What makes a formula - to be relativistic??
in [Relativity]
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From: Y.Porat on 3 Jul 2010 14:14 On Jul 3, 7:56 pm, Robert Higgins <robert_higgins...(a)hotmail.com> wrote: > On Jul 3, 2:23 am, "Y.Porat" <y.y.po...(a)gmail.com> wrote: > > > Wat makes a physics formula- to be relativistic??!! > > That it was developed by my RELATIVES! > > > > > TIA > > Y.Porat > > ------------------------------------- better say by parrots that dont know how and when to use it and when** not* to use it Y.P ---------------------
From: eric gisse on 3 Jul 2010 16:25 Inertial wrote: > "blackhead" wrote in message > news:3ff03b45-5b68-4aa8-93ce-abb573ac11e2(a)z10g2000yqb.googlegroups.com... >>It's relativistic if its form doesn't change when viewed from any >>frame using the transformations of relativity. > > I like that definition. Its' called 'Lorentz invariance', a concept Porat will never understand.
From: waldofj on 3 Jul 2010 18:22 On Jul 3, 8:58 am, "Inertial" <relativ...(a)rest.com> wrote: > "blackhead" wrote in message > > news:3ff03b45-5b68-4aa8-93ce-abb573ac11e2(a)z10g2000yqb.googlegroups.com... > > >It's relativistic if its form doesn't change when viewed from any > >frame using the transformations of relativity. > > I like that definition. I must disagree. That is the definition of a Lorentz invariant quantity, which is not necessarily relativistic. The links you provided earlier are much better definitions.
From: Inertial on 3 Jul 2010 18:43 "waldofj" wrote in message news:138bd120-927e-4c6f-9e7f-863b1a353057(a)c10g2000yqi.googlegroups.com... >On Jul 3, 8:58 am, "Inertial" <relativ...(a)rest.com> wrote: >> "blackhead" wrote in message >> news:3ff03b45-5b68-4aa8-93ce-abb573ac11e2(a)z10g2000yqb.googlegroups.com... >> >It's relativistic if its form doesn't change when viewed from any >> >frame using the transformations of relativity. >> >> I like that definition. > >I must disagree. That is the definition of a Lorentz invariant >quantity, Not a quantity in this case .. a formula > which is not necessarily relativistic. The links you >provided earlier are much better definitions. That said .. a 'relativistic' equation will satisfy Lorentz invariance, because SR has Lorentz transforms. And If a formula is NOT Lorentz invariant (ie it no longer applies at higher velocities), then it is not a 'relativistic' formula. So as per my original 'definition' of when I'd use 'relativistic' as an adjective for a formula .. it would be when there are two forms for a formula .. one that is as per Newtonian physics (and not Lorentz invariant ... only approximately correct when v <<c), and another form that IS Lorentz invariant (so works for larger v). Then I'd call the second form relativistic, and the former 'classical' or 'newtonian' etc. The relativistic formula would reduce to the classical form when v << c. If there's only one form, then no point adding the 'relativistic' adjective to it, unless one wants to emphasise the point that the formula comes from / is part of the theory of relativity. Of course, there really isn't anything of formal significance in using the word 'relativistic' as an adjective (though it does have some implications).
From: Androcles on 3 Jul 2010 19:04
"waldofj" <waldofj(a)verizon.net> wrote in message news:138bd120-927e-4c6f-9e7f-863b1a353057(a)c10g2000yqi.googlegroups.com... On Jul 3, 8:58 am, "Inertial" <relativ...(a)rest.com> wrote: > "blackhead" wrote in message > > news:3ff03b45-5b68-4aa8-93ce-abb573ac11e2(a)z10g2000yqb.googlegroups.com... > > >It's relativistic if its form doesn't change when viewed from any > >frame using the transformations of relativity. > > I like that definition. I must disagree. That is the definition of a Lorentz invariant quantity, which is not necessarily relativistic. The links you provided earlier are much better definitions. ========================================= Have a nice nitpick on the meaning of words. 'When I use a word,' Humpty Roberts said, in a rather scornful tone,' it means just what I choose it to mean, neither more nor less.' 'The question is,' said Alice, 'whether you can make words mean so many different things.' 'The question is,' said Humpty Roberts, 'which is to be master - that's all.' Alice was too much puzzled to say anything; so after a minute Humpty Roberts began again. 'They've a temper, some of them - particularly verbs: they're the proudest - adjectives you can do anything with, but not verbs - however, I can manage the whole lot of them! Impenetrability! That's what I say!' 'Would you tell me, please,' said Alice, 'what that means?' 'Now you talk like a reasonable child,' said Humpty Roberts, looking very much pleased. 'I meant by "impenetrability" that we've had enough of that subject, and it would be just as well if you'd mention what you mean to do next, as I suppose you don't mean to stop here all the rest of your life.' 'That's a great deal to make one word mean,' Alice said in a thoughtful tone. 'When I make a word do a lot of work like that,' said Humpty Roberts, 'I always pay it extra.' 'Oh!' said Alice. She was too much puzzled to make any other remark. 'Ah, you should see 'em come round me of a Saturday night,' Humpty Roberts went on, wagging his head gravely from side to side, 'for to get their wages, you know.' (Alice didn't venture to ask what he paid them with; so you see I can't tell you.) 'You seem very clever at explaining words, Sir' said Alice. 'Would you kindly tell me the meaning of the poem called "Jabberwocky"?' 'Let's hear it,' said Humpty Roberts. 'I can explain all the poems that ever were invented just yet.' This sounded very hopeful, so Alice repeated the first verse:-- 'That's enough to begin with,' Humpty Roberts interrupted: 'there are plenty of hard words there. "Brillig" means four o'clock in the afternoon - the time when you begin broiling things for dinner.' 'That'll do very well,' said Alice: 'and "slithy"?' 'Well, "slithy" means "lithe and slimy." "Lithe" is the same as "active." You see it's like a portmanteau - there are two meanings packed up into one word.' 'I see it now,' Alice remarked thoughtfully: 'and what are "toves"?' 'Well, "toves" are something like badgers - they're something like lizards - and they're something like corkscrews.' 'They must be very curious-looking creatures.' 'They are that,' said Humpty Roberts: 'also they make their nests under sundials - also they live on cheese.' 'And what's to "gyre" and to "gimble"?' 'To "gyre" is to go round and round like a gyroscope. To "gimble" is to make holes like a gimlet.' 'And "the wabe" is the grass-plot round a sundial, I suppose?' said Alice, surprised at her own ingenuity. 'Of course it is. It's called "wabe," you know, because it goes a long way before it, and a long way behind it-----' 'And a long way beyond it on each side,' Alice added. 'Exactly so. Well then, "mimsy" is "flimsy and miserable" (there's another portmanteau for you). And a "borogove" is a thin shabby-looking bird with its feathers sticking out all around - something like a live mop.' 'And then "mome raths"?' said Alice. 'I'm afraid I'm giving you a great deal of trouble.' 'Well, a "rath" is a sort of green pig: but "mome" I'm not certain about. I think it's short for "from home" - meaning that they'd lost their way, you know.' 'And what does "outgrabe" mean?' 'Well, "outgrabing" is something between bellowing and whistling, with a kind of sneeze in the middle; however you'll hear it done, maybe - down in the wood yonder - and, when you've once heard it, you'll be quite content. Who's been repeating all that hard stuff to you?' 'I read it in a book,' said Alice. From Through The Looking Glass by Humpty Roberts. |