Proof of the apple 'pulling' the earth?

[Vkothii]

During does not equal simultaneous.

During a collision, there are forces acting simultaneously, so it does equal simultaneous.

During equals a series of cause and effect actions and reactions.

So, when two cars, or other masses collide, it's a series of actions? I thought a collision was a single action.
What do you think "during" means? You know there is no "moment" of collision that can be recorded or otherwise seen, right?

JR has the problem of making action and reaction simultaneous and not cause and effect. That does not help him.

But isn't it you that has the problem with cause and effect?
You keep saying that one "precedes" the other. How do you "know" this is the case?
Can't a cause and an effect be simultaneous? I thought that's what Newton (and my Physics teacher) was talking about, did I get this wrong? There's a cause, then the effect comes "later on"?
Why is there a delay? Have you managed to determine the length of this cause-effect delay interval? Is it constant or does it depend on something else?

 

[James R]

plane:

It is being suggested to the learned that the explanation of the high tide on the opposite side of the earth is an equal and opposite reaction to the one induced on the other side by the moon.

Impossible, because forces in an action-reaction pair, according to Newton's third law, always act on different objects.

I have misplaced my copy of Principia but if you read Newton’s introduction to universal gravitation where he declares that we must allow that all bodies whatsoever are endowed with a principal of mutual gravitation, the only small mass he cites as ‘attracting’ a larger mass is the moon to the earth through the tides.

Now you just need to catch up on all the other things that have happened in physics in the past 330 years or so.

In Cavendish experiments, the large mass is not observed to move.

Well, it's fixed in place, after all...

Force travels through matter.

Rubbish. Force does not travel anywhere.

I repeat: you need to get yourself an introductory textbook on physics. Find out what a force actually is. Learn what Newton's laws say.

Apply a force to one side of anything. It is not instantaneously felt on the other side. E.G. (vivid) Pushing passengers on a train in Japan.

You're confused because here you're not talking about one force, or one point-like object. Rather, you're talking about many forces and many objects, all at once.

The reason a passenger on the far side of the train does not feel the push on the near side instantaneously is because the push on the near side creates a pressure wave that has to propagate through several other passengers, and that takes time.

You're mixing up the movement of a pressure wave with the idea of force. The two things are not the same. Force has no speed. Force does not move.

 

[D H]

The point of raising the issue is, according to Newton’s third law, directly opposite the above arrow the weight of the earth should be a construct of 9.799 m/s/s. Not 9.8 m/s/s. It is being suggested to the learned that the explanation of the high tide on the opposite side of the earth is an equal and opposite reaction to the one induced on the other side by the moon.

Plane,

Tidal effects are proportional to 1/r[sup]3[/sup], not 1/r[sup]2[/sup]. This is important to science ...

This could be important to science.

... but what you wrote is not important to science. What you wrote is a red herring.

Force travels through matter. Apply a force to one side of anything. It is not instantaneously felt on the other side.

One of the cornerstones that distinguishes science from mere naval gazing is that scientific theories must agree with observations. We have amassed an incredible amount of data regarding the motion of the bodies in the solar system. The observed data agree with the central axiom shared by Newton's law of gravity and general relativity: to wit, all masses attract all other masses.

There are some flaws in Newton's law of gravity. One of them is that Newton's formulation assumes gravity propagates at an infinite speed. You are assuming this flaw (mostly a minor flaw regarding bodies in our solar system) falsifies everything in Newton's formulation. General relativity addresses this flaw. General relativity also explains why the assumption of infinite propagation speed is a very, very good one. The assumption only fails when coupled with very high speeds and long observation times-- e.g., the orbit of Mercury.

I was a bit leery in bringing GR to fore because you do not have an adequate understanding of the basics (Newtonian gravity). Jumping into advanced physics when you haven't even mastered the basics is usually not a good thing to do. The reason I brought GR into play is because you have raised the issue of infinite propagation speed more than once. Note well: All masses, small or large, attract all other masses in general relativity.

 

[James R]

D H:

Realise that plane's issues are not primarily with gravity. That's one reason I have tried to avoid GR.

plane's issue is more fundamental: he doesn't understand Newton's laws of motion. He doesn't really know what a force is, and Newton's third law is a complete mystery to him.

 

[D H]

James,
I realize that. Plane has raised the issue of infinite propagation speed multiple times. I decided to address the issue up-front.

Plane,
The infinite propagation speed in Newtonian gravity is a minor issue in comparison to what is going on in this thread. Before you even start to come to grips with advanced physics you need to have a solid handle on the basics. Newton's third law is one of those basics, and so is Newton's law of gravitation.

 

[plane]

No has addressed the mathematical point made in post 100 about whether or not a lesser gravitation towards the earth is a gravitation towards the moon.


All replies that don't address that issue are off target.


Can address the staggering obfuscation if wanted but this is a pre Newton issue.

Newton assumed that a lesser gravitation towards the earth is a gravitation towards the moon.

Well, if it is rational, beyond me to see how.

Can anyone really explain why Newton mathematically saw a lesser gravitation towards the earth as a gravitation towards the moon.

If the big mass in Cavendish experiments are fixed, they are fixed. Get around to checking that out when time permits.

 

[Vkothii]

The "lesser" gravitation is a term in the same formula that describes the (same) mutual attraction between a two-body system (like a kind of coupled oscillator), it's never equal to zero. The oscillator is "free moving", sort of, except it's also coupled to the Sun.

But if you treat the Earth-Luna system as a term in the formula for the Solar coupling, that has a solution, a result, too.
The Sun isn't fixed, as such, but it's orbiting (coupled to) the galactic centre.

BTW that must mean tides are raised on the surface of the Sun by the Earth-Luna system. Very small tides, but still tidal.

 

[D H]

No has addressed the mathematical point made in post 100 about whether or not a lesser gravitation towards the earth is a gravitation towards the moon.

Yes, I did.

Tidal effects are proportional to 1/r[sup]3[/sup], not 1/r[sup]2[/sup].

So, what is the perceived difference in gravitation acceleration on someone standing on the Earth due to a full moon versus a new moon? The Earth, along with the person on the Earth is accelerating toward the Moon. The difference in the acceleration toward the Moon between the point on the Earth closes to the Moon and the center of the Earth is

$$
\Delta a(a_m-Re, a_m) =
GM_{moon}\left(\frac 1 {(a_m-R_e)^2} - \frac 1 {a_m^{\;2}}\right)
$$

Since $$a_m \gg R_e$$,

$$
\Delta a(a_m-Re, a_m) \approx
2\frac {GM_{moon}}{a_m^{\;3}}R_e
$$

Doubling this to get the difference between full moon and new moon,

$$
\Delta a(a_m-Re, a_m+R_e) \approx
4\frac {GM_{moon}}{a_m^{\;3}}R_e
$$

Or about 2.2 nanometers/second squared.

 

[plane]

During a collision, there are forces acting simultaneously, so it does equal simultaneous.



So, when two cars, or other masses collide, it's a series of actions? I thought a collision was a single action.

I am probably wrong. Newton’s third law should be worded “To every action there is an equal and opposite action” ,though.

Impossible, because forces in an action-reaction pair, according to Newton's third law, always act on different objects.

Well there is forces directly opposite on either side of the earth. One side of the centre of the earth is one object, the other the other object. Not sure what you are getting at.

Well, it's fixed in place, after all...

Not clear that it is. The large dumbell is mechanically moved towards the small dumbbell. The two dumbbells are on the same axis. Whatever, without the large mass "gravitating" towards the small mass, not proof of apple attracting the earth. And as, explained setting mg =k. M.m/d x d, is only setting Newton’s second law equal to its self.

Rubbish. Force does not travel anywhere.
You're confused because here you're not talking about one force, or one point-like object. Rather, you're talking about many forces and many objects, all at once.

The reason a passenger on the far side of the train does not feel the push on the near side instantaneously is because the push on the near side creates a pressure wave that has to propagate through several other passengers, and that takes time.

You're mixing up the movement of a pressure wave with the idea of force. The two things are not the same. Force has no speed. Force does not move.

Fair enough.

Plane,

Tidal effects are proportional to 1/r3, not 1/r2. This is important to science ...

Think the 1/r3 is used to get around the sun having a greater rate of acceleration at the earth than the moon at the earth using 1/r2.

.. but what you wrote is not important to science. What you wrote is a red herring.

Why? How do you know that a lesser weight upon the earth is a weight directed at the moon.

If it is simple a lesser weight directed towards the moon because of the interactions of earth and moon gravities in the space between the earth and the moon, it is a significant deduction, one that culminates is a more rational understanding of why there are like tides on opposite sides of the earth and much, much more. Gives a plausible insight into the rotation rates of the planets.

 

[Vkothii]

the interactions of earth and moon gravities in the space between

Try to think of the gravitational interaction as a coupling.

It's like a big spring that keeps the Earth and Moon connected, there's a mutual connection, not two separate connections. The spring has "settled" and doesn't "spring" much, but it does still extend and contract a bit. It's had a few billion years to relax into the present state.

P.S. The 1/r^3 relation is to do with spheres, not distance from the surface, like gravity which is 1/r^2. Have another look at the math.

 

[plane]

Try to think of the gravitational interaction as a coupling.

It's like a big spring that keeps the Earth and Moon connected, there's a mutual connection, not two separate connections. The spring has "settled" and doesn't "spring" much, but it does still extend and contract a bit. It's had a few billion years to relax into the present state.

Coupling does not make sense when directions of descent are opposed.

A big spring implies a physical connection. That yours to explain what is in your mind but I think you should be able to see that I do not see two connections.

The proof of the smaller mass falling towards the larger mass is yet to appear in this thread.

Fundamental question.

With respect of this thread, the conviction that a large mass does not fall towards a small mass has grown.

Also the likelihood that Newton's third law is not his own has increased.

Thanks for leading the horse to the water on that Vkothii. All my back of the head thinking on force was that it is spontaneous. However had always assumed it was cause and effect from the way the law is framed in school books. You are a good teacher. Made me really think about what I believed.

Cheers

 

[plane]

What do you mean "I move to both exerting the same force on each other"? What is this supposed to mean??

A mass always exerts a force on another mass. The force is constant if the mass is constant.
They individually "exert" a force which is proportional to their individual mass.

Every particle in the universe "exerts" a force that is directly proportional to the product of their masses ans inversely proportional to the square of the their separation.

The famed law states different to what you post, Frud11.

The formula F=GMm/r^2 gives the magnitude of the force on one object (either M or m), and not some kind of "shared" force that applies to both objects.

Look deeper. The formula says M and m apply equal forces to each other.

JR contradicts your line Frud.

It's a bit sad this. Anyone who argues in favour of Newton's law of gravity on pure logic uses their intelligence badly is probably the best way to put it.

Newton entered an illogical phase when he proposed that unlike masses exert equal force upon each other. It was a nonsense to come up with.

So sad. Newtonian physics hides the tides and the most probable explanation of why all the planets rotate at the rates they do amongst much else.

Good bye and good luck. Newton's law of gravity is wrong. Any evidence that you believe demonstrates an apple pulling the earth, be scientific and look for other explanation.

 

[Vkothii]

Every particle in the universe "exerts" a force that is directly proportional to the product of their masses ans inversely proportional to the square of the their separation.

You've done it again. You've gone from "particle", to "their masses"; you've gone from one thing to more than one thing without drawing a breath.
How do you do that?

My alter-ego said:
"A mass always exerts a force on another mass." - Note, here it's one mass, and another mass.

" The force is constant if the mass is constant." - This means: if the mass is not constant, the force will change.

"They individually "exert" a force [on each other] which is proportional to their individual mass." - actually the force is exerted [between] both, and it's proportional to the product/sum of the masses, or it's a ratio of the product.

Yep, that last bit as it stood, was misleading, because neither body "exerts" a force, the force exists because there are two bodies.

P.S. you may not have realised that overturning Newton's theories will require that you explain Einstein's theories in a different way? You will also need to overturn 300 years of scientific thinking?

Go for it (God loves a trier, dude).

 

[James R]

It's a bit sad this. Anyone who argues in favour of Newton's law of gravity on pure logic uses their intelligence badly is probably the best way to put it.

Newton entered an illogical phase when he proposed that unlike masses exert equal force upon each other. It was a nonsense to come up with.

Since it is tied up in the very way that he defined the term "force", it is perfectly logical. If you have an alternative system that defines force differently, perhaps now would be a good time to outline your vision for us.

So sad. Newtonian physics hides the tides and the most probable explanation of why all the planets rotate at the rates they do amongst much else.

And I suppose you have a better explanation?

*yawn*

 

[Norsefire]

There is no need for proof.

The apple does indeed pull on the Earth........except that pull is so insignificant it does not matter.

 

[plane]

Duffers.


The question is how can the earth exert as much force on the sun as what the sun exerts upon the earth.

That is what happens according to Newton's guess at gravity. If you haven't the brains to answer, don't worry, it doesn't make you a lesser person.


Goodbye and good luck.

They have different masses children.

(JR, you have a lead in to a far superior explanation within this thread. Look back a few posts, you oaf. A lesser gravitation towards the earth, etc )

 

[Steve100]

Duffers.


The question is how can the earth exert as much force on the sun as what the sun exerts upon the earth.

That is what happens according to Newton's guess at gravity. If you haven't the brains to answer, don't worry, it doesn't make you a lesser person.


Goodbye and good luck.

They have different masses children.

(JR, you have a lead in to a far superior explanation within this thread. Look back a few posts, you oaf. A lesser gravitation towards the earth, etc )

It does not matter that they have different masses, as the force takes into account both masses.

 

[Vkothii]

They have different masses children.

That's why there is a force seen between them.
Why they accelerate towards each other.

What would there be if there was just one mass? Then say you divide this mass in two parts and move them apart?
Do you have the brains to try answering either question?

 

[plane]

It does not matter that they have different masses, as the force takes into account both masses.

Is this a genuine response?

The question is how can F1 = F2 if the masses are different.

(Mass proportional to gravity is not consistent with F1 = F2.)

That's why there is a force seen between them.
Why they accelerate towards each other.

What would there be if there was just one mass? Then say you divide this mass in two parts and move them apart?
Do you have the brains to try answering either question?

Avoided replying to you last night. You work out why. I stated Newton's law of gravity as it stands. Your defence of Newton's law of gravity was an attack on what I stated.

Moderators of a genuine physics forum would have picked you up on it.

The question, this forum being genuine or otherwise, still is how can the earth exert as much force on the sun as what the sun does upon the earth.

To answer your questions. If there was just one mass, there would be just one mass.


If you split them, inverse square law vector analysis says the smaller one will fall towards the larger one.

Why those with an education can't answer how the earth exerts as much force on the sun as the sun does on the earth is, well, mildly intriguing. I know no-one can but it is still intriguing finding out that scholars become dumb when the question is posed.

 

[Steve100]

Check out binary stars. They are proof that the smaller mass can pull the larger mass.
If it wasn't so, the smaller star would orbit the larger one.
That however does not happen. And what does happen is they orbit the centre of mass of the pair.
They would only do this if the smaller star attracts the larger star.