Gravity never zero

[OnlyMe]

You would think they know better!

For the momentum to increase more than the change in velocity can only be explained by the change in the mass
Momentum = MV, if momentum goes up but the velocity doesn't change much, that implies the mass has increased.
That's my way of thinking.

Momentum = MV or p = mv is valid for Newtonian dynamics. The proper form within the context of SR is, $$ p = mv\gamma$$, where $$\gamma = \frac{1}{\sqrt{1-(v^2/c^2)}$$.

It is becomiming very difficult to stay on track. Too much of what is being posted involves pre-SR formulas and Netonian logic, nether of which are accurate within modern contexts. While this is OK for the slow velocities associated with everday life. Many of the formulas and pre-SR Newtonian logic, is no longer an accurate description of experience, when the discussion involves relativistic velocities.

 

[Robittybob1]

Momentum = MV or p = mv is valid for Newtonian dynamics. The proper form within the context of SR is, $$ p = mv\gamma$$, where $$\gamma = \frac{1}{\sqrt{1-(v^2/c^2)}$$.

It is becomiming very difficult to stay on track. Too much of what is being posted involves pre-SR formulas and Netonian logic, nether of which are accurate within modern contexts. While this is OK for the slow velocities associated with everday life. Many of the formulas and pre-SR Newtonian logic, is no longer an accurate description of experience, when the discussion involves relativistic velocities.

So what is that type of momentum called? Relativistic momentum? $$ p = mv\gamma$$, where $$\gamma = \frac{1}{\sqrt{1-(v^2/c^2)}$$.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html
"which is the ordinary definition of momentum with the mass replaced by the relativistic mass. "

 

[OnlyMe]

So what is that type of momentum called? Relativistic momentum? $$ p = mv\gamma$$, where $$\gamma = \frac{1}{\sqrt{1-(v^2/c^2)}$$.

It is just momentum.

$$ p = mv$$ is the formula for momentum in Newtonian dynamics. That is where space is fixed and there is no speed of light limit.

When Einstein introduced special relativity and the speed of light, as a universal constant.., and speed limit the formula became $$p = mv\gamma$$, where $$\gamma = \frac{1}{\sqrt{1-(v^2/c^2)}$$.

The Lorentz factor acts as the speed limit for velocity.

I think that maybe some of the confusion actually comes from understanding that in the equation $$E = mc^2$$, $$E$$ is the total rest energy of the involved mass. To be consistent with the evolution of our knowledge about particle physics it really should be, $$E_o = mc^2$$, where $$E_o$$ denotes the total energy of the rest state of the mass and does not include any kinetic energy associated with velocity. Velocity does not change the object's mass, just its total energy and momentum.

I keep trying to point out that "relativistic mass" is really just momentum.

This is another quote from Okun,

The notion of the dependence of mass on velocity was introduced by Lorentz in 1899 and then developed by him and others in the years preceding Einstein's formulation of special relativity in 1905, as well as in later years. The basis of this notion is again the application of the non relativistic formula p = mv in the relativistic region, where (as we know now) this formula is not valid.​

What he is saying is that they were applying a formula which was valid for Newtonian dynamics, within the context of SR where it was no longER always true. $$p = mv$$ only works within SR in the very localized scale of everday life and velocities of the late 1800's. As soon as special relativity departs from the Newtonian view the formula no longer works.

The idea that mass and velocity were connected is way old and is not confirmed by experiment. Still even many physists will use terms like relativistic mass, if you question them they will generally explain it as momentum. Re-read the quote from a few posts back from the LHC Machine Outreach FAQ. They say relativistic mass and then describe it as momentum.

Once a term gets a footing in language it becomes very difficult to let it go, even when it adds more confussion that clarity. I have the same problem. I have referred to relativistic mass repeatedly in other threads and I know it can be misleading.

 

[Robittybob1]

I'll reserve my decision till I get more information on the topic. At the moment I still think the momentum rises for both velocity and mass increases. Rather than just the momentum increasing as such.

What is the experiment referred to here: "The idea that mass and velocity were connected is way old and is not confirmed by experiment"?

 

[hansda]

I have no problem thinking that matter with additional Energy has addition mass, additional inertia, and additional kinetic energy if there is motion involved.
Extra mass implies extra weight in a gravitational field.
I have no problem with any of these, so why do you?

There is no longer the proportional relationsip F = MA when the velocities gets higher The velocity stops rising as rapidly, like as if the mass is increasing.

You are just not considering the dragging effect of frame-dragging , which happens at high momentum .

So, F = MA ; can be rewritten as F = MA + dF , where dF is the force generated due frame-dragging or space-dragging .

This dF is dependant upon speed or momentum . More the speed , more the momentum , more the dragging effect , more is dF .

So, at higher velocities , F - dF = MA ; Newton's equation still holds .

Due to increase of dF at higher velocities , it seems as if the mass is increasing .

As I asked before "Well would you like to offer an explanation why it becomes impossible to accelerate a mass beyond the speed of light, using the terms rest mass, momentum and velocity please? "

Just consider the equation : F - dF = MA ; where dF is dragging force and a function of speed .

 

[hansda]

You would think they know better!

For the momentum to increase more than the change in velocity can only be explained by the change in the mass
Momentum = MV, if momentum goes up but the velocity doesn't change much, that implies the mass has increased.
That's my way of thinking.

You can not apply momentum externally . You can only apply energy .

Normally with more energy , momentum is more , velocity is more .

But with more energy , if the velocity is not increasing ; this can not be concluded that mass is increasing .

Along with the conservation of momentum , conservation of energy also should be considered .

 

[Robittybob1]

...
Normally with more energy , momentum is more , velocity is more .

But with more energy , if the velocity is not increasing ; this can not be concluded that mass is increasing

It can't be concluded that mass is increasing, but that is why they call it relativistic mass, as a way for accounting for the additional momentum and the energy. They can only account for it if the mass increases.
I'm still looking for that "experiment"that proves this otherwise.

 

[Robittybob1]

You are just not considering the dragging effect of frame-dragging , which happens at high momentum .

So, F = MA ; can be rewritten as F = MA + dF , where dF is the force generated due frame-dragging or space-dragging .

This dF is dependant upon speed or momentum . More the speed , more the momentum , more the dragging effect , more is dF .

So, at higher velocities , F - dF = MA ; Newton's equation still holds .

Due to increase of dF at higher velocities , it seems as if the mass is increasing .

Just consider the equation : F - dF = MA ; where dF is dragging force and a function of speed .

Framing dragging for some reason conjures up ideas like friction, but it is a reactive force in that formula of yours, but could you use dF in another way to show frame draggingg raises the momentum?
There seems to be conserved Energy and Momentum, unlike friction which just loses energy as heat.

 

[hansda]

It can't be concluded that mass is increasing, but that is why they call it relativistic mass, as a way for accounting for the additional momentum and the energy. They can only account for it if the mass increases.

They are just not considering the frame-dragging effect of space .

I'm still looking for that "experiment"that proves this otherwise.

I think here the experiment which i suggested earlier , can be considered .

 

[Robittybob1]

They are just not considering the frame-dragging effect of space .

I think here the experiment which i suggested earlier , can be considered .

You are right it hasn't been considered, but they know the momentum is conserved so make up a formula where Frame Dragging (FD) adds to the momentum.

 

[hansda]

You are right it hasn't been considered, but they know the momentum is conserved so make up a formula where Frame Dragging (FD) adds to the momentum.

What about 'conservation of energy' ?

 

[hansda]

Framing dragging for some reason conjures up ideas like friction, but it is a reactive force in that formula of yours, but could you use dF in another way to show frame draggingg raises the momentum?

Consider my earlier equations about dF .

dF = F1 - F2 = Gm1m2 ( 1/x^2 - 1/(x+dx)^2 ) ;

dF = Gm1m2/(x^2 * (x+dx)^2) * (x+dx-x)(x+dx+x) ;

dF = Gm1m2/(x^2 * (x+dx)^2) * dx(2x + dx) ;

dF approx= Gm1m2/x^4 * 2xdx ;

dF approx= Gm1m2/x^2 * 2dx/x ;

dF approx= F1 * 2dx/x ;

dx = v * dt , where v is relative velocity between m1 and m2 at a distance x .

So,

dF approx= F1 2 v dt/x ;


From the above equation , it can be seen that as v rises dF rises . So, dragging depends upon momentum .

There seems to be conserved Energy and Momentum, unlike friction which just loses energy as heat.

 

[Robittybob1]

I might have to get you to go through that line by line for I don't know about algebra.

Start from the two equations you use in the first place. please.

 

[Robittybob1]

Consider my earlier equations about dF .

dF = F1 - F2 = Gm1m2 ( 1/x^2 - 1/(x+dx)^2 ) ;

dF = Gm1m2/(x^2 * (x+dx)^2) * (x+dx-x)(x+dx+x) ;

dF = Gm1m2/(x^2 * (x+dx)^2) * dx(2x + dx) ;

dF approx= Gm1m2/x^4 * 2xdx ;

dF approx= Gm1m2/x^2 * 2dx/x ;

dF approx= F1 * 2dx/x ;

dx = v * dt , where v is relative velocity between m1 and m2 at a distance x .

So,

dF approx= F1 2 v dt/x ;


From the above equation , it can be seen that as v rises dF rises . So, dragging depends upon momentum .

Your first equation was F - dF = MA (dF is the force provided by frame dragging).
Then you say dF = F1 - F2 (so I take that to mean it is the difference between two undefined forces?)
Then you use something like the equation for the force of gravitation
dF = Gm1m2 ( 1/x^2 - 1/(x+dx)^2 )
You don't define X or dx? and we don't find the equation having the same form as Newton Gm1m2/r^2 show me how you go from one to the other.

 

[hansda]

Your first equation was F - dF = MA (dF is the force provided by frame dragging).
Then you say dF = F1 - F2 (so I take that to mean it is the difference between two undefined forces?)
Then you use something like the equation for the force of gravitation
dF = Gm1m2 ( 1/x^2 - 1/(x+dx)^2 )
You don't define X or dx? and we don't find the equation having the same form as Newton Gm1m2/r^2 show me how you go from one to the other.

I already defined F1 , F2 , X , dx in my earlier post # 212 .

I am also posting them here :

Consider the frame-dragging effect is taking place at distance 'x' between two masses m1 and m2 . Due to this frame-dragging there is a space-shift by the distance 'dx' .

At a distance x , the force F1 = G m1 m2 / x^2 .

At a distance x + dx , the force F2 = G m1 m2 / (x+dx)^2 .

This difference of force dF = F1 - F2 ; can be considered as the force generated due to the effect of frame-dragging .

 

[wlminex]

IMO . . . gravity is an intrinsic characteristic of mass. If there is no mass present . . . there is no gravity . . . If we are contemplating a region of space where there is NO mass. However (IMO) if some component (or all?) of space is imbued with energy (only, to the exclusion of mass - visualization here) the gravity component is necessarily (by classical definition) nonexistent. Another HOWEVER . . . the energy component CAN become mass . . . thereby 'creating' a cumulative gravity component.

 

[keith1]

Gravity force occurs or emanates between two mass object centers, and this is not necessarily saying that the center of mass is somehow akin to gravity.

It would seem more apparent that "space" is trying to "get out of the way"of being "caught in between" two or more mass objects.

This "moving of space" is a minimal force. Park your gravity detector out between two weighted steel marbles, and you will likely not detect anything. Drive your detector out between two gravitational singularities (black holes), and you may get a show.

 

[Robittybob1]

I already defined F1 , F2 , X , dx in my earlier post # 212 .

I am also posting them here :

I can see
"At a distance x , the force F1 = G m1 m2 / x^2" that is Newton's gravitational force equation .

"At a distance x + dx , the force F2 = G m1 m2 / (x+dx)^2" same equation at a larger distance "x+dx" .

The next bit is the bit that does not follow logically to me: "This difference of force dF = F1 - F2 ; can be considered as the force generated due to the effect of frame-dragging".

Can you explain your logic please?

 

[OnlyMe]

Where F1 = G m1 m2 / x^2 and F2 = G m1 m2 / (x+dx)^2, dF = F1 - F2 = -dx

Which Hansda assumes represents the frame dragging effect. You could think of that as a negative vector force.., resisting the motion of matter/mass....

However, it does not seem from what I have read about frame dragging, that it follows the same inverse square relationship to mass and distance that a gravitational potential does. Though frame-dragging does come from Einstein's field equations, I have seen nothing (that I understand) that suggests that it mirrors gravitational potential in a one to one relationship.

Even though GR describes gravity as a curvature of spacetime, it does not explain how mass and space interact to curve spacetime, only that they do. Similarly, the root mechanism of frame-dragging remains unexplained.

It does appear to me that where gravitational potential can be considered a weak force, emerging from the presence of mass in spacetime.., the frame-dragging effect seems to emerge from a very weak interaction involving the motion of mass in spacetime.

It is far easier to detect and measure gravitational potentials, than any associated frame-dragging effect.

There is another error in Hansda reasoning and formula, which lies in the fact that frame-dragging is an effect within GR, not Newtonian Mechanics. The formulas he is beginning with are not relativistic except within a locally flat weak gravitational potential. Frame-dragging itself is an artifact of the curvature of space and the dynamic nature of spacetime within GR.

That said, there does seem to be similarities between frame-dragging and inertia, which when viewed within the contex of the principle of equivalence, would tie it in some fashion to gravity.

Though, I am as yet unconvinced, I have read and been reading some of the past attempts to explain inertia, as an emergent phenomena involving the motion of matter through the vacuum energy of otherwise "empty" space. It maybe that frame-dragging emerges from this interaction in a similar way. If so only as conditions involving mass and velocities, that depart from the flat space and time of Newtonian dynamics and begin to be described within the context of SR and GR, would the frame-dragging effect become significant and within our ability to even detect it.

This all really remains speculation. Though we have confirmation of frame-dragging associated with the angular momentum of a gravitationally significant mass, we have no independent confirmation associated with linear momentum, though it is predicted. And as mentioned earlier the underlying mechanism(s) are, as yet unknown.

 

[wellwisher]

One affect that gravity creates, which is not included in GR, is pressure. Gravity creates two affects, one is the changing of space-time and the other is the changing of distance between objects; pressure. For example, neuron density actually has all the original matter physically closer than it had been. This is not due to reference effects based on contracted space-time. That is a separate thing.