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

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From: mpc755 on 1 Mar 2010 08:31

On Mar 1, 8:26 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
wrote:
> "mpalenik" <markpale...(a)gmail.com> wrote in message
>
> news:e4049f2a-c6d7-44da-a13c-432aeaf2344d(a)j27g2000yqn.googlegroups.com...
> On Mar 1, 2:15 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au>
> wrote:
>
> > "Ste" <ste_ro...(a)hotmail.com> wrote in message
> > > Dark matter is resistent to
> > > falsification, because it "does not interact except through gravity
> > > and inertia".
>
> > That does not stop dark matter being falsified, but does mean that
> > falsification would require us to change our theories on gravity and
> > inertia.
>
> Just wanted to point out, things don't interact through "inertia".
> Dark matter, under the WIMP theory, interacts only under gravity and
> the weak force.
>
> ___________________________
> Dark matter can do what it damn well likes, as long as nobody sees it.

Nobody sees it because it is aether. Matter and aether are different
states of the same material. Matter is compressed mather and aether is
uncompressed mather.

From: Peter Webb on 1 Mar 2010 08:31

"Ste" <ste_rose0(a)hotmail.com> wrote in message
news:ae1e0767-bbd7-4260-9be9-c5ad9a92d17f(a)v20g2000yqv.googlegroups.com...
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".

_____________________________
Which apparently it can't, or not in this Universe, anyway.

But if you insist on relying only on real-world tests,

_________________________
I don't, but experimental evidence is always great ...

then you can
always put a third observer equidistant from the two observers, and
this person would receive a signal from both observers simultaneously.

__________________________________
Yes you could.

Indeed, you could set up bazillions of experiments. Got any that disprove
SR? No? I thought not.

Next!

From: Peter Webb on 1 Mar 2010 08:43

>>
>> 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!

OK, you tell us.

It wouldn't cost you a "grand in money" as you said above. How long it takes
you is a question of how far you want to get, and where you are now. To
understand Minkowski spacetime you don't need calculus (though it obviously
helps), but you do need to know what "imaginary numbers" are, and what
vectors are. These are both taught in high school. If you understand both of
these concepts, picking up what Minkowski is about is very easy.

You can't expect to learn SR without making some effort.

From: Peter Webb on 1 Mar 2010 08:51

>> > Stop making me laugh Peter. I have surely forgotten more about
>> > evolution than you'll ever know, because you typify arrogance and
>> > closed-mindedness.
>>
>> I laughed when you first said what you thought evolution was about.
>>
>> You said it explained the origon of life (amongst other things).
>>
>> Evolution says nothing about that at all.
>
> Guffaw! "Evolution says nothing about the origin of life at all". I
> wonder if Dirk van de Moortel would like that one for his "immortal
> fumbles" page.
>

Interesting that you have forgotten more about evolution than I will ever
know, because I can't actually recall Darwin's theory of evolution as saying
anything at all about the origins of life.

What do you think it says about the origins of life, exactly?

(See. Like I said. You know even less about evolution than you do about SR.)

From: Jerry on 1 Mar 2010 09:15

On Feb 28, 11:20 am, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
> On Feb 27, 8:42 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote:

> > 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.
>
> > To Ste:
> > I actually prefer the first edition. It is a relatively thin,
> > large format paperback that is deceptively easy to skim through
> > without understanding. It is not a book for skimming. It has lots
> > of problems with solutions, and the only way to truly learn the
> > subject is to WORK THE PROBLEMS!!! None of the problems uses
> > advanced math. If you can work the problems and get the correct
> > answers, only then will you really understand what relativity is
> > all about.
>
> > As Peter pointed out, Minkowski spacetime is a superb conceptual
> > model, and not at all difficult to understand provided that you
> > take the time to learn it properly.
>
> > There is no shortcut to learning how to do the math.
> > But the math is simple!
>
> IMO that book stinks for explaining SR. It presents the math but
> doesn't provide the underlying reason for the math. To make matters
> worse it sometimes assumes the reader knows things without stating
> them. For example, in one of the first problems Billy (or whoever)
> *sees* a rocket fly by. He sees a spark as it passes a door frame at
> such and such a time. We then do some calculations. It was never
> mentioned that the times Billy uses are coordinate times read from
> clocks at the point where the event takes place, as opposed to the
> time on Billy's watch, including travel time.

BLATANT FALSEHOOD

In my first edition, Taylor and Wheeler devote over five pages to
the topic of measuring the coordinates of an event

Starting on page 17, I read the section heading and subtopics:
Chapter 1.4 The Coordinates of an Event
Why use coordinates?
Event defined
Latticework of clocks
Synchronizing clocks in lattice
Latticework used to measure the four coordinates of event
Lattice spacing depends on scale of physics under study
Observer defined
Clock records reveal motion of particle through lattice
Verifying that lattice furnishes inertial frame
Laboratory and rocket frames: axes coincide
Laboratory and rocket observers record single event
y coordinate of event is same in lab and rocket frames
z coordinate of event is same in lab and rocket frames

> Another thing I don't like is their constant repetition of how things
> aren't what we expect because we aren't used to dealing with the
> speeds involved.

BLATANT FALSEHOOD

I see exactly TWO instances, on page 5 and page 16, where Taylor
and Wheeler mention the discrepancy between relativity and
intuition.

This is NOT constant repetition, unless you can't count beyond 1.

> That's BS. Things aren't always what we expect
> because we aren't used to switching pespectives. When you are driving
> down the road the rain drops that fall straight down for the observer
> on the side of the road fall diagonally. There is nothing strange
> about that, it is just a different perspective. The goal here should
> be to make sense of what you see, not to show how weird they are. A
> good book for that is "Relativity And Common Sense" by Bondi.

NOT A TEXTBOOK,
DOES NOT FORCE READER TO CHECK THEIR UNDERSTANDING

Bondi followed Milne in eschewing the two postulates, instead
deriving special relativity by starting with the Doppler effect.
This is perfectly fine, but the book is not structured as a
textbook. It does not challenge the reader to check their
comprehension by forcing them to apply the concepts that they
have read, not necessarily with understanding.

Jerry