  City-Data Forum does anyone else know Newton's law of gravity is wrong. (theory, universe)
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 7,249 posts, read 5,705,717 times Reputation: 7963

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 You haven't followed but don't worry.
I haven't followed because what you posted makes no sense.
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 1/d/d is a rate of acceleration.
No it isn't. It doesn't even have the right units.

Go read Principia, or better yet, pick up an introductory physics book and start at the beginning. The gravitation law is empirical. We use it because it gives the right answer.

You seem to be taking what is fundamentally a two body problem and trying to reduce it to one body.

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 Every particle pulls every other particle with a force equal to the product of their masses etc. If true this means every particle has the same gravity.
I'll ask again, do you also reject Coulomb's law? Do you think every charge must be the same because they exert a force on each other that is proportional to the product of the two charges? That is clearly nonsense.

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 I know Newton's law of gravity is in invalid.
No. You think it is invalid because you don't understand what it's telling you.

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 Perhaps the opening post was a little to confronting.
It wasn't "to confronting." It was simply wrong.  Location: Itinerant 6,787 posts, read 4,375,882 times Reputation: 5108
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 Originally Posted by manygeese You haven't followed but don't worry. 1/d/d is a rate of acceleration.
No it's not, acceleration is (distance unit)/(time unit ^2) your 1/d/d (which I assume d is distance) has no time unit, thus cannot be an acceleration of any form, because you have an ordinal (1) and two distances.

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 Originally Posted by manygeese This rate increases and decreases as M increases and decreases. Thus M/d/d is a measure of a rate of acceleration.
What is a rate of acceleration? do you mean the third derivative of distance WRT time? Acceleration his agnostic of mass, so why would mass (and I assume mass is the unit of M) play any role in that?

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 Originally Posted by manygeese I don't think you quite know how Newton put his law together. If you do, go for it. Explain what you know about how he formulated the thing.
Which law? The law of Newtonian Gravity, or one of his Laws of Motion?

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 Originally Posted by manygeese I accept Newton's third law. But don't accept the moon 'pulls' the earth as much as the earth 'pulls' the moon as it must if Newton's law of gravity, per chance was valid.
So then you're denying Newtons third law by definition, it's not optional, if it holds true it holds true in all eventualities. Any force will result in an equal and opposite opposing force, thus if the moon is pulled towards the earth with a big cable, there is an equal and opposite force pulling the earth to the moon. The Third Law is agnostic of what is causing the force, just that it states that if there is a force, then there is an equal and opposite reaction to that force.

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 Originally Posted by manygeese I know Newton's law of gravity is in invalid. This was just an inquiry as to whether anybody else did. Perhaps the opening post was a little to confronting. Apologies for that. Every particle pulls every other particle with a force equal to the product of their masses etc. If true this means every particle has the same gravity. Newton's law of gravity is clearly ill founded. Not much else to it.
Every particle has a gravitational "potential", that is classically expressed as G (m/R^2), where "m" is the mass of the particle, which means it has an attractiveness that is proportional to its inertial mass, however an attractive force requires a second body (and a distance between them) to provide a second inertial mass to calculate that force. It's only when the force becomes more than negligible than it becomes interesting, and at that point your hypothesis is ascribing intelligence so that the apple in your example knows that it's an apple, so exerts low or no force on the earth, but the earth knowing that it's the Earth still exerts the expected force on it as say a book of the same mass.

By inference because the Apple is supermassive in comparison to a hydrogen atom, the Apple chooses to exert is ultimate potential against the hydrogen atom, while the lowly hydrogen atom does not, however the hydrogen atom being supermassive in comparison to a passing photon unleashes its full gravitational potential against the photon, who being a photon has minimal mass (defined only by its energy) and thus meeky submits to the gravity of the hydrogen atom (unless of course the photon has a huge quanta of energy and exceeds the mass of the hydrogen atom, in which case the situation would be reversed). On the larger scale, the earth knows it cannot exert it's full gravitational force against the sun, however the sun exerts it full force against the earth, yet the Sun itself does not exert it's full force against the attraction of the Galactic Core, yet the Galactic core can do so.

This is the logical conclusion of your hypothesis. Thanks for sharing.  manygeese Location: Riachella, Victoria, Australia 359 posts, read 563,594 times Reputation: 378
Let's go back to what is not understood.

Acceleration due to gravity is proportional to 1/d/d where d is distance from the centre of gravity source.

That's the inverse square law.

Therefore 1/d/d is a measure of acceleration due gravity at d.

For any point in the earth's gravity field a1 x d1 x d1 = a2 x d2 x d2 where d1 and d2 are distances from the centre of the earth and a1 and a2 are rates of acceleration due to gravity at d1 and d2 respectively.

That's inarguable. Any spherical area around the centre of a gravity field is an inverse measure of the rate of acceleration towards the centre of the gravity field at the distance the area is being measured (from the centre of the gravity field). Don't worry about acceleration nominally being of different dimensions. That's just fact.

The inverse square law was derived from Kepler's third law and that's what the inverse square law tells us. 1/d/d is a measure of a rate of acceleration due to gravity.  manygeese Location: Riachella, Victoria, Australia 359 posts, read 563,594 times Reputation: 378
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 Originally Posted by Gungnir N Every particle has a gravitational "potential", that is classically expressed as G (m/R^2), where "m" is the mass of the particle, which means it has an attractiveness that is proportional to its inertial mass, however an attractive force requires a second body (and a distance between them) to provide a second inertial mass to calculate that force. It's only when the force becomes more than negligible than it becomes interesting, and at that point your hypothesis is ascribing intelligence so that the apple in your example knows that it's an apple, so exerts low or no force on the earth, but the earth knowing that it's the Earth still exerts the expected force on it as say a book of the same mass. By inference because the Apple is supermassive in comparison to a hydrogen atom, the Apple chooses to exert is ultimate potential against the hydrogen atom, while the lowly hydrogen atom does not, however the hydrogen atom being supermassive in comparison to a passing photon unleashes its full gravitational potential against the photon, who being a photon has minimal mass (defined only by its energy) and thus meeky submits to the gravity of the hydrogen atom (unless of course the photon has a huge quanta of energy and exceeds the mass of the hydrogen atom, in which case the situation would be reversed). On the larger scale, the earth knows it cannot exert it's full gravitational force against the sun, however the sun exerts it full force against the earth, yet the Sun itself does not exert it's full force against the attraction of the Galactic Core, yet the Galactic core can do so. This is the logical conclusion of your hypothesis. Thanks for sharing.

No worries but what I would like you to consider is the foundation of mathematical physics, that mass simultaneously exists in two forms. Inertial and gravitational.

When an exact equivalence is found between the two assumed types of mass, a true scientist should consider the distinct possibility that the two types are an academic misapprehension and that there is only the mass kind of mass.

Each type of mass is measured by some form acceleration or other. When they are found to be the same, why would a scientist conclude their is two types of mass. That's tied in with Newton's law of gravity being invalid but also getting away from it a bit to.  Location: Itinerant 6,787 posts, read 4,375,882 times Reputation: 5108
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 Originally Posted by manygeese Let's go back to what is not understood. Acceleration due to gravity is proportional to 1/d/d where d is distance from the centre of gravity source. That's the inverse square law. Therefore 1/d/d is a measure of acceleration due gravity at d. For any point in the earth's gravity field a1 x d1 x d1 = a2 x d2 x d2 where d1 and d2 are distances from the centre of the earth and a1 and a2 are rates of acceleration due to gravity at d1 and d2 respectively. That's inarguable. Any spherical area around the centre of a gravity field is an inverse measure of the rate of acceleration towards the centre of the gravity field at the distance the area is being measured (from the centre of the gravity field). Don't worry about acceleration nominally being of different dimensions. That's just fact. The inverse square law was derived from Kepler's third law and that's what the inverse square law tells us. 1/d/d is a measure of a rate of acceleration due to gravity.
Erm no the inverse square law was alleged to have been stolen from Robert Hooke, Keplers third law involves a cubic law (the square of the orbital period is directly proportional to the cube of the semi-major axis of it's orbit) how it was "proved" was to equate the square of the rotational period of two bodies divided by the cube of their semi-major axes and see whether they did indeed roughly equal, and it was found that four of Jupiter's moons did indeed roughly agree with this law. Many arguments exist about where the inverse square law comes from but Robert Hooke claimed at the time published he was responsible for it in relation to Newtons Law of Gravity, and there wasn't much arguing against it (Hooke was a serious heavyweight with the Royal Society at the time and had corresponded with Newton).

Meanwhile, the inverse square law relates to a force, not an acceleration, the acceleration is the physical response of an object to a resultant force and is also proportional to that objects instantaneous mass.

However your mention of Kepler did trigger a potential as to why you're confused, Keplers laws do not take into account that the focus of an orbital ellipse is at the barycenter of the two bodies, not at the center of mass of the larger body (as Kepler stated). Now as it happens the larger body also orbits, but with a much smaller orbit but still elliptical, and with a focus of the ellipse also at the barycenter of the two bodies, however with a large body (such as Jupiter) the barycenter of the two bodies is within the verge of the larger body (in this case Jupiter), so you can see how this confusion could occur in the 1600's.

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 Originally Posted by manygeese No worries but what I would like you to consider is the foundation of mathematical physics, that mass simultaneously exists in two forms. Inertial and gravitational. When an exact equivalence is found between the two assumed types of mass, a true scientist should consider the distinct possibility that the two types are an academic misapprehension and that there is only the mass kind of mass. Each type of mass is measured by some form acceleration or other. When they are found to be the same, why would a scientist conclude their is two types of mass. That's tied in with Newton's law of gravity being invalid but also getting away from it a bit to.
No mass does not exist in two forms, I don't know where you get that idea from. It exists as a single form, that form is the stress-energy-momentum tensor. When I use the term Inertial Mass, it means that within that inertial frame of reference the sum of all of the energy that is embodied within that object so described. Now since I mention the stress-energy tensor, I'll also point out that the EFE approximate to Newtons Gravity within weak gravitational fields, and low velocities much less than c. So Einstein himself agrees with Newton, as do many others who have worked in, and are working in this field.

The only way I could see you think that there are two "types" of mass is that you are confused about the actual classical gravity equation (m1.m2), that isn't two "types" of mass, it's two discrete masses, one from a body of mass m1, and one from a body of mass m2. Since the mass of body 1 generates a gravitational field that is independant of body 2, and body 2 does likewise, the force is discovered only when those two fields interact in a way that is non-negligible (i.e. body 1 and body 2 interact in a measurable fashion according to their fields). So for instance how the earth orbits the sun (which is non-negligible), but not how I'm affected by, or how I affect the Large Magellanic Cloud (since this would be negligible).  manygeese Location: Riachella, Victoria, Australia 359 posts, read 563,594 times Reputation: 378
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 Originally Posted by Gungnir Erm no the inverse square law was alleged to have been stolen from Robert Hooke, Keplers third law involves a cubic law (the square of the orbital period is directly proportional to the cube of the semi-major axis of it's orbit) how it was "proved" was to equate the square of the rotational period of two bodies divided by the cube of their semi-major axes and see whether they did indeed roughly equal, and it was found that four of Jupiter's moons did indeed roughly agree with this law. Many arguments exist about where the inverse square law comes from but Robert Hooke claimed at the time published he was responsible for it in relation to Newtons Law of Gravity, and there wasn't much arguing against it (Hooke was a serious heavyweight with the Royal Society at the time and had corresponded with Newton).
Whether Hooke, Newton or Halley came up with the inverse square law, historically it was always derived from Kepler's third.
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 Originally Posted by Gungnir Meanwhile, the inverse square law relates to a force, not an acceleration, the acceleration is the physical response of an object to a resultant force and is also proportional to that objects instantaneous mass.
No the inverse square law relates to rate of change of acceleration with distance moved away or towards the centre of a gravity field.

a x d x d = constant for any acceleration due to gravity at any distance from the centre of gravity field within the gravity field.

Not F x d x d = constant.

If you can explain how the inverse square law relates to force go for it. You will find the inverse square law is empirical as per the manner described here.

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 Originally Posted by Gungnir No mass does not exist in two forms, I don't know where you get that idea from.
Inertial mass = one kind. Gravitational mass = another kind.

How would anyone think that mass is not expected to be existing in two states when Einstein's relativity is based upon a suspected equivalence between inertial mass and gravitational mass?

You probably need to study physics a bit.  81 posts, read 71,179 times Reputation: 100 Curves in Space

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 Originally Posted by manygeese An apple aint going to pull the earth.
There is a problem with Newton's formula and that concerns MASS. Both Newton and Kepler formulated the equation together but did not consider or know about ZERO MASS particles such as PHOTONS. The equation in its original form does not handle ZERO MASS.

But Einstein, in simplicity, envisaged time-space curvature as the cause of things falling to a centre point. If you blow up a balloon and place it on the table and place your finger in the middle of it and push down, you get a depression. If you then take a ball-bearing and place it next to the depression it rolls down into the dip. You have a time-space curvature example of gravity and a weighted object falling into dense gravity.

The initial sides are less steep than those closer to your finger point, resulting in an example gravitational lensing. But the interesting point is that even ZERO MASS objects such as photons are affected by the time-space curvature effect. Which is one reason why light bends in space being affected by different time-space curvatures along its path. In geometrical terms, the curvature of a circle is the reciprocal of its radius k = 1/R. But Einstein used Tensor Calculus to develop equations for the curvature of space-time.

If you have nothing better to do, try on book on Tensor Calculus. They do not make it easy!

NQ   19 posts, read 20,436 times Reputation: 86
there is no zero mass, no mass - no energy here is equation E=mc^2, if we stop photon and take it`s energy we`ll get particle with mass  manygeese Location: Riachella, Victoria, Australia 359 posts, read 563,594 times Reputation: 378
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 Originally Posted by NickyQuen But Einstein, in simplicity, envisaged time-space curvature as the cause of things falling to a centre point.
You have a problem here. Time is an effect, not a cause. Space likewise. Both Einstein's theories are idiotic. Best less said about them the better.  Location: Whittier 3,007 posts, read 5,204,434 times Reputation: 3041
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