A constant speed of light in all reference frames? Surely you can't be serious. [Physics]

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From: Ste on 1 Mar 2010 04:59

On 1 Mar, 06:48, "Inertial" <relativ...(a)rest.com> wrote:
> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>
> > but in my scenario dealing with simply two specific
> > events, both are simultaneous in both frames.
>
> Yes .. it is possible to have some events simultaneous in multiple frames..
>
> But that does not make simultaneity universal in any sense, as other pairs
> of events that are simultaneous in on of those frames is not simultaneous in
> another.

Agreed. But what it does prove is that the lack of simultaneity is due
to propagation delays. The effect you're describing is exactly the
same for sound, and involves nothing physically profound.

> So regarding "what is simultaneous in one frame is not simultaneous in
> another" meaning "the set of all pairs of simultaneous events in one frame
> is NOT identical to the set of pairs of simultaneous events in another
> frame" is correct.
>
> THAT is the relevant point.

I'm not sure what the point is. My point is that the assertion that
"no two events that are simultaneous in one frame can be simultaneous
in another" is falsified. Yet that is precisely the assertion that has
been made on a number of occasions now, liberally salted with
allegations that I'm "an idiot", "need to learn physics", "don't know
anything", etc.

Now we see the boot is on the foot.

From: Inertial on 1 Mar 2010 05:02

"Ste" <ste_rose0(a)hotmail.com> wrote in message
news:c8ef826b-60b1-4480-86e8-0fe7bde83530(a)o3g2000yqb.googlegroups.com...
> On 1 Mar, 06:49, "Inertial" <relativ...(a)rest.com> wrote:
>> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>>
>> news:6d1b660b-6304-48b6-ab7f-5098e403bd5f(a)q23g2000yqd.googlegroups.com...
>>
>>
>>
>>
>>
>> > On 1 Mar, 05:19, "Inertial" <relativ...(a)rest.com> wrote:
>> >> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>>
>> >>news:320d036e-35c6-4a2b-ba4b-1d8e3a9067ba(a)z11g2000yqz.googlegroups.com...
>>
>> >> > On 28 Feb, 07:45, "Peter Webb"
>> >> > <webbfam...(a)DIESPAMDIEoptusnet.com.au>
>> >> > wrote:
>> >> >> I'm confused, because I thought we previously agreed that two
>> >> >> observers travelling along the same axis, maintaining equidistance
>> >> >> from both events at all times, would both report each event as
>> >> >> simultaneous with the other event. And moreover, if they not only
>> >> >> both
>> >> >> maintained equidistance from both events, but if they maintained a
>> >> >> separation which was equal for both observers (which, if both
>> >> >> observers are moving relative to each other, requires either a
>> >> >> collision course between observers, or travel in diametrically
>> >> >> opposite directions), then there is no question that the signals
>> >> >> are
>> >> >> received simultaneously.
>>
>> >> >> Illustration:
>>
>> >> >> E1
>>
>> >> >> --------
>>
>> >> >> E2
>>
>> >> >> The line represents the line between events E1 and E2, along which
>> >> >> the
>> >> >> observers may move while always reporting both events to be
>> >> >> simultaneous.
>>
>> >> >> _________________________________
>> >> >> You still don't get it. You can say two events appeared to
>> >> >> simultaneous
>> >> >> or
>> >> >> "were" simultaneous in *some* inertial reference frame. That does
>> >> >> *not*
>> >> >> mean
>> >> >> they appeared simultaneous or "were" simultaneous in some *other*
>> >> >> reference
>> >> >> frame. The concept that is lost is "absolute simultaneity", not
>> >> >> "simultaneity within a particular reference frame".
>>
>> >> > But clearly if the two *observers* are moving relative to each
>> >> > other,
>> >> > then this is the definitive proof that events can be simultaneous
>> >> > when
>> >> > measured from more than one reference frame.
>>
>> >> No .. it isn't. Do you know what an 'event' is?
>>
>> >> > And in some
>> >> > circumstances, the simultaneity also aquires an "absolute"
>> >> > character,
>>
>> >> Nope
>>
>> >> > in that the events would be observed to be simultaneous if the two
>> >> > observers were able to synchronise their clocks by a form of
>> >> > instantaneous communication.
>>
>> >> Clocks that are wrong can show any time you want. But differently
>> >> moving
>> >> observers will always read a different difference in time on a given
>> >> pair
>> >> of
>> >> separated clocks.
>>
>> > No they won't Inertial. I suggest you get out a paper and pencil, and
>> > do some working out.
>>
>> OK .. as long as they are separated in the direction of relative motion
>> between any given pair of observers.
>
> And I didn't even need a paper and pencil,

Neither did I

> and I don't even understand
> Minkowski spacetime.

I'm glad you're proud of your ignorance .. you have a lot to be proud of.

> I'll bet that really pisses you off!

Why would it. You're still wrong about simultaneity being absolute. For
any two events that are simultaneous in one inertial frame, there exist an
infinite number of inertial frames where they are not, and each has a
different difference in times for those events.

From: Inertial on 1 Mar 2010 05:07

"Ste" <ste_rose0(a)hotmail.com> wrote in message
news:ab068d2a-f703-4140-b625-33809addc9e0(a)g10g2000yqh.googlegroups.com...
> On 1 Mar, 06:48, "Inertial" <relativ...(a)rest.com> wrote:
>> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>>
>> > but in my scenario dealing with simply two specific
>> > events, both are simultaneous in both frames.
>>
>> Yes .. it is possible to have some events simultaneous in multiple
>> frames.
>>
>> But that does not make simultaneity universal in any sense, as other
>> pairs
>> of events that are simultaneous in on of those frames is not simultaneous
>> in
>> another.
>
> Agreed. But what it does prove is that the lack of simultaneity is due
> to propagation delays.

No .. it does not.

> The effect you're describing is exactly the
> same for sound, and involves nothing physically profound.

Nope. Totally different. You're simply ignorant.

>> So regarding "what is simultaneous in one frame is not simultaneous in
>> another" meaning "the set of all pairs of simultaneous events in one
>> frame
>> is NOT identical to the set of pairs of simultaneous events in another
>> frame" is correct.
>>
>> THAT is the relevant point.
>
> I'm not sure what the point is.

That you are wrong

> My point is that the assertion that
> "no two events that are simultaneous in one frame can be simultaneous
> in another" is falsified.

It was never claimed by SR .. so it is not any sort of victory for you.

> Yet that is precisely the assertion that has
> been made on a number of occasions now,

Probably taken out of context by you. Crackpots tend to do things like
that.

> liberally salted with
> allegations that I'm "an idiot", "need to learn physics", "don't know
> anything", etc.

You ARE an idiot. You DO need to learn physics. And you do NOT know much.

> Now we see the boot is on the foot.

Nope. You are STILL an idiot. You STILL need to learn physics. And you
STILL don't know much. You just demonstrated that above.

From: Ste on 1 Mar 2010 05:51

On 1 Mar, 07:24, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>
> But clearly if the two *observers* are moving relative to each other,
> then this is the definitive proof that events can be simultaneous when
> measured from more than one reference frame.
>
> ____________________________________
> Can appear simultaneous, yes, of course. That is a standard part of SR.

Not "can appear simultaneous".

*Is simultaneous*.

> And in some
> circumstances, the simultaneity also aquires an "absolute" character,
> in that the events would be observed to be simultaneous if the two
> observers were able to synchronise their clocks by a form of
> instantaneous communication.
>
> ________________________________
> "if the two observers were able to synchronise their clocks by a form of
> instantaneous communication.", or if pigs could fly, or Star Trek
> instantaneous teleporters existed, or I was the President of China.
>
> Show me how they can synchronise their clocks through instantaneous
> communication and you have an argument.

I'm not saying you can. I'm saying *if you could*. The definition of
"simultaneous", for any sane person, is always going to be "if
information could travel instantly".

But if you insist on relying only on real-world tests, then you can
always put a third observer equidistant from the two observers, and
this person would receive a signal from both observers simultaneously.

From: Ste on 1 Mar 2010 05:52

On 1 Mar, 07:49, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
> "Ste" <ste_ro...(a)hotmail.com> wrote in message
>
> On 28 Feb, 17:20, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
>
> > On Feb 27, 8:42 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote:
>
> > > You should give Ste a specific book recommendation:
>
> > > Spacetime Physics, by Taylor and Wheeler
>
> > > The second edition can generally be picked up used for about $25.
> > > The first edition is frequently found on eBay with a "Buy it now"
> > > price of $5 to $10.
>
> > [...]
>
> > IMO that book stinks for explaining SR. It presents the math but
> > doesn't provide the underlying reason for the math.
>
> Haha! And these pillocks wonder why I won't go out and spend a grand
> in money and 6 months of time, working through their extensive reading
> lists!
>
> ________________________________
> I don't wonder why don't learn SR. I think its because of two reasons.
> Firstly, you are lazy. Secondly, you have such a low opinion of your own
> abilities that you think you won't understand it anyway, so you think its a
> waste of time.

Guffaw!