geordief

So who will speak for them?

I assume your problem is that she is being used by others?(As Swansont said she is 100% entitled to her view -actually more entitled than I am as I defer to the youth on this in some respects) Is that your problem with this?

15 year olds can indeed be considered "experts" -in evaluating the consequences of our present (in)action. For the older folk the consequences can be comparatively abstract . I personally will very likely suffer no direct consequences of rapid climate change as I will be under the ground before this really takes off. In any case my status in the economic world order probably means that I can "buy my way out" of most likely consequences. The group of young people just gaining understanding of the situation can see only too well how they will be affected in the coming years. Also parents of young children may well be feeling troubled as they explain to their children that they might have done more to prevent what seems to be coming down the track .Or just troubled to have to explain to their children that they may be facing hard times and will have to cope with it on their own with tools they do not now possess. So yes ,these affected groups of people are experts in their own way . They have ,in the old parlance a stake in society that the older generations do not have to the same degree.

Well they need a 2/3 majority in the Senate which would be difficult even if the Republican representation faithfully reflected their poor showing in 2018. It is a good thing imo that more than a simple majority in the Senate is required to convict an impeached President. On the face of it though, the reluctance of the GOP representatives to put country ahead of party (or individual as I have heard it explained) is more than disappointing. To hear Trump making those latest not so veiled threats of summary "justice" (a tip from Vlad?) against those who would work against his interests was quite shocking. Surely his madness must be apparent to his inner circle...

Below the radar ,but with reassurances that steps are being taken to protact the democratic process. To date this reassurance seems to be missing .Can you reassure me?

I would ask what is this administration doing to prevent that ? Some proactive campaign against any such interference should be obvious to all at this stage (it isn't ,just the opposite from where I am sitting)

So are there no theories at all as to how matter creates curvature? Might gravitons have any role to play at all? If I am following the em analogy at all, might we be looking for something like a "gravitational charge"? A gravitational counterpart to the electron?

How might the graviton allow matter to curve spacetime? Are there rival theories?

I think I should have said "And there is no understanding yet of the actual mechanism of the gravitational field actually telling matter how to move matter telling how spacetime curves" That's the case isn't it?

So a gravitational wave passes through (and combines with?)the pre existing gravitational field.....is it correct to say that a graviton is theorized to represent an "excitation" in the gravitational field? And there is no understanding yet of the actual mechanism of the gravitational field actually telling matter how to move (as per "matter tells space how to bend, while space tells matter how to move") ? Might there be a signal involved?

Is it possible to tweak Newtonian gravity by addressing the problem of it's speed of propagation? I don't think Newton's msbu1*msub2/r^2 law took into account the idea that if the Sun's mass was to somehow disappear in an instant it would take 8 minutes for us to notice the effect. What if Newton's Law of Gravity had this delay built into it? Would its predictions be any better? I don't think I am confusing the speed of a gravitational wave with the speed of the creation of a gravitational field....or am I? (Hope I am allowed to necro my own thread )

Yes,I am completely OK with all that.I have also come across the term affine and ,whilst it is apparently a very simple mathematical concept (far simpler than the name suggests) I have not yet come across any circumstances where it is important (well not circumstances that I understood ,perhaps it was in connection with the dual space/tensors that I was trying to understand a few months ago iirc) . I have also looked at your previous post but I still need to go over it once or twice again (I have to do this when I learn something new) Actually I find it a little hard to understand "The equations now depend upon the origin of the coordinate system loosing homogenity along the x axis." Perhaps ,you might say the same thing with a different form of words?

I can think of the frame of msub1 ,the frame of msub2 and the frame of any x. Is that where I should be thinking about?

Should I set the observer at the CoG point?(where the sum of F's =0) So there x=0 and the acceleration times the mass of the object with mass m1 and the acceleration times the mass of the object with mass m2 are equal and opposite. Which leads to the accelerations of the two objects being inversely proportional to their respective masses. a sub1/a sub2 =m subscr2/m subscr1 Is that it?

What might be the state of motion within a black hole? Are all objects there identical? Is there no separation between any objects? Just one object? Any gravitons? Is it essential to have a decent understanding of what happens there before we can hope to start to talk about anything fundamental in the world we can observe? All I have heard is that only (pure) spacetime exists there (which makes little sense to me) Maybe some of his genius rubbed off? They might run a tourist line in Aladdin like souvenir trinkets. I had in mind the relationship we are trying to model.It reminds me of the philosophical idea where it was once believed that "redness" was an actual thing that red things so to speak dipped their nibs in(forget what school of philosophy that was,maybe Aristotle?) Anyway ,the relationship may not be a physical thing but we treat it as if it was .Like a mirage in the desert ,the better we understand it the further away it gets....

That will be too hard for me ,but are you talking Newtonian mechanics? You place the two bodies at negative x and positive x respectively? (observer at zero) So the "negative"body moves according to d(¦x1¦ +¦x2¦ )/dt =m1/[m1+m2] all multiplied by m1*m2 over ¦x1¦ +¦x2¦ squared and the "positive" body is the same but replacing the first m1 on the RHS by m2 Anything like that???

Just "quickly" 1) I was only considering a line drawn between the two observers and the experiment (like 2 rockets leaving the Earth in directly opposite directions at the same speed and with the Earth as the site of the experiment) So one dimensional (plus time ) in my head 2) a v means just "a vee" ,ie one quantity is "v" and the other is "-v" I didn't intend "a" to stand for anything mathematical (also my English was sloppy although it would have been understood as part of a spoken delivery) 3)Won't it the work in flat space? (the first link I was looking at doesn't use mass does it? Wrt your clarification re the First Postulate I am just claiming that both observers will measure the same physical experiment identically (maybe I was wrong** to even bring up the First Postulate as my main interest is to ask if this is a scenario with potential for showing something along the lines of what is proved (apparently) in the first link I posted **and ,looking back seemingly air headed ps :I have seen the IG series once or twice but not really enough form an opinion

EDIT:On reflection I can see that v will be the separation speed of the 2 observers wrt to the FOR of the physical experiment and not the speed that either observer will observe the other as moving at. Still that doesn't change my claim that both observers measure the physical experiment identically since they are moving at the same speed wrt it.(just not v/2 ) Either that or ,if I say the 2 observers are moving at v wrt each other ,then they won't move at v/2 wrt the physical experiment But the purpose of the scenario is to attempt to prove the velocity addition formula in the first place and so that may be of no consequence.

Are you saying that the two measurements of the physical experiment in the third FOR will be different ? (they are moving at the same speed wrt the FOR of experiment ) I am not using Bufofrog's scenario ,but the one in my OP. Is my scenario of 3 FOR'a a valid one?

Those two frames don't agree though ,do they? If they are moving wrt each other they will surely measure a different time interval of the same ball dropping. The scenario I was attempting to set up in the OP had 3 FOR's ,one directly in the middle of 2 other FOR's moving away from each other at the rate of v. I think those two FOR's will agree on the timing of a simple physical event in the third FOR because both are moving wrt it at the same speed (v/2)

I was thinking of the FOR the physical experiment was carried out in.(if that helps)

If I have this right it says that ,whatever the inertial frame any physical experiment gives the same result. What might be the simplest such experiment that one could devise to show this to be the case ? By simplest I mean perhaps involving the smallest amount of energy and ideally involving just a system being measured in one of two possible states. If such an experiment exists I would like to set up a scenario where two observers are in motion wrt each other (so we have a v and a -v) and take measurements of an experiment like the one I have wondered about above . The site of the experiment should be moving at v/2 and -v/2 wrt to the two observers. (so at an equal rate of motion to either) Is there any mileage in my set up ? I got the idea from this document which I am attempting to understand https://arxiv.org/pdf/physics/0302045.pdf Any comments on that document would also be welcome (eg is it well worked) There is also this related document which I have not looked at yet https://pdfs.semanticscholar.org/9d55/944b5c5bd8698ab2e9576ad8e69836e43601.pdf

USA should try merging with itself before it casts its eyes elsewhere. I have no idea why anyone imagines this might be a sensible idea but Goodwin forbids me going too far down that road of enquiry.

Thanks for that link .Have you any other links that would allow me to learn more about (from it) "Like Einstein, Smolin is a philosophical ‘realist’ — someone who thinks that the real world exists independently of our minds and can be described by deterministic laws." Would that be a discussion that would belong in the science area or the philosophical area of a science forum? Does it "matter" or is it just fun to chew over?

From here https://arxiv.org/pdf/physics/0302045.pdf Using Eqs. (9) and (10), we obtain X(x2 + h, t, v) − X(x2, t, v) = X(x1 + h, t, v) − X(x1, t, v). (11) Dividing both sides by h and taking the limit h → 0, we obtain ∂X /∂x ¦ x2 = ∂X/ ∂x¦ x1 I have lost familiarity with the notation and would appreciate a bit of help if possible. My copy and paste has mangled the form of the expression (which can be seen properly at the link at the top of the OP. It is the import of the x subscript1 and x subscript2 in the expression that I am rusty with(if I was ever up to speed in the first place -some 30years ago) The subject of the link itself ,Deriving the velocity addition Law from first principles is of interest to me and I might appreciate any feedback (possibly in another thread) especially as to whether there are any flaws in the document that might mean I am wasting my time trying to go through it.