduction by Brian Cox for BBC science series.

https://www.bbc.co.uk/iplayer/episode/m000x9v4/brian-coxs-adventures-in-space-and-time-series-1-4-what-is-time

(you might have to spoof a UK address to see it)

--
Regards,
Martin Brown

Re: The Twins Paradox in Relativity

<jef1m8FrclcU1@mid.individual.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96964&group=sci.electronics.design#96964

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder8.news.weretis.net!news.szaf.org!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: syl...@email.invalid (Sylvia Else)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 23:25:28 +1000
Lines: 11
Message-ID: <jef1m8FrclcU1@mid.individual.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-Trace: individual.net NF4JXVQppjq5vEM8H1+VEwgKbvdOscZP7Vg2L7XjLt+7oAo8rd
Cancel-Lock: sha1:Le2MuUvszHqDky2wTLxLhb6VjpQ=
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Content-Language: en-GB
In-Reply-To: <t5qekr$hnd$1@dont-email.me>
 by: Sylvia Else - Mon, 16 May 2022 13:25 UTC

On 15-May-22 6:46 pm, Jeff Layman wrote:

> But what happens with the Triplet Paradox where the moving triplets are
> accelerating away from each other? Once they've "exceeded" C in relation
> to each other, <snip>

That doesn't happen.

Sylvia.

Re: The Twins Paradox in Relativity

<t5tk43$ldi$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96965&group=sci.electronics.design#96965

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: dp...@tgi-sci.com (Dimiter_Popoff)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 16:38:10 +0300
Organization: TGI
Lines: 52
Message-ID: <t5tk43$ldi$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
Reply-To: dp@tgi-sci.com
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Mon, 16 May 2022 13:38:11 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="026ca8177fb325bc1ed4612b6a5024b7";
logging-data="21938"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/HrJ2Glenlo3hrm5vSa2ZUDhKVb+wTnng="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:GGaNcXjnc2PP9toC8gFiWsalF0I=
In-Reply-To: <t5tia2$6m9$1@gioia.aioe.org>
Content-Language: en-US
 by: Dimiter_Popoff - Mon, 16 May 2022 13:38 UTC

On 5/16/2022 16:07, Martin Brown wrote:
> On 15/05/2022 12:05, Dimiter_Popoff wrote:
>> On 5/15/2022 0:35, Joe Gwinn wrote:
>>> It turns out there is a long history, with many parallel explanations:
>>>
>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>>
>>> Joe Gwinn
>>
>> And it explains why clocks at the equator and on the poles run
>> the same without involving gravity.
>
> Actually they don't.
>
> One of Einstein's minor errors in his 1905 paper on special relativity
> was to predict how much slower a clock at the equator would tick when
> compared to one at the pole (due to the extra rotational speed of a
> clock at the equator). Every now and then someone points it out... eg
>
> https://physicstoday.scitation.org/doi/10.1063/1.1897562#
>
> They only run at the same speed when *both* the GR and SR corrections
> are applied simultaneously and only then at mean sea level.
>
> It is hard to get your head round but everybody's clock ticks at a
> different speed. Your head ages marginally more quickly than your feet.
>
> The best clocks in the world at NIST are now sensitive and stable enough
> to detect a vertical shift of about 30cm or a foot in old money.
>
> https://www.nist.gov/news-events/news/2010/09/nist-pair-aluminum-atomic-clocks-reveal-einsteins-relativity-personal-scale
>
>
> This isn't a bad introduction by Brian Cox for BBC science series.
>
> https://www.bbc.co.uk/iplayer/episode/m000x9v4/brian-coxs-adventures-in-space-and-time-series-1-4-what-is-time
>
>
> (you might have to spoof a UK address to see it)
>

I have been digging into physics just as much as it takes to do what I
do so me being naive with that sort of thing is no surprise. I am
vaguely aware of what your references say, I think I may have read some
of these some time ago.
What I don't get though is the flashing light on the train thing.
Looks obvious to me that the observed period depends on the movement
direction (assuming gravity is constant, i.e. it is no factor).
In fact this should be easily measurable (not that I would go into
it, just wondering if you or someone else has an explanation, I am
not the "out there to challenge the science" type, more the "curious
until things get clarified for me" sort).

Re: The Twins Paradox in Relativity

<t5tm5o$54p$1@gioia.aioe.org>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96968&group=sci.electronics.design#96968

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!aioe.org!41edQ3YjPRN8eZ1dw7PDcA.user.46.165.242.75.POSTED!not-for-mail
From: '''newsp...@nonad.co.uk (Martin Brown)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 15:13:11 +0100
Organization: Aioe.org NNTP Server
Message-ID: <t5tm5o$54p$1@gioia.aioe.org>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
<t5tk43$ldi$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: gioia.aioe.org; logging-data="5273"; posting-host="41edQ3YjPRN8eZ1dw7PDcA.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org";
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Content-Language: en-GB
X-Notice: Filtered by postfilter v. 0.9.2
 by: Martin Brown - Mon, 16 May 2022 14:13 UTC

On 16/05/2022 14:38, Dimiter_Popoff wrote:

> I have been digging into physics just as much as it takes to do what I
> do so me being naive with that sort of thing is no surprise. I am
> vaguely aware of what your references say, I think I may have read some
> of these some time ago.

> What I don't get though is the flashing light on the train thing.
> Looks obvious to me that the observed period depends on the movement
> direction (assuming gravity is constant, i.e. it is no factor).

The bit you are missing is that to be able to meaningfully compare times
between two different moving objects they *have* to be at the same
location. That means a round trip back to the stay at home.

> In fact this should be easily measurable (not that I would go into
> it, just wondering if you or someone else has an explanation, I am
> not the "out there to challenge the science" type, more the "curious
> until things get clarified for me" sort).

One of the classic illustrations is to draw a world lines diagram for
bleep who stays put and booster who goes off at 4c/5 (3,4,5 triangle).

This illustration says it more clearly than words ever can. It was a
diagram of this sort that convinced me to give up on common sense where
relativity was concerned and trust the mathematics.

<https://www.google.com/url?sa=i&url=https%3A%2F%2Faapt.scitation.org%2Fdoi%2F10.1119%2F1.4947152&psig=AOvVaw2kQVy1xGR-cIehmwjR9R5y&ust=1652796475815000&source=images&cd=vfe&ved=0CAkQjRxqFwoTCLialeiY5PcCFQAAAAAdAAAAABAE>

It points to this article (behind a paywall:( )
https://aapt.scitation.org/doi/10.1119/1.4947152

Be a miracle if that works so Google keywords
"world lines signal twin paradox illustration"

--
Regards,
Martin Brown

Re: The Twins Paradox in Relativity

<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96969&group=sci.electronics.design#96969

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 10:18:05 -0400
Organization: A noiseless patient Spider
Lines: 79
Message-ID: <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: reader02.eternal-september.org; posting-host="d5c885e14cc55ba5da8e14edb4b8ff7e";
logging-data="9933"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19NFCApZfxbDycNPdeWjjlE"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
Thunderbird/68.0
Cancel-Lock: sha1:28y7Xeqa4Oq+cx/gdXlHSvsQM/8=
In-Reply-To: <t5qekr$hnd$1@dont-email.me>
 by: Phil Hobbs - Mon, 16 May 2022 14:18 UTC

Jeff Layman wrote:
> On 14/05/2022 22:35, Joe Gwinn wrote:
>> It turns out there is a long history, with many parallel explanations:
>>
>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>
> It can be expanded to the Triplets Paradox, for example
> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>
> SRT is well above me, I'm afraid. Some of the explanation of the Twins
> Paradox refers to the twins' clocks transmitting their time to the other
> twin (the clock signal is transmitted at the speed of light). Even
> allowing for the travelling twin's speed when approaching the speed of
> light, and the relativistic effect it has on each clock's perceived
> time, as the travelling twin's speed doesn't exceed that speed, each
> twin will, eventually, receive the clock time of the other.
>
> But what happens with the Triplet Paradox where the moving triplets are
> accelerating away from each other? Once they've "exceeded" C in relation
> to each other, although they can receive the stationary triplet's clock
> reading (and he can receive theirs), can one moving triplet still
> receive the other moving triplet's clock signal? If there is such a
> moment when they can no longer receive each other's signal, when they
> finally stop moving away and start moving towards each other again, will
> there be a moment when they suddenly start receiving that "missing"
> clock signal as they catch up with it (or perhaps it catches up with
> them)? Will there be a specific moment when they not only receive a
> missing clock time, but coincidentally receive the "accurate" time as
> transmitted by the other moving triplet, so appear to be receiving two
> different clock readings at the same time?
>

If you shine your laser pointer at two points 180 degrees apart in the
sky, the relative speed of the light pulses in your frame of reference
is 2c. No paradox is involved.

Also, there's no simultaneity between separated objects moving at
different speeds. The relativistic garage illustrates this.

Say you have a 1927 Bugatti Type 41, which is 252 inches long. Your
garage is the standard 20 feed (240 inches) long, and has a very fast
automatically-controlled door at each end. The doors are designed to
open and close automatically to allow the car to enter and leave.

Because the Bugatti is so fast, you drive towards the open end of the
garage at 0.5c. You measure the length of the garage as

240 inches * sqrt(1-0.5**2) = 207.8 inches.

The hood of the car passes through the open door, then the closed door
opens before the back bumper has passed through the doorway. No
collision occurs, because the second door opens before the first one closes.

Your spouse, waiting for you to come home from your drive, measures the
length of the car as

252 inches * sqrt(1-0.5**2) = 218.2 inches.

The car fits into the garage, so as it enters, the first door closes
before the second door opens. Once again no collision occurs, because
the car is shorter than the garage.

The math works out fine in both English and metric, and no paradoxes are
involved.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<t5tqnl$eg5$1@gioia.aioe.org>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96984&group=sci.electronics.design#96984

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!aioe.org!xUOiStaTX9GQDNXPji0+sg.user.46.165.242.75.POSTED!not-for-mail
From: bl...@ckb.ird (corvid)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 08:31:00 -0700
Organization: The 27 Club
Message-ID: <t5tqnl$eg5$1@gioia.aioe.org>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: gioia.aioe.org; logging-data="14853"; posting-host="xUOiStaTX9GQDNXPji0+sg.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org";
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
Gecko/20100101 Thunderbird/91.9.0
X-Notice: Filtered by postfilter v. 0.9.2
Content-Language: en-US
 by: corvid - Mon, 16 May 2022 15:31 UTC

On 5/16/22 07:18, Phil Hobbs wrote:
> Jeff Layman wrote:
>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>> It turns out there is a long history, with many parallel
>>> explanations:
>>>
>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>
>> It can be expanded to the Triplets Paradox, for example
>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>
>> SRT is well above me, I'm afraid. Some of the explanation of the
>> Twins Paradox refers to the twins' clocks transmitting their time
>> to the other twin (the clock signal is transmitted at the speed of
>> light). Even allowing for the travelling twin's speed when
>> approaching the speed of light, and the relativistic effect it has
>> on each clock's perceived time, as the travelling twin's speed
>> doesn't exceed that speed, each twin will, eventually, receive the
>> clock time of the other.
>>
>> But what happens with the Triplet Paradox where the moving triplets
>> are accelerating away from each other? Once they've "exceeded" C
>> in relation to each other, although they can receive the stationary
>> triplet's clock reading (and he can receive theirs), can one
>> moving triplet still receive the other moving triplet's clock
>> signal? If there is such a moment when they can no longer receive
>> each other's signal, when they finally stop moving away and start
>> moving towards each other again, will there be a moment when they
>> suddenly start receiving that "missing" clock signal as they catch
>> up with it (or perhaps it catches up with them)? Will there be a
>> specific moment when they not only receive a missing clock time,
>> but coincidentally receive the "accurate" time as transmitted by
>> the other moving triplet, so appear to be receiving two different
>> clock readings at the same time?
>>
>
> If you shine your laser pointer at two points 180 degrees apart in
> the sky, the relative speed of the light pulses in your frame of
> reference is 2c. No paradox is involved.
>
> Also, there's no simultaneity between separated objects moving at
> different speeds. The relativistic garage illustrates this.
>
> Say you have a 1927 Bugatti Type 41, which is 252 inches long. Your
> garage is the standard 20 feed (240 inches) long, and has a very
> fast automatically-controlled door at each end. The doors are
> designed to open and close automatically to allow the car to enter
> and leave.
>
> Because the Bugatti is so fast, you drive towards the open end of the
> garage at 0.5c. You measure the length of the garage as
>
> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>
> The hood of the car passes through the open door, then the closed
> door opens before the back bumper has passed through the doorway. No
> collision occurs, because the second door opens before the first one
> closes.
>
> Your spouse, waiting for you to come home from your drive, measures
> the length of the car as
>
> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>
> The car fits into the garage, so as it enters, the first door closes
> before the second door opens. Once again no collision occurs,
> because the car is shorter than the garage.
>
> The math works out fine in both English and metric, and no paradoxes
> are involved.
>
> Cheers
>
> Phil Hobbs

But, but... the bottom of the tires are in contact with the garage
floor. Shouldn't that anchor the Bugatti and garage into the same frame?

Re: The Twins Paradox in Relativity

<t5tsbb$o80$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96986&group=sci.electronics.design#96986

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: dp...@tgi-sci.com (Dimiter_Popoff)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 18:58:35 +0300
Organization: TGI
Lines: 51
Message-ID: <t5tsbb$o80$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
Reply-To: dp@tgi-sci.com
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Mon, 16 May 2022 15:58:35 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="026ca8177fb325bc1ed4612b6a5024b7";
logging-data="24832"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+4G8ibRyag2Okmo44SeoK2FdbCeIZexQs="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:AnA7E5KglZnBOx34z+29zVRdWZw=
In-Reply-To: <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
Content-Language: en-US
 by: Dimiter_Popoff - Mon, 16 May 2022 15:58 UTC

On 5/16/2022 17:18, Phil Hobbs wrote:
> Jeff Layman wrote:
>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>> It turns out there is a long history, with many parallel explanations:
>>>
>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>
>> It can be expanded to the Triplets Paradox, for example
>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>
>> SRT is well above me, I'm afraid. Some of the explanation of the Twins
>> Paradox refers to the twins' clocks transmitting their time to the
>> other twin (the clock signal is transmitted at the speed of light).
>> Even allowing for the travelling twin's speed when approaching the
>> speed of light, and the relativistic effect it has on each clock's
>> perceived time, as the travelling twin's speed doesn't exceed that
>> speed, each twin will, eventually, receive the clock time of the other.
>>
>> But what happens with the Triplet Paradox where the moving triplets
>> are accelerating away from each other? Once they've "exceeded" C in
>> relation to each other, although they can receive the stationary
>> triplet's clock reading (and he can receive theirs), can one moving
>> triplet still receive the other moving triplet's clock signal? If
>> there is such a moment when they can no longer receive each other's
>> signal, when they finally stop moving away and start moving towards
>> each other again, will there be a moment when they suddenly start
>> receiving that "missing" clock signal as they catch up with it (or
>> perhaps it catches up with them)? Will there be a specific moment when
>> they not only receive a missing clock time, but coincidentally receive
>> the "accurate" time as transmitted by the other moving triplet, so
>> appear to be receiving two different clock readings at the same time?
>>
>
> If you shine your laser pointer at two points 180 degrees apart in the
> sky, the relative speed of the light pulses in your frame of reference
> is 2c.  No paradox is involved.

This is obvious enough. I refer to the case where the laser pointer is
moving towards us; no RTT involved, we just measure the period at which
it flashes. Since the light speed is always c and every next flash will
have less distance to travel until it reaches us it seems obvious
we will see a period shorter than it is for an observer moving together
with the pointer. And vice versa, if the pointer moves away from us
each next flash will have more distance to travel at c to reach us
so the period we will see will be longer than at the pointer (the
latter being the example Einstein gives in some of the papers, IIRC).
Should not be too hard to test experimentally nowadays (the direction
dependence, that is). At the moment I can't see how the period of an
approaching pointer will be longer for the observer.
I'll better switch to doing something useful, it is not that I don't
have enough to do :-).

Re: The Twins Paradox in Relativity

<t5tt2k$v24$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96987&group=sci.electronics.design#96987

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: dp...@tgi-sci.com (Dimiter_Popoff)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 19:10:59 +0300
Organization: TGI
Lines: 47
Message-ID: <t5tt2k$v24$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
<t5tk43$ldi$1@dont-email.me> <t5tm5o$54p$1@gioia.aioe.org>
Reply-To: dp@tgi-sci.com
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Date: Mon, 16 May 2022 16:11:00 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="026ca8177fb325bc1ed4612b6a5024b7";
logging-data="31812"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+yX+xhxd+fMfsv4pJVA4q1uhbmZu5JAYs="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:MX2SIBP3rlfWslpdAFJ070oMzQQ=
In-Reply-To: <t5tm5o$54p$1@gioia.aioe.org>
Content-Language: en-US
 by: Dimiter_Popoff - Mon, 16 May 2022 16:10 UTC

On 5/16/2022 17:13, Martin Brown wrote:
> On 16/05/2022 14:38, Dimiter_Popoff wrote:
>
>> I have been digging into physics just as much as it takes to do what I
>> do so me being naive with that sort of thing is no surprise. I am
>> vaguely aware of what your references say, I think I may have read some
>> of these some time ago.
>
>> What I don't get though is the flashing light on the train thing.
>> Looks obvious to me that the observed period depends on the movement
>> direction (assuming gravity is constant, i.e. it is no factor).
>
> The bit you are missing is that to be able to meaningfully compare times
> between two different moving objects they *have* to be at the same
> location. That means a round trip back to the stay at home.
>
>> In fact this should be easily measurable (not that I would go into
>> it, just wondering if you or someone else has an explanation, I am
>> not the "out there to challenge the science" type, more the "curious
>> until things get clarified for me" sort).
>
> One of the classic illustrations is to draw a world lines diagram for
> bleep who stays put and booster who goes off at  4c/5 (3,4,5 triangle).
>
> This illustration says it more clearly than words ever can. It was a
> diagram of this sort that convinced me to give up on common sense where
> relativity was concerned and trust the mathematics.
>
> <https://www.google.com/url?sa=i&url=https%3A%2F%2Faapt.scitation.org%2Fdoi%2F10.1119%2F1.4947152&psig=AOvVaw2kQVy1xGR-cIehmwjR9R5y&ust=1652796475815000&source=images&cd=vfe&ved=0CAkQjRxqFwoTCLialeiY5PcCFQAAAAAdAAAAABAE>
>
>
> It points to this article (behind a paywall:( )
> https://aapt.scitation.org/doi/10.1119/1.4947152
>
> Be a miracle if that works so Google keywords
> "world lines signal twin paradox illustration"
>

I am not talking about the "twin paradox", I had not heard the
phrase until this post (or did not remember I had). It involves
acceleration so things get more complex.
I refer only to the blinking object moving towards us and away from
us, no acceleration (I put that into more detail in my post to
Phil).
I'll try to switch to doing useful work now though. Thanks for
the links and explanations, once I get bugged again I'll probably
be heard of :-).

Re: The Twins Paradox in Relativity

<930a2a0a-712f-98dd-0576-108b21f8e79e@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=96998&group=sci.electronics.design#96998

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 16:26:15 -0400
Organization: A noiseless patient Spider
Lines: 99
Message-ID: <930a2a0a-712f-98dd-0576-108b21f8e79e@electrooptical.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<t5tqnl$eg5$1@gioia.aioe.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: reader02.eternal-september.org; posting-host="a6d3ca55f88ebed4582d217d4d5bd61a";
logging-data="20849"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18e0Cw3j4QUdij3uRwjzSer"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:YXwIhQZtqZZHixJgJlElJuH29UM=
In-Reply-To: <t5tqnl$eg5$1@gioia.aioe.org>
 by: Phil Hobbs - Mon, 16 May 2022 20:26 UTC

corvid wrote:
> On 5/16/22 07:18, Phil Hobbs wrote:
>> Jeff Layman wrote:
>>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>>> It turns out there is a long history, with many parallel
>>>> explanations:
>>>>
>>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>>
>>> It can be expanded to the Triplets Paradox, for example
>>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>>
>>> SRT is well above me, I'm afraid. Some of the explanation of the
>>> Twins Paradox refers to the twins' clocks transmitting their
>>> time to the other twin (the clock signal is transmitted at the
>>> speed of light). Even allowing for the travelling twin's speed
>>> when approaching the speed of light, and the relativistic effect
>>> it has on each clock's perceived time, as the travelling twin's
>>> speed doesn't exceed that speed, each twin will, eventually,
>>> receive the clock time of the other.
>>>
>>> But what happens with the Triplet Paradox where the moving
>>> triplets are accelerating away from each other? Once they've
>>> "exceeded" C in relation to each other, although they can receive
>>> the stationary triplet's clock reading (and he can receive
>>> theirs), can one moving triplet still receive the other moving
>>> triplet's clock signal? If there is such a moment when they can
>>> no longer receive each other's signal, when they finally stop
>>> moving away and start moving towards each other again, will there
>>> be a moment when they suddenly start receiving that "missing"
>>> clock signal as they catch up with it (or perhaps it catches up
>>> with them)? Will there be a specific moment when they not only
>>> receive a missing clock time, but coincidentally receive the
>>> "accurate" time as transmitted by the other moving triplet, so
>>> appear to be receiving two different clock readings at the same
>>> time?
>>>
>>
>> If you shine your laser pointer at two points 180 degrees apart in
>> the sky, the relative speed of the light pulses in your frame of
>> reference is 2c. No paradox is involved.
>>
>> Also, there's no simultaneity between separated objects moving at
>> different speeds. The relativistic garage illustrates this.
>>
>> Say you have a 1927 Bugatti Type 41, which is 252 inches long.
>> Your garage is the standard 20 feed (240 inches) long, and has a
>> very fast automatically-controlled door at each end. The doors
>> are designed to open and close automatically to allow the car to
>> enter and leave.
>>
>> Because the Bugatti is so fast, you drive towards the open end of
>> the garage at 0.5c. You measure the length of the garage as
>>
>> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>>
>> The hood of the car passes through the open door, then the closed
>> door opens before the back bumper has passed through the doorway.
>> No collision occurs, because the second door opens before the first
>> one closes.
>>
>> Your spouse, waiting for you to come home from your drive,
>> measures the length of the car as
>>
>> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>>
>> The car fits into the garage, so as it enters, the first door
>> closes before the second door opens. Once again no collision
>> occurs, because the car is shorter than the garage.
>>
>> The math works out fine in both English and metric, and no
>> paradoxes are involved.
>>
>> Cheers
>>
>> Phil Hobbs
>
> But, but... the bottom of the tires are in contact with the garage
> floor. Shouldn't that anchor the Bugatti and garage into the same
> frame?

And the pistons are going up and down pretty good too. ;)

Just stick with the front and rear bumpers for present purposes.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<t5udl7$1bh6$1@gioia.aioe.org>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97000&group=sci.electronics.design#97000

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!aioe.org!xUOiStaTX9GQDNXPji0+sg.user.46.165.242.75.POSTED!not-for-mail
From: bl...@ckb.ird (corvid)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 13:53:59 -0700
Organization: The 27 Club
Message-ID: <t5udl7$1bh6$1@gioia.aioe.org>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<t5tqnl$eg5$1@gioia.aioe.org>
<930a2a0a-712f-98dd-0576-108b21f8e79e@electrooptical.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Info: gioia.aioe.org; logging-data="44582"; posting-host="xUOiStaTX9GQDNXPji0+sg.user.gioia.aioe.org"; mail-complaints-to="abuse@aioe.org";
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
Gecko/20100101 Thunderbird/91.9.0
Content-Language: en-US
X-Notice: Filtered by postfilter v. 0.9.2
 by: corvid - Mon, 16 May 2022 20:53 UTC

On 5/16/22 13:26, Phil Hobbs wrote:

>>> Also, there's no simultaneity between separated objects moving at
>>> different speeds. The relativistic garage illustrates this.
>>>
>>> Say you have a 1927 Bugatti Type 41, which is 252 inches long.
>>> Your garage is the standard 20 feed (240 inches) long, and has a
>>> very fast automatically-controlled door at each end. The doors
>>> are designed to open and close automatically to allow the car to
>>> enter and leave.
>>>
>>> Because the Bugatti is so fast, you drive towards the open end
>>> of the garage at 0.5c. You measure the length of the garage as
>>>
>>> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>>>
>>> The hood of the car passes through the open door, then the closed
>>> door opens before the back bumper has passed through the
>>> doorway. No collision occurs, because the second door opens
>>> before the first one closes.
>>>
>>> Your spouse, waiting for you to come home from your drive,
>>> measures the length of the car as
>>>
>>> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>>>
>>> The car fits into the garage, so as it enters, the first door
>>> closes before the second door opens. Once again no collision
>>> occurs, because the car is shorter than the garage.
>>>
>>> The math works out fine in both English and metric, and no
>>> paradoxes are involved.
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>
>> But, but... the bottom of the tires are in contact with the garage
>> floor. Shouldn't that anchor the Bugatti and garage into the same
>> frame?
>
> And the pistons are going up and down pretty good too. ;)
>
> Just stick with the front and rear bumpers for present purposes.
>
> Cheers
>
> Phil Hobbs

Now I want to tweak the car and garage lengths, and the speed, so that
the car goes thru unscathed in one frame but gets smashed in the other.
Is it possible?

Re: The Twins Paradox in Relativity

<16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97009&group=sci.electronics.design#97009

 copy link   Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com> <t5qekr$hnd$1@dont-email.me> <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
From: no.s...@please.net (Clifford Heath)
Date: Tue, 17 May 2022 08:55:29 +1000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Lines: 11
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer02.iad!feed-me.highwinds-media.com!news.highwinds-media.com!feeder.usenetexpress.com!tr3.iad1.usenetexpress.com!news.thecubenet.com!not-for-mail
NNTP-Posting-Date: Mon, 16 May 2022 22:55:32 +0000
Organization: theCubeNet - www.thecubenet.com
X-Complaints-To: abuse@thecubenet.com
Message-ID: <16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com>
X-Received-Bytes: 1315
 by: Clifford Heath - Mon, 16 May 2022 22:55 UTC

On 17/5/22 12:18 am, Phil Hobbs wrote:
> then the closed door opens before the back bumper has passed through the
> doorway.  No collision occurs

Umm, sorry? "before"? Is that a slip? Did you mean "as the back bumper
passes through the doorway?

Very cool illustration BTW. I want to use it, but want to make sure I
have it correct first.

Clifford Heath.

Re: The Twins Paradox in Relativity

<57fee176-5faf-94a7-87bf-f01002a71ca0@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97012&group=sci.electronics.design#97012

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Mon, 16 May 2022 19:42:29 -0400
Organization: A noiseless patient Spider
Lines: 36
Message-ID: <57fee176-5faf-94a7-87bf-f01002a71ca0@electrooptical.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Info: reader02.eternal-september.org; posting-host="18edbdc398715c5fc74149c1d67fa8ac";
logging-data="943"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/rdmaCbC3Gt2oxuZCIUM/I"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:9BKmRtAxgCfffgvLtN8V/UJ7nGE=
In-Reply-To: <16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com>
 by: Phil Hobbs - Mon, 16 May 2022 23:42 UTC

Clifford Heath wrote:
> On 17/5/22 12:18 am, Phil Hobbs wrote:
>> then the closed door opens before the back bumper has passed through
>> the doorway.  No collision occurs
>
> Umm, sorry? "before"? Is that a slip? Did you mean "as the back bumper
> passes through the doorway?

No, the point is that seen from a point in the car's reference frame,
the events happen *in a different order* from what you'd see in the
garage's frame.

> Very cool illustration BTW. I want to use it, but want to make sure I
> have it correct first.
>
> Clifford Heath.

I picked the Bugatti because I'm a fan, and looked up the standard
length of a garage on the net--the fact that it worked out well with a
speed of c/2 was fortuitous. (I'm very far from the first to use that
general sort of illustration, of course, but it's a fun one.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<e960815b-778c-41d6-f0c4-15d45031c609@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97015&group=sci.electronics.design#97015

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail
NNTP-Posting-Date: Mon, 16 May 2022 21:30:02 -0500
Subject: Re: The Twins Paradox in Relativity
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<t5tqnl$eg5$1@gioia.aioe.org>
<930a2a0a-712f-98dd-0576-108b21f8e79e@electrooptical.net>
<t5udl7$1bh6$1@gioia.aioe.org>
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Message-ID: <e960815b-778c-41d6-f0c4-15d45031c609@electrooptical.net>
Date: Mon, 16 May 2022 22:30:01 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
MIME-Version: 1.0
In-Reply-To: <t5udl7$1bh6$1@gioia.aioe.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Lines: 68
X-Trace: sv3-qulk9XRtD4YI/UbumeyqFPeoRukCtTbSU0NusV2SmEgAf2wDLb55kt4MhtTAw10D2wqwUqk/1BxBLca!I1GE30LVuzfCIQFgxIG3eqILplXukBluX/zAPhAl+Aiy3Q7m0/ipTa6TVN/BSLpqhgiSK1gtC8TB!ZtNKY2b0HcZuNX884rCEQ10=
X-Complaints-To: www.supernews.com/docs/abuse.html
X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 3844
 by: Phil Hobbs - Tue, 17 May 2022 02:30 UTC

corvid wrote:
> On 5/16/22 13:26, Phil Hobbs wrote:
>
>>>> Also, there's no simultaneity between separated objects moving at
>>>>  different speeds.  The relativistic garage illustrates this.
>>>>
>>>> Say you have a 1927 Bugatti Type 41, which is 252 inches long. Your
>>>> garage is the standard 20 feed (240 inches) long, and has a very
>>>> fast automatically-controlled door at each end.  The doors are
>>>> designed to open and close automatically to allow the car to enter
>>>> and leave.
>>>>
>>>> Because the Bugatti is so fast, you drive towards the open end
>>>> of the garage at 0.5c.  You measure the length of the garage as
>>>>
>>>> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>>>>
>>>> The hood of the car passes through the open door, then the closed
>>>>  door opens before the back bumper has passed through the
>>>> doorway. No collision occurs, because the second door opens
>>>> before the first one closes.
>>>>
>>>> Your spouse, waiting for you to come home from your drive, measures
>>>> the length of the car as
>>>>
>>>> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>>>>
>>>> The car fits into the garage, so as it enters, the first door closes
>>>> before the second door opens.  Once again no collision occurs,
>>>> because the car is shorter than the garage.
>>>>
>>>> The math works out fine in both English and metric, and no paradoxes
>>>> are involved.
>>>>

>>>
>>> But, but...  the bottom of the tires are in contact with the garage
>>>  floor. Shouldn't that anchor the Bugatti and garage into the same
>>> frame?
>>
>> And the pistons are going up and down pretty good too. ;)
>>
>> Just stick with the front and rear bumpers for present purposes.
>>
>
> Now I want to tweak the car and garage lengths, and the speed, so that
> the car goes thru unscathed in one frame but gets smashed in the other.
> Is it possible?

Nope. When a collision occurs, it's because the two objects moving at
different speeds are trying to be in the same place at once. If there's
no difference in position, you can have simultaneity, same as if there's
no difference in speed.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<16efd6d285a329a8$1$984316$6edd646a@news.thecubenet.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97025&group=sci.electronics.design#97025

 copy link   Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com> <t5qekr$hnd$1@dont-email.me> <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net> <16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com> <57fee176-5faf-94a7-87bf-f01002a71ca0@electrooptical.net>
From: no.s...@please.net (Clifford Heath)
Date: Tue, 17 May 2022 18:23:05 +1000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <57fee176-5faf-94a7-87bf-f01002a71ca0@electrooptical.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Lines: 31
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!feeder.usenetexpress.com!tr1.iad1.usenetexpress.com!news.thecubenet.com!not-for-mail
NNTP-Posting-Date: Tue, 17 May 2022 08:23:07 +0000
X-Complaints-To: abuse@thecubenet.com
Organization: theCubeNet - www.thecubenet.com
Message-ID: <16efd6d285a329a8$1$984316$6edd646a@news.thecubenet.com>
X-Received-Bytes: 2273
 by: Clifford Heath - Tue, 17 May 2022 08:23 UTC

On 17/5/22 9:42 am, Phil Hobbs wrote:
> Clifford Heath wrote:
>> On 17/5/22 12:18 am, Phil Hobbs wrote:
>>> then the closed door opens before the back bumper has passed through
>>> the doorway.  No collision occurs
>>
>> Umm, sorry? "before"? Is that a slip? Did you mean "as the back bumper
>> passes through the doorway?
>
> No, the point is that seen from a point in the car's reference frame,
> the events happen *in a different order* from what you'd see in the
> garage's frame.

Oh ok, I get it.

>> Very cool illustration BTW. I want to use it, but want to make sure I
>> have it correct first.
>>
>> Clifford Heath.
>
> I picked the Bugatti because I'm a fan,

My grandfather had a Type 40 for a while - it's now restored and living
in a garage 15km from here. But his really interesting car that I'd like
to find more about was a Lea-Francis "Hyper" - the first supercharged
British production car. He used to race that at the Albert Park track
and the Philip Island track, which are both current or previous F1
tracks. I don't think he ever entered F1, but I have a number of photos
he took while flag marshalling at Phillip Island in 1933.

Clifford Heath.

Re: The Twins Paradox in Relativity

<t5voau$pj1$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97026&group=sci.electronics.design#97026

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: cli...@nowaytoday.co.uk (Clive Arthur)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Tue, 17 May 2022 10:02:20 +0100
Organization: A noiseless patient Spider
Lines: 25
Message-ID: <t5voau$pj1$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
<t5tk43$ldi$1@dont-email.me>
Reply-To: clive@nowaytoday.co.uk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Tue, 17 May 2022 09:02:22 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="2c565400d9654f17edecf36b356a35ef";
logging-data="26209"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/vyjq6iOSJYzQopcP6NyQH9HPQcAB+RQ4="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:dDVla01jbQFKNAiTEwALcA90sHs=
In-Reply-To: <t5tk43$ldi$1@dont-email.me>
Content-Language: en-GB
 by: Clive Arthur - Tue, 17 May 2022 09:02 UTC

On 16/05/2022 14:38, Dimiter_Popoff wrote:

<snipped>

> I have been digging into physics just as much as it takes to do what I
> do so me being naive with that sort of thing is no surprise. I am
> vaguely aware of what your references say, I think I may have read some
> of these some time ago.
> What I don't get though is the flashing light on the train thing.
> Looks obvious to me that the observed period depends on the movement
> direction (assuming gravity is constant, i.e. it is no factor).
> In fact this should be easily measurable (not that I would go into
> it, just wondering if you or someone else has an explanation, I am
> not the "out there to challenge the science" type, more the "curious
> until things get clarified for me" sort).

One extra thing - the (very fast) train's time is dilated, so if both
stationary you (ie, waiting in the station) and the driver are both
flashing at 1Hz, he'll send fewer flashes than you.

Is that right?

--
Cheers
Clive

Re: The Twins Paradox in Relativity

<06f8aa06-31ae-7674-5e05-ebebd521c474@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97045&group=sci.electronics.design#97045

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Tue, 17 May 2022 10:55:41 -0400
Organization: A noiseless patient Spider
Lines: 49
Message-ID: <06f8aa06-31ae-7674-5e05-ebebd521c474@electrooptical.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<16efb7d948a4c757$1$1174340$e2dde862@news.thecubenet.com>
<57fee176-5faf-94a7-87bf-f01002a71ca0@electrooptical.net>
<16efd6d285a329a8$1$984316$6edd646a@news.thecubenet.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Info: reader02.eternal-september.org; posting-host="f719905f5d8ef1319fbcb5fbfed4b5fc";
logging-data="30666"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+sSY+o2bdPIFcTDUPV8InR"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:Z+fZl3S4oGxynYYu+rVDPZsiT7s=
In-Reply-To: <16efd6d285a329a8$1$984316$6edd646a@news.thecubenet.com>
 by: Phil Hobbs - Tue, 17 May 2022 14:55 UTC

Clifford Heath wrote:
> On 17/5/22 9:42 am, Phil Hobbs wrote:
>> Clifford Heath wrote:
>>> On 17/5/22 12:18 am, Phil Hobbs wrote:
>>>> then the closed door opens before the back bumper has passed through
>>>> the doorway.  No collision occurs
>>>
>>> Umm, sorry? "before"? Is that a slip? Did you mean "as the back
>>> bumper passes through the doorway?
>>
>> No, the point is that seen from a point in the car's reference frame,
>> the events happen *in a different order* from what you'd see in the
>> garage's frame.
>
> Oh ok, I get it.
>
>>> Very cool illustration BTW. I want to use it, but want to make sure I
>>> have it correct first.
>>>
>>> Clifford Heath.
>>
>> I picked the Bugatti because I'm a fan,
>
> My grandfather had a Type 40 for a while - it's now restored and living
> in a garage 15km from here. But his really interesting car that I'd like
> to find more about was a Lea-Francis "Hyper" - the first supercharged
> British production car. He used to race that at the Albert Park track
> and the Philip Island track, which are both current or previous F1
> tracks. I don't think he ever entered F1, but I have a number of photos
> he took while flag marshalling at Phillip Island in 1933.
>
> Clifford Heath.

Fun!

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<Qb6dnZ_MJZ4-txj_nZ2dnZeNn_fNnZ2d@giganews.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97101&group=sci.electronics.design#97101

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!buffer1.nntp.dca1.giganews.com!news.giganews.com.POSTED!not-for-mail
NNTP-Posting-Date: Wed, 18 May 2022 17:19:31 +0000
Reply-To: "Kevin Aylward" <kevinRemoveandReplaceATkevinaylward.co.uk>
From: kevinRem...@nowhere (Kevin Aylward)
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
In-Reply-To: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
Subject: Re: The Twins Paradox in Relativity
Date: Wed, 18 May 2022 18:23:22 +0100
MIME-Version: 1.0
Content-Type: text/plain;
format=flowed;
charset="iso-8859-1";
reply-type=original
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
Importance: Normal
X-Newsreader: Microsoft Windows Live Mail 16.4.3528.331
X-MimeOLE: Produced By Microsoft MimeOLE V16.4.3528.331
Message-ID: <Qb6dnZ_MJZ4-txj_nZ2dnZeNn_fNnZ2d@giganews.com>
Lines: 26
X-Usenet-Provider: http://www.giganews.com
X-Trace: sv3-2dgE2cwPy4MP8fEKKnfP26v5xd1hSswPGw30vxC7CFWYal7XPXAdkoEWPJRVX0TN6nogj6SboagP12D!fKEGdAB3XVZBEFR/sPhBKG4pgHBxsJvZckO/rTmbgyV12W0WWT/eWbCuGEC3Fkr4aE34/uxoEmha!Tg==
X-Complaints-To: abuse@giganews.com
X-DMCA-Notifications: http://www.giganews.com/info/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 1961
 by: Kevin Aylward - Wed, 18 May 2022 17:23 UTC

>It turns out there is a long history, with many parallel explanations:

Yep... pretty much all wrong....

..<https://en.wikipedia.org/wiki/Twin_paradox>

>Joe Gwinn

Well...... An actually correct account of the solution to the "Twins
Paradox" is here:

It explains the situation without accelerations, or frame switching. Yep.
Trust me, this is the real deal...:-)

https://www.kevinaylward.co.uk/gr/twinsparadox/twinsparadox.htm

-- Kevin Aylward

http://www.anasoft.co.uk/ SuperSpice
http://www.kevinaylward.co.uk/ee/index.html

Re: The Twins Paradox in Relativity

<4MmdnT65Aqumthj_nZ2dnZeNn_fNnZ2d@giganews.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97102&group=sci.electronics.design#97102

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!news.giganews.com.POSTED!not-for-mail
NNTP-Posting-Date: Wed, 18 May 2022 17:22:03 +0000
Reply-To: "Kevin Aylward" <kevinRemoveandReplaceATkevinaylward.co.uk>
From: kevinRem...@nowhere (Kevin Aylward)
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com> <t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
In-Reply-To: <t5tia2$6m9$1@gioia.aioe.org>
Subject: Re: The Twins Paradox in Relativity
Date: Wed, 18 May 2022 18:25:55 +0100
MIME-Version: 1.0
Content-Type: text/plain;
format=flowed;
charset="utf-8";
reply-type=response
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
Importance: Normal
X-Newsreader: Microsoft Windows Live Mail 16.4.3528.331
X-MimeOLE: Produced By Microsoft MimeOLE V16.4.3528.331
Message-ID: <4MmdnT65Aqumthj_nZ2dnZeNn_fNnZ2d@giganews.com>
Lines: 92
X-Usenet-Provider: http://www.giganews.com
X-Trace: sv3-ecpWG65T4OGXNDgBpBRyl8Ba9Ln+oN4JNocQpAQZVXPlY3yVzkF4X+m2g/xdcp97p1g042eF4HxqWm8!nG07jqS5C9yYVB5HJCrdcUDanrxmOfdjRgfSMSRzSiS6av87PAMJKw/KqmPVYQsy9YcE5xHVBLBe!4Q==
X-Complaints-To: abuse@giganews.com
X-DMCA-Notifications: http://www.giganews.com/info/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 5052
 by: Kevin Aylward - Wed, 18 May 2022 17:25 UTC

"Martin Brown" wrote in message news:t5tia2$6m9$1@gioia.aioe.org...

On 15/05/2022 12:05, Dimiter_Popoff wrote:
> On 5/15/2022 0:35, Joe Gwinn wrote:
>> It turns out there is a long history, with many parallel explanations:
>>
>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>
>> Joe Gwinn
>
> And it explains why clocks at the equator and on the poles run
> the same without involving gravity.

>Actually they don't.

>>One of Einstein's minor errors in his 1905 paper on special relativity was
>>to predict how much slower a clock at the equator would tick when compared
>>to one at the pole (due to the extra rotational speed of a clock at the
>>equator). Every now and then someone points it out... eg

>>https://physicstoday.scitation.org/doi/10.1063/1.1897562#

>>They only run at the same speed when *both* the GR and SR corrections are
>>applied simultaneously and only then at mean sea level.

>>It is hard to get your head round but everybody's clock ticks at a
>>different speed. Your head ages marginally more quickly than your feet.

Often quoted, but wrong. Its not how SR works.

In Special Relativity, clocks do not tick at different rates

Its a fundamental axiom of special relativity that "the laws of physics are
indepandant of inertial motion". This means, according to special
relativity, clocks must always tick at the same rate.

SR explains the apparent measurement of clock ticks reading slow by "time
travel". One travels through time at different t rates. Its a subtitle, but
important distinction.

Special Relativity holds that for example, one can cover time at a rate of
say, 100 secs/sec

Consider Dr.Who in his Tardis. He is traveling into the future , his own
ageing and clok ticks stay the same , for him, but he gets to the future
before someone else. If Dr. Who sent pulses as he is traveling, as he is
observe red to be traveling into the future, the received clock pulses would
be received as if slower .

The analogy is that there are many routes from London to Edinburgh. The
odometer will read different distances, but it always clocks up distance at
the same rate.

Clocks actually slowing down is a feature of the Lorentz Ether Theory, known
prior to the invention of SR and which Special Relativity claims to be
superior to.

The elephant in the room is that if the SR model is correct, then it leads
to the "Block Universe", that is, intrinsic to SR is that the future already
exists for everyone. This is in direct contradiction to Quantum Mechanics,
which holds that the future is intrinsically non deterministic.

Of note, is that QFT, is, essentially, and Ether theory in denial:

Professor (UK head of department) of Physics at Cambridge, David Tong (Adams
prize winner) has a YouTube general audience lecture on QFT:

https://www.youtube.com/watch?v=zNVQfWC_evg

0:31 - "...What are we made of...what are the fundamental building
blocks of nature...?"

19:30 - "... so there is spread something throughout this room, something
we call the electron field..its like a fluid that fills ..the entire
universe..and the ripples of this electron fluid..the waves of this fluid
get tied into little bundles of energy, by the rules of quantum
mechanics..and these bundles of energy are what we call the particle the
electron....and the same is true for every kind of particle in the
universe..."

Kevin Aylward

https://www.kevinaylward.co.uk/gr/index.html
http://www.anasoft.co.uk/ SuperSpice
http://www.kevinaylward.co.uk/ee/index.html

Re: The Twins Paradox in Relativity

<OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97107&group=sci.electronics.design#97107

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder8.news.weretis.net!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!buffer1.nntp.dca1.giganews.com!news.giganews.com.POSTED!not-for-mail
NNTP-Posting-Date: Wed, 18 May 2022 15:24:55 -0500
Date: Wed, 18 May 2022 13:24:54 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:91.0)
Gecko/20100101 Thunderbird/91.8.1
Reply-To: spam@flippers.com
Subject: Re: The Twins Paradox in Relativity
Content-Language: en-US
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
From: spa...@flippers.com (John Robertson)
In-Reply-To: <a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: base64
Message-ID: <OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>
Lines: 67
X-Usenet-Provider: http://www.giganews.com
X-Trace: sv3-KeogeRZ0i8VcPUrspzWFmfSMa4WMbd84mhujWSym2ihTuzFXVehPxCTH84JOaGHxSTsToRJwDC80vy4!jk5CO612cmI11UNEb35zELPagF6+7egXbqWbdTIlOdojrbC/BP+7ejk5eH37Khr5WztLdAFnOuc=
X-Complaints-To: abuse@giganews.com
X-DMCA-Notifications: http://www.giganews.com/info/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 6265
 by: John Robertson - Wed, 18 May 2022 20:24 UTC


On 2022/05/16 7:18 a.m., Phil Hobbs wrote:
> Jeff Layman wrote:
>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>> It turns out there is a long history, with many parallel explanations:
>>>
>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>
>> It can be expanded to the Triplets Paradox, for example
>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>
>> SRT is well above me, I'm afraid. Some of the explanation of the Twins
>> Paradox refers to the twins' clocks transmitting their time to the
>> other twin (the clock signal is transmitted at the speed of light).
>> Even allowing for the travelling twin's speed when approaching the
>> speed of light, and the relativistic effect it has on each clock's
>> perceived time, as the travelling twin's speed doesn't exceed that
>> speed, each twin will, eventually, receive the clock time of the other.
>>
>> But what happens with the Triplet Paradox where the moving triplets
>> are accelerating away from each other? Once they've "exceeded" C in
>> relation to each other, although they can receive the stationary
>> triplet's clock reading (and he can receive theirs), can one moving
>> triplet still receive the other moving triplet's clock signal? If
>> there is such a moment when they can no longer receive each other's
>> signal, when they finally stop moving away and start moving towards
>> each other again, will there be a moment when they suddenly start
>> receiving that "missing" clock signal as they catch up with it (or
>> perhaps it catches up with them)? Will there be a specific moment when
>> they not only receive a missing clock time, but coincidentally receive
>> the "accurate" time as transmitted by the other moving triplet, so
>> appear to be receiving two different clock readings at the same time?
>>
>
> If you shine your laser pointer at two points 180 degrees apart in the
> sky, the relative speed of the light pulses in your frame of reference
> is 2c.  No paradox is involved.
>
> Also, there's no simultaneity between separated objects moving at
> different speeds.  The relativistic garage illustrates this.
>
> Say you have a 1927 Bugatti Type 41, which is 252 inches long.  Your
> garage is the standard 20 feed (240 inches) long, and has a very fast
> automatically-controlled door at each end.  The doors are designed to
> open and close automatically to allow the car to enter and leave.
>
> Because the Bugatti is so fast, you drive towards the open end of the
> garage at 0.5c.  You measure the length of the garage as
>
> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>
> The hood of the car passes through the open door, then the closed door
> opens before the back bumper has passed through the doorway.  No
> collision occurs, because the second door opens before the first one
> closes.
>
> Your spouse, waiting for you to come home from your drive, measures the
> length of the car as
>
> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>
> The car fits into the garage, so as it enters, the first door closes
> before the second door opens.  Once again no collision occurs, because
> the car is shorter than the garage.
>
> The math works out fine in both English and metric, and no paradoxes are
> involved.
>
> Cheers
>
> Phil Hobbs
>
How fast do the doors have to rise or close to clear the car...this
seems to be getting annoying close to the speed of light.
Pretty sure my garage door would warp if I ran it that fast! (ducking)
John ;-#)#

Re: The Twins Paradox in Relativity

<t63qlh$2k0$1@dont-email.me>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97119&group=sci.electronics.design#97119

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: cli...@nowaytoday.co.uk (Clive Arthur)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Wed, 18 May 2022 23:06:38 +0100
Organization: A noiseless patient Spider
Lines: 13
Message-ID: <t63qlh$2k0$1@dont-email.me>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qmq2$78i$1@dont-email.me> <t5tia2$6m9$1@gioia.aioe.org>
<4MmdnT65Aqumthj_nZ2dnZeNn_fNnZ2d@giganews.com>
Reply-To: clive@nowaytoday.co.uk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Wed, 18 May 2022 22:06:41 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="f408969eca6ca0381ade7cf9b95a2e77";
logging-data="2688"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+jmXUSCoqkytC2YNH0lr6tYyhyc27Bk6E="
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
Thunderbird/91.9.0
Cancel-Lock: sha1:Oi9nSPI590vpXpRi8Cn9BQw3KZY=
In-Reply-To: <4MmdnT65Aqumthj_nZ2dnZeNn_fNnZ2d@giganews.com>
Content-Language: en-GB
 by: Clive Arthur - Wed, 18 May 2022 22:06 UTC

Hi Kevin

What is the speed of a photon from the photon's POV? I think it must be
infinite, am I right?

Likewise, a sufficiently fast spaceship would have a speedometer showing
its speed as being >c? Is that right?

--
Cheers
Clive

Re: The Twins Paradox in Relativity

<cf096739-0fda-0779-5c07-7ea40c24f541@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97127&group=sci.electronics.design#97127

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Newsgroups: sci.electronics.design
Subject: Re: The Twins Paradox in Relativity
Date: Wed, 18 May 2022 21:53:20 -0400
Organization: A noiseless patient Spider
Lines: 99
Message-ID: <cf096739-0fda-0779-5c07-7ea40c24f541@electrooptical.net>
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Injection-Info: reader02.eternal-september.org; posting-host="0a289c889749f8cbc36cbcc83c5c93f4";
logging-data="27251"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+x0T4LlVTiGKePpeI2Wykq"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
Cancel-Lock: sha1:dViR4oOxoYSvCC/c76lUri8lB2c=
In-Reply-To: <OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>
 by: Phil Hobbs - Thu, 19 May 2022 01:53 UTC

John Robertson wrote:
>
> On 2022/05/16 7:18 a.m., Phil Hobbs wrote:
>> Jeff Layman wrote:
>>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>>> It turns out there is a long history, with many parallel explanations:
>>>>
>>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>>
>>> It can be expanded to the Triplets Paradox, for example
>>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>>
>>> SRT is well above me, I'm afraid. Some of the explanation of the
>>> Twins Paradox refers to the twins' clocks transmitting their time to
>>> the other twin (the clock signal is transmitted at the speed of
>>> light). Even allowing for the travelling twin's speed when
>>> approaching the speed of light, and the relativistic effect it has on
>>> each clock's perceived time, as the travelling twin's speed doesn't
>>> exceed that speed, each twin will, eventually, receive the clock time
>>> of the other.
>>>
>>> But what happens with the Triplet Paradox where the moving triplets
>>> are accelerating away from each other? Once they've "exceeded" C in
>>> relation to each other, although they can receive the stationary
>>> triplet's clock reading (and he can receive theirs), can one moving
>>> triplet still receive the other moving triplet's clock signal? If
>>> there is such a moment when they can no longer receive each other's
>>> signal, when they finally stop moving away and start moving towards
>>> each other again, will there be a moment when they suddenly start
>>> receiving that "missing" clock signal as they catch up with it (or
>>> perhaps it catches up with them)? Will there be a specific moment
>>> when they not only receive a missing clock time, but coincidentally
>>> receive the "accurate" time as transmitted by the other moving
>>> triplet, so appear to be receiving two different clock readings at
>>> the same time?
>>>
>>
>> If you shine your laser pointer at two points 180 degrees apart in the
>> sky, the relative speed of the light pulses in your frame of reference
>> is 2c.  No paradox is involved.
>>
>> Also, there's no simultaneity between separated objects moving at
>> different speeds.  The relativistic garage illustrates this.
>>
>> Say you have a 1927 Bugatti Type 41, which is 252 inches long.  Your
>> garage is the standard 20 feed (240 inches) long, and has a very fast
>> automatically-controlled door at each end.  The doors are designed to
>> open and close automatically to allow the car to enter and leave.
>>
>> Because the Bugatti is so fast, you drive towards the open end of the
>> garage at 0.5c.  You measure the length of the garage as
>>
>> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>>
>> The hood of the car passes through the open door, then the closed door
>> opens before the back bumper has passed through the doorway.  No
>> collision occurs, because the second door opens before the first one
>> closes.
>>
>> Your spouse, waiting for you to come home from your drive, measures
>> the length of the car as
>>
>> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>>
>> The car fits into the garage, so as it enters, the first door closes
>> before the second door opens.  Once again no collision occurs, because
>> the car is shorter than the garage.
>>
>> The math works out fine in both English and metric, and no paradoxes
>> are involved.

>
> How fast do the doors have to rise or close to clear the car...this
> seems to be getting annoying close to the speed of light.
>
> Pretty sure my garage door would warp if I ran it that fast! (ducking)

As I mentioned upthread, the pistons would be going up and down at
impressive speeds too. ;)

The garage thing can be crispened up so as to be practically measurable.
The point of the doors is that if a collision occurs, it occurs in all
reference frames.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultbant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Re: The Twins Paradox in Relativity

<5dace25c-240d-90a0-a547-a389b5f7dad5@electrooptical.net>

 copy mid

https://www.novabbs.com/tech/article-flat.php?id=97138&group=sci.electronics.design#97138

 copy link   Newsgroups: sci.electronics.design
Path: i2pn2.org!i2pn.org!weretis.net!feeder6.news.weretis.net!news.misty.com!border2.nntp.dca1.giganews.com!nntp.giganews.com!buffer2.nntp.dca1.giganews.com!buffer1.nntp.dca1.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail
NNTP-Posting-Date: Thu, 19 May 2022 01:54:44 -0500
Subject: Re: The Twins Paradox in Relativity
Newsgroups: sci.electronics.design
References: <m0808htf06rtm8lojc0v93ngl473uci176@4ax.com>
<t5qekr$hnd$1@dont-email.me>
<a526ce6c-e9fc-a5a9-53ed-91fd045e6268@electrooptical.net>
<OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>
From: pcdhSpam...@electrooptical.net (Phil Hobbs)
Message-ID: <5dace25c-240d-90a0-a547-a389b5f7dad5@electrooptical.net>
Date: Thu, 19 May 2022 02:54:43 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
Thunderbird/78.0
MIME-Version: 1.0
In-Reply-To: <OLudnZ7b78SKyxj_nZ2dnUU7-TOdnZ2d@giganews.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Lines: 108
X-Trace: sv3-1zWQduIYgZy2SnGsD7feABKnttX/MJPN/H1ruDlxS59LSoQv4LjJqnpX/57k+gGH5zCUBowbqmr+b/G!XbeKJqirJU056mIKysSacdoswwX4kQog2bHZoibSrpqSxaYsXEKIymq5MmGWPjzKp9jEz1zwyIeA!RKZSeOwF/uOz7Yb6fOYHag==
X-Complaints-To: www.supernews.com/docs/abuse.html
X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.40
X-Original-Bytes: 5657
 by: Phil Hobbs - Thu, 19 May 2022 06:54 UTC

John Robertson wrote:
>
> On 2022/05/16 7:18 a.m., Phil Hobbs wrote:
>> Jeff Layman wrote:
>>> On 14/05/2022 22:35, Joe Gwinn wrote:
>>>> It turns out there is a long history, with many parallel explanations:
>>>>
>>>> .<https://en.wikipedia.org/wiki/Twin_paradox>
>>>
>>> It can be expanded to the Triplets Paradox, for example
>>> <http://www.mysearch.org.uk/website1/html/251.Triplets.html>
>>>
>>> SRT is well above me, I'm afraid. Some of the explanation of the
>>> Twins Paradox refers to the twins' clocks transmitting their time to
>>> the other twin (the clock signal is transmitted at the speed of
>>> light). Even allowing for the travelling twin's speed when
>>> approaching the speed of light, and the relativistic effect it has on
>>> each clock's perceived time, as the travelling twin's speed doesn't
>>> exceed that speed, each twin will, eventually, receive the clock time
>>> of the other.
>>>
>>> But what happens with the Triplet Paradox where the moving triplets
>>> are accelerating away from each other? Once they've "exceeded" C in
>>> relation to each other, although they can receive the stationary
>>> triplet's clock reading (and he can receive theirs), can one moving
>>> triplet still receive the other moving triplet's clock signal? If
>>> there is such a moment when they can no longer receive each other's
>>> signal, when they finally stop moving away and start moving towards
>>> each other again, will there be a moment when they suddenly start
>>> receiving that "missing" clock signal as they catch up with it (or
>>> perhaps it catches up with them)? Will there be a specific moment
>>> when they not only receive a missing clock time, but coincidentally
>>> receive the "accurate" time as transmitted by the other moving
>>> triplet, so appear to be receiving two different clock readings at
>>> the same time?
>>>
>>
>> If you shine your laser pointer at two points 180 degrees apart in the
>> sky, the relative speed of the light pulses in your frame of reference
>> is 2c.  No paradox is involved.
>>
>> Also, there's no simultaneity between separated objects moving at
>> different speeds.  The relativistic garage illustrates this.
>>
>> Say you have a 1927 Bugatti Type 41, which is 252 inches long.  Your
>> garage is the standard 20 feed (240 inches) long, and has a very fast
>> automatically-controlled door at each end.  The doors are designed to
>> open and close automatically to allow the car to enter and leave.
>>
>> Because the Bugatti is so fast, you drive towards the open end of the
>> garage at 0.5c.  You measure the length of the garage as
>>
>> 240 inches * sqrt(1-0.5**2) = 207.8 inches.
>>
>> The hood of the car passes through the open door, then the closed door
>> opens before the back bumper has passed through the doorway.  No
>> collision occurs, because the second door opens before the first one
>> closes.
>>
>> Your spouse, waiting for you to come home from your drive, measures
>> the length of the car as
>>
>> 252 inches * sqrt(1-0.5**2) = 218.2 inches.
>>
>> The car fits into the garage, so as it enters, the first door closes
>> before the second door opens.  Once again no collision occurs, because
>> the car is shorter than the garage.
>>
>> The math works out fine in both English and metric, and no paradoxes
>> are involved.
>>
>> Cheers
>>
>> Phil Hobbs
>>
>
> How fast do the doors have to rise or close to clear the car...this
> seems to be getting annoying close to the speed of light.
>
> Pretty sure my garage door would warp if I ran it that fast! (ducking)

There are also a few other practical problems, e.g. that the kinetic
energy of a 2000 kg car going at c/2 is

m c**2 (gamma -1) =
2000 kg * (299792458 m/s)**2 * ( 1 / sqrt(1-0.25) - 1 ) =
2.87E19 J.

That's 6653 megatons, at the usually quoted rate of 1 MT = 1e15 cal
(4.18E15 J).

The XKCD baseball is a mere 8 MT.
<https://what-if.xkcd.com/1/>.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Pages:12
server_pubkey.txt

rocksolid light 0.9.7
clearnet tor