Newton's Revised Gravity Theory

[Leontarion]

Here is an article about my revised Newton's gravity formula

[DrKrettin]

Here is an article about my revised Newton's gravity formula

 

You seem to have a problem with the concept of infinity. Your basic argument says that if M exerts a force at infinity, then M must be infinite. That is true, but Newton's formula does not say that, so why object to it?

[OceanBreeze]

. . . if M exerts a force at infinity, then M must be infinite. That is true  . . .

 

Is that true? The force would become infinitesimally small at an infinite distance, but I see no need for M to be infinite?

 

By the way, I am only responding to what you wrote here, I have not gone to the link in the OP. I think he should post his idea here and not a link.

Edited June 22, 2017 by OceanBreeze

[exchemist]

Is that true? The force would become infinitesimally small at an infinite distance, but I see no need for M to be infinite?

 

By the way, I am only responding to what you wrote here, I have not gone to the link in the OP. I think he should post his idea here and not a link.

I think he's right.

 

Surely the limit of F = GMm/r²,  as r -> ∞ is zero, is it not? 

 

Agree this blighter should post his ideas on the forum though.

Edited June 22, 2017 by exchemist

[OceanBreeze]

I agree with the limit you posted but at the same time it is usual to assume the gravitational field of any object extends to infinity. Therefore, it can exert a force if there is a mass at infinity (a ridiculous statement, to be sure) without the mass being infinite.

 

On second thought, this is a meaningless discussion, I think.

[Leontarion]

r can not be zero because F=GMm/r^2 F becomes infinity or mathematically is impossible. Mathematically ex one mass m can act to infinity but practically is true? I remember one teacher was saying us that mathematically an electron can act force to other electron to infinity but practically the infinity can be some cm where the force is zero. Personally i don't believe that ex an electron can act to infinity to an another electron, is out of logic.

Edited June 22, 2017 by Leontarion

[OceanBreeze]

r can not be zero because F=GMm/r^2 F becomes infinity or mathematically is impossible.

 

Well, that is the opposite problem to what we were discussing. We were talking about r going to infinity, not zero.

However, since you bring it up, the zero distance is not a real problem because in order to have mass, a particle must also have some spatial dimension and therefore two such particles cannot have zero separation and the problem cannot arise.

 

Two point particles with zero mass, such as photons, can be in the same place with zero separation, but having no mass there is also no gravitational force, so no problem to solve.

 

Mathematically ex one mass m can act to infinity but practically is true? I remember one teacher was saying us that mathematically an electron can act force to other electron to infinity but practically the infinity can be some cm where the force is zero. Personally i don't believe that ex an electron can act to infinity to an another electron, is out of logic.

 

 

Talking about infinite distances is not always logical!

[exchemist]

r can not be zero because F=GMm/r^2 F becomes infinity or mathematically is impossible. Mathematically ex one mass m can act to infinity but practically is true? I remember one teacher was saying us that mathematically an electron can act force to other electron to infinity but practically the infinity can be some cm where the force is zero. Personally i don't believe that ex an electron can act to infinity to an another electron, is out of logic.

"Act to infinity" is meaningless. The force tends to zero as r tends to infinity. The same goes for the force of repulsion between 2 electrons. You really need the mathematical concept of limits: https://en.wikipedia.org/wiki/Limit_(mathematics)  to analyse such situations correctly.

Edited June 22, 2017 by exchemist

[OceanBreeze]

"Act to infinity" is meaningless. The force tends to zero as r tends to infinity. The same goes for the force of repulsion between 2 electrons. You really need the mathematical concept of limits: https://en.wikipedia.org/wiki/Limit_(mathematics)  to analyse such situations correctly.

 

Exactly. I agree it is meaningless, so why do you think it is right to say that M must be infinite?

[Leontarion]

How Newton found this formula? Nobody said to us, i suppose is from experimental values and from that values the best formula which descripes the values is F=GMm/r^2 but this

does not mean that is right because theoretically we can find unlimited approximated formulas which descripe our values. Also there is a book about this, "What is this thing we call science" which says the weakness which science has to find the equation of truth. In physics we have many formulas which in reality are approximations ex F=ma (in lab is the equation of truth and 100% right)  and when a factor changes (u starts to be very great) then the Newton formula is wrong and general relativity is right Frel=F(newton).γ (for example) but even general relativity starts to be wrong when other factors change e.t.c SO what is this thing we call science? We can make science and find the formulas of truth just from experimental values? If i am wrong then why every time a theory collapse and starts something new? Is because we are more near to truth or because the methods we use to make science are just wrong or just approximations. Is not so easy to answer as you think.

Edited June 22, 2017 by Leontarion

[Leontarion]

I assert that if we think in general relativity a mass must have infinity mass so to can curve/fold the spacetime to infinity so to have the ability to act in infinity or if the spacetime is not empty and is a new material with new elasticity k then the elasticity must be infinity so to can stretch the spacetime to infinity and so the Newton's law to be right. When a formula mathematically has infinities or not accepted solutions like f=GMm/0 then something is wrong because a formula for me must have mathematical and physical meaning. 

[Leontarion]

The strange for me is not to find a new approximative formula but to find the formula of truth.

[OceanBreeze]

The strange for me is not to find a new approximative formula but to find the formula of truth.

 

There is no absolute truth in science. Approximations are the best we can do. The value of G, for example, is only known to three significant digits! Compare that to pi, that has now been calculated to millions of significant digits.

[OceanBreeze]

Exactly. I agree it is meaningless, so why do you think it is right to say that M must be infinite?

 

Just to be clear, I wasn't looking for an argument with you; I was interested in why you said that, because you are usually right, and I cannot see why M has to be infinite?

[DrKrettin]

Just to be clear, I wasn't looking for an argument with you; I was interested in why you said that, because you are usually right, and I cannot see why M has to be infinite?

 

In his link, the OP said that to exert a force at infinity, the mass must be infinite, therefore Newton's equation must be wrong. He doesn't seem to understand the mathematical concept of infinity, and thinks the force there could be non-zero. (That's my understanding of what he has written in the link). I ventured to say that it was true that the only way a mass would exert a force at infinity was with infinite mass. (Assuming Newton's 1/r^2)

 

However, I have forgotten how to calculate the limit of M/r^2 as r tends to infinity, and am wondering whether this expression could only be non-zero if M is infinity squared. But the whole argument is pointless, because I can't see the problem which he has with Newton's Law, and he does not explain it. 

Edited June 22, 2017 by DrKrettin

[exchemist]

Exactly. I agree it is meaningless, so why do you think it is right to say that M must be infinite?

Oh, that was just because you suggested an infinitesimally small force would remain at infinity.

 

I take "infinitesimal" to mean arbitrarily small, but non-zero quantity, on its way to becoming zero in the limit,  but not yet at that limit.

 

To have a non-zero force at infinity would require infinite mass. That is why I prefer to express the situation as one tending to zero as the other tends to infinity. 

[DrKrettin]

I take "infinitesimal" to mean arbitrarily small, but non-zero quantity, on its way to becoming zero in the limit,  but not yet at that limit.

 

To have a non-zero force at infinity would require infinite mass. That is why I prefer to express the situation as one tending to zero as the other tends to infinity. 

 

That was the point I was trying to make.  And yes, the standard definition if infinitesimal is vanishingly small but still non-zero.