The Flat Earth Society

Flat Earth Discussion Boards => Flat Earth General => Topic started by: E E K on February 11, 2018, 07:54:07 PM

Title: Are all masses like black holes?
Post by: E E K on February 11, 2018, 07:54:07 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0

How are two objects attracted to their center of mass with F=GMm/d^2 which is less than infinity?
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 07:59:25 PM
In a word, no.
Title: Re: Are all masses black holes?
Post by: Tessa Yuri on February 11, 2018, 07:59:52 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong
Title: Re: Are all masses black holes?
Post by: Curiouser and Curiouser on February 11, 2018, 08:02:10 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0

How are two objects attracted to their center of mass with F=GMm/d^2 which is less than infinity?
No.

If you choose R = 0, then you also have to choose the mass applicable for R = 0.

Which would be M = 0.

So, rather than g = INFINITY, g = 0/0 which is undefined.

Title: Re: Are all masses black holes?
Post by: Lonegranger on February 11, 2018, 08:04:16 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!
Title: Re: Are all masses black holes?
Post by: Tessa Yuri on February 11, 2018, 08:07:33 PM
In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate.
This is a possibility, but not necessarily true; it raises a number of problems such as all our known laws of physics being wrong, since they cease to operate at this point.

Also not seeing how this ties in at all with the OP.
Title: Re: Are all masses black holes?
Post by: Lonegranger on February 11, 2018, 08:10:24 PM
In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate.
This is a possibility, but not necessarily true; it raises a number of problems such as all our known laws of physics being wrong, since they cease to operate at this point.

Also not seeing how this ties in at all with the OP.

Citation please....just borrowing one of your lines
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 08:11:07 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!

Just because your primitive knowledge doesn't understand what happens doesn't mean it is unknowable. Terms like 'laws of physics break down' or your 'cease to operate' is just short hand for 'I have no fucking idea what I'm talking about' and 'Our understanding of physics is incomplete and wrong'
Title: Re: Are all masses black holes?
Post by: Lonegranger on February 11, 2018, 08:11:41 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!

Just because your primitive knowledge doesn't understand what happens doesn't mean it is unknowable. Terms like 'laws of physics break down' or your 'cease to operate' is just short hand for 'I have no fucking idea what I'm talking about' and 'Our understanding of physics is incomplete and wrong'

Ok smart ass spill your beans....
And as for not knowing what youre fucking talking about, your a real expert on that.
Title: Re: Are all masses black holes?
Post by: Tessa Yuri on February 11, 2018, 08:16:16 PM
This is a possibility, but not necessarily true; it raises a number of problems such as all our known laws of physics being wrong, since they cease to operate at this point.

Citation please....just borrowing one of your lines
You said it yourself...
In the centre of a black hole [...] the laws of physics as we know them cease to operate.

Well, I mean you didn't say it, but the website you ripped it from did.
(https://preview.ibb.co/jLgNrS/lone_try_to_shill_harder_please.png) (https://ibb.co/ewcvBS)

If you want to disprove physics, you really need to do more research than the first result on a Google search...
Title: Re: Are all masses black holes?
Post by: E E K on February 11, 2018, 08:16:38 PM
The "g" of an earth decreases above the surface of the earth while increases below its surface till it reach infinity. Try at a point which is 0.000000000000000000000000000000000000000000001 mm just above the center of the earth. Plug it in the formula. This is just an example.
Title: Re: Are all masses black holes?
Post by: Tessa Yuri on February 11, 2018, 08:17:46 PM
The "g" of an earth decreases above the surface of the earth while increases below its surface till it reach infinity. Try at a point which is 0.000000000000000000000000000000000000000000001 mm just above the center of the earth. Plug it in the formula. This is just an example.
It has been demonstrated to you precisely how and why the formula is wrong. That isn't a scientific formula, it's a poor corruption of one.
Title: Re: Are all masses black holes?
Post by: Lonegranger on February 11, 2018, 08:21:36 PM
This is a possibility, but not necessarily true; it raises a number of problems such as all our known laws of physics being wrong, since they cease to operate at this point.

Citation please....just borrowing one of your lines
You said it yourself...
In the centre of a black hole [...] the laws of physics as we know them cease to operate.

Well, I mean you didn't say it, but the website you ripped it from did.
(https://preview.ibb.co/jLgNrS/lone_try_to_shill_harder_please.png) (https://ibb.co/ewcvBS)

If you want to disprove physics, you really need to do more research than the first result on a Google search...

Why? When its common knowledge. Plus Ive got a sore finger, hence all my typos! Plus Im not trying to disprove physics, Im disagreeing with you.....very, ouch, different things!
Title: Re: Are all masses black holes?
Post by: markjo on February 11, 2018, 08:26:03 PM
Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/
Title: Re: Are all masses black holes?
Post by: Tessa Yuri on February 11, 2018, 08:26:24 PM
Why?
Why is it problematic to only use the first Google search result in an argument about an incredibly complex scientific topic? Gee, I'm not sure.

Maybe because this is the third result:
(https://image.ibb.co/g2FXrS/lone_come_on_this_is_basic_research.png) (https://imgbb.com/)
All you had to do was roll the scroll button on your mouse twice, something that isn't particularly difficult to do, even with a sore finger.
Title: Re: Are all masses black holes?
Post by: rabinoz on February 11, 2018, 08:28:01 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
No, it is not. The gravitation field at a point inside a sphere, at radius r from the centre, is due only to the mass inside radius r.

Quote from: E E K link
How are two objects attracted to their center of mass with F=GMm/d^2 which is less than infinity?
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 08:30:39 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!

Just because your primitive knowledge doesn't understand what happens doesn't mean it is unknowable. Terms like 'laws of physics break down' or your 'cease to operate' is just short hand for 'I have no fucking idea what I'm talking about' and 'Our understanding of physics is incomplete and wrong'

Ok smart ass spill your beans....

Firstly, I have tried to articulate the workings of the universe here prior, but either no one listens, cares or just parrots shit they think is correct and will take no other thinking seriously. Even if they are wrong and what they deny is the truth. Secondly, is it even wise to impart this knowledge to people that are far too young to deal with it? All I can do is guide you on a path. You must walk it.

What I will reveal is you need to think of black holes as not operating on a linear time dimension. If you wish to learn more about the nature of the universe you need to shake off the notion that time runs like a line, that has a beginning, middle and end. Time is a point (no not a spatial dimension style). Everything is, was and will be. The universe is both a planck hot singularity and an infinitely vast void of nothingness what you describe as its heat death as well as everything and every 'moment' in between all together. Your life experience and consciousness may seem linear, but for the universe it's not. What does this have to do with mass and black holes you ask? Well, what you perceive as the universe, IS the inside of a blackhole, or more apt, a singularity

You think you have free will, but do you? Everything post you make, has already been written  ;)
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 08:35:27 PM
Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/

At this point, outside forces come into play, like the sun, or the jiggling jugs of an alien babe on the far end of the Triangulum galaxy. There is no point in the universe where this 'gravity' is non existent. Everything that has mass is attracted to everything in the universe. It is measurable. No exceptions
Title: Re: Are all masses black holes?
Post by: Lonegranger on February 11, 2018, 08:36:24 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!

Just because your primitive knowledge doesn't understand what happens doesn't mean it is unknowable. Terms like 'laws of physics break down' or your 'cease to operate' is just short hand for 'I have no fucking idea what I'm talking about' and 'Our understanding of physics is incomplete and wrong'

Ok smart ass spill your beans....

Firstly, I have tried to articulate the workings of the universe here prior, but either no one listens, cares or just parrots shit they think is correct and will take no other thinking seriously. Even if they are wrong and what they deny is the truth. Secondly, is it even wise to impart this knowledge to people that are far too young to deal with it? All I can do is guide you on a path. You must walk it.

What I will reveal is you need to think of black holes as not operating on a linear time dimension. If you wish to learn more about the nature of the universe you need to shake off the notion that time runs like a line, that has a beginning, middle and end. Time is a point (no not a spatial dimension style). Everything is, was and will be. The universe is both a planck hot singularity and an infinitely vast void of nothingness what you describe as its heat death as well as everything and every 'moment' in between all together. Your life experience and consciousness may seem linear, but for the universe it's not. What does this have to do with mass and black holes you ask? Well, what you perceive as the universe, IS the inside of a blackhole, or more apt, a singularity

You think you have free will, but do you? Everything post you make, has already been written  ;)

So if thats the case you will have read this before...
Your totally full of shit, but slightly funny with it.
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 08:43:56 PM
Does gravity become infinity where the center of gravity of a mass lies?

Gravity pulls towards the center of mass. Simple Example;

Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
This equation doesn't work to calculate acceleration due to gravity, because you're using it in a case where nothing is being accelerated. There is no 'm' in your calculations, therefore there is no acceleration. You can see this because:
g = GM/R^2=nothing
There is no R, since there's no 'distance between' anything, or 'radius between' anything if you like, since there's only one object. Also, even if R=0, anything divided by 0 is nothing, not infinity.

So no, gravity is not infinite at the centre of mass, nor is gravity necessarily infinite at the centre of black holes. The Earth won't get sucked into itself, that doesn't make sense. For the Earth's mass to become a black hole, the Earth would have to be crushed to the size of a peanut. Then the density is so great it collapses in on itself to become a black hole.

tl;dr - your equation is wrong

In the centre of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become infinite and space-time curves infinitely, and where the laws of physics as we know them cease to operate....a bit like the inside of shifters head, but I thought you hated gravity!

Just because your primitive knowledge doesn't understand what happens doesn't mean it is unknowable. Terms like 'laws of physics break down' or your 'cease to operate' is just short hand for 'I have no fucking idea what I'm talking about' and 'Our understanding of physics is incomplete and wrong'

Ok smart ass spill your beans....

Firstly, I have tried to articulate the workings of the universe here prior, but either no one listens, cares or just parrots shit they think is correct and will take no other thinking seriously. Even if they are wrong and what they deny is the truth. Secondly, is it even wise to impart this knowledge to people that are far too young to deal with it? All I can do is guide you on a path. You must walk it.

What I will reveal is you need to think of black holes as not operating on a linear time dimension. If you wish to learn more about the nature of the universe you need to shake off the notion that time runs like a line, that has a beginning, middle and end. Time is a point (no not a spatial dimension style). Everything is, was and will be. The universe is both a planck hot singularity and an infinitely vast void of nothingness what you describe as its heat death as well as everything and every 'moment' in between all together. Your life experience and consciousness may seem linear, but for the universe it's not. What does this have to do with mass and black holes you ask? Well, what you perceive as the universe, IS the inside of a blackhole, or more apt, a singularity

You think you have free will, but do you? Everything post you make, has already been written  ;)

So if thats the case you will have read this before...
Your totally full of shit, but slightly funny with it.

Yes, your alt JackBlack said the same thing

Alt confirmed. I'll have to add you to my annihilation list. And you see with your dimwitted attitude why I wouldn't bother writing volumes of knowledge for you to simply dismiss anyway.

Title: Re: Are all masses like black holes?
Post by: E E K on February 11, 2018, 08:48:55 PM
Quote
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.

All the masses of the earth don't act separately when attracting things but act jointly at the center of the earth where the center of gravity of spherical earth is.

Are all masses like black holes? i corrected.
Title: Re: Are all masses like black holes?
Post by: markjo on February 11, 2018, 09:03:02 PM
Quote
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.

All the masses of the earth don't act separately when attracting things but act jointly at the center of the earth where the center of gravity of spherical earth is.
Only as far as objects external to the earth are concerned.  Inside the earth is a different story.
Quote from: https://en.wikipedia.org/wiki/Shell_theorem
Isaac Newton proved the shell theorem[1] and stated that:

    A spherically symmetric body affects external objects gravitationally as though all of its mass were concentrated at a point at its centre.
    If the body is a spherically symmetric shell (i.e., a hollow ball), no net gravitational force is exerted by the shell on any object inside, regardless of the object's location within the shell.

A corollary is that inside a solid sphere of constant density, the gravitational force varies linearly with distance from the centre, becoming zero by symmetry at the centre of mass.
Title: Re: Are all masses black holes?
Post by: Alpha2Omega on February 11, 2018, 09:08:56 PM
Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/

At this point, outside forces come into play, like the sun, or the jiggling jugs of an alien babe on the far end of the Triangulum galaxy. There is no point in the universe where this 'gravity' is non existent. Everything that has mass is attracted to everything in the universe. It is measurable. No exceptions

Yeah, he should have said "the gravity at the center of the earth due to the mass of the earth is zero because all of the mass around it pulls equally in all directions and cancels out."

Better?

BTW, gravity from masses in the Triangulum galaxy (whatever they are, titillating as your suggestion about what is important might be) is insignificant, and what is there is mostly balanced by gravity from similar (or otherwise) masses in galaxies in the opposite and all other directions, anyway, so it can be considered to be zero for most computations.
Title: Re: Are all masses black holes?
Post by: Shifter on February 11, 2018, 09:15:47 PM
Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/

At this point, outside forces come into play, like the sun, or the jiggling jugs of an alien babe on the far end of the Triangulum galaxy. There is no point in the universe where this 'gravity' is non existent. Everything that has mass is attracted to everything in the universe. It is measurable. No exceptions

Yeah, he should have said "the gravity at the center of the earth due to the mass of the earth is zero because all of the mass around it pulls equally in all directions and cancels out."

Better?

BTW, gravity from masses in the Triangulum galaxy (whatever they are, titillating as your suggestion about what is important might be) is insignificant, and what is there is mostly balanced by gravity from similar (or otherwise) masses in galaxies in the opposite and all other directions, anyway, so it can be considered to be zero for most computations.

I don't care if there is a Googolplex of zeros after a decimal point before a simple '1'. It is measurable at some point. Sure, our clumsy senses might not know the difference or feel ourselves being pushed and pulled from all directions but at some point, you can measure a number for anything that has mass in the universe. 
Title: Re: Are all masses like black holes?
Post by: E E K on February 11, 2018, 09:23:54 PM
Quote
Only as far as objects external to the earth are concerned.  Inside the earth is a different story.

The weight of a mass of 1 kg at the base of theoretical hole whose base is just 1m above the center of earth would be = w = mg = 1 (GM/(d)^2 = 3.8x10^14 N = I am just using mathematical equation w = mg
Title: Re: Are all masses like black holes?
Post by: markjo on February 11, 2018, 09:48:07 PM
Quote
Only as far as objects external to the earth are concerned.  Inside the earth is a different story.

The weight of a mass of 1 kg at the base of theoretical hole whose base is just 1m above the center of earth would be = w = mg = 1 (GM/(d)^2 = 3.8x10^14 N = I am just using mathematical equation w = mg
And I provided a reference showing why that doesn't apply inside a solid sphere.  Here it is again.  This time please make an effort to read it.
https://en.wikipedia.org/wiki/Shell_theorem
Title: Re: Are all masses like black holes?
Post by: E E K on February 11, 2018, 09:58:15 PM
Quote
And I provided a reference showing why that doesn't apply inside a solid sphere....
There is a difference between force on the particle and force between the particles. I mentioned this in one of my previous posts.

Gravity is always attractive, never cancel. As gravity pulls towards the center of mass, therefore, the power of gravity of all masses of earth concentrated at its center. If the gravity of earth is zero at its center then this means the value of gravitational constant "G" is zero at the center of gravity of all masses.
Title: Re: Are all masses like black holes?
Post by: Tessa Yuri on February 11, 2018, 09:59:44 PM
If the gravity of earth is zero at its center then this means the value of gravitational constant "G" is zero at the center of gravity of all masses.
That might be true if the formula you are using is scientific and accurate. But as has been demonstrated, it is not.
Title: Re: Are all masses like black holes?
Post by: Shifter on February 11, 2018, 10:00:21 PM
Consider the density. Just because something looks solid, doesn't mean there is no space in between it

Read up on neutron stars, quark stars, strange stars etc for what happens the more tightly you pack in mass
Title: Re: Are all masses black holes?
Post by: Curiouser and Curiouser on February 11, 2018, 11:06:00 PM
The "g" of an earth decreases above the surface of the earth while increases below its surface till it reach infinity. Try at a point which is 0.000000000000000000000000000000000000000000001 mm just above the center of the earth. Plug it in the formula. This is just an example.
Your example is many trillions times smaller than the Planck length.

Why would you expect your formula to work in that case?

Also, please provide the value of the mass in your formula.
Title: Re: Are all masses like black holes?
Post by: E E K on February 11, 2018, 11:13:38 PM
Quote
Your example is many trillions times smaller than the Planck length.
- i said that was just for your example. you can try this

The weight of a mass of 1 kg at the base of theoretical hole whose base is just 1m above the center of earth would be = w = mg = 1 (GM/(d)^2 = 3.8x10^14 N = I am just using mathematical equation w = mg
Title: Re: Are all masses like black holes?
Post by: Macarios on February 12, 2018, 12:15:40 AM
Quote
Your example is many trillions times smaller than the Planck length.
- i said that was just for your example. you can try this

The weight of a mass of 1 kg at the base of theoretical hole whose base is just 1m above the center of earth would be = w = mg = 1 (GM/(d)^2 = 3.8x10^14 N = I am just using mathematical equation w = mg

You are aware that deeper you go the Earth's gravity gets weaker, because only inner ball affects the object with own g.
Inner ball with radius up to the distance of the object to the center.
Closer to the center of the Earth you go, lower value of g you get.

Higher you go above the Earth's surface, lower the g gets.
Deper you go below the Earth's surface, lower the g gets.
At the center of the Earth g is zero.
Title: Re: Are all masses like black holes?
Post by: Curiouser and Curiouser on February 12, 2018, 01:05:38 AM
Quote
Your example is many trillions times smaller than the Planck length.
- i said that was just for your example. you can try this

The weight of a mass of 1 kg at the base of theoretical hole whose base is just 1m above the center of earth would be = w = mg = 1 (GM/(d)^2 = 3.8x10^14 N = I am just using mathematical equation w = mg
Details matter.

Your formula assumes that the entire mass of the earth is 1 meter away from your 1 kg mass.

Can you explain why you think this assumption is valid?

There are circumstances when it is valid for calculations to make the approximation that the entire mass of the earth resides at the center of the earth. There are other circumstances when it it not valid.

Your example falls into the second category.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 12, 2018, 02:33:43 AM
Quote
And I provided a reference showing why that doesn't apply inside a solid sphere....
There is a difference between force on the particle and force between the particles. I mentioned this in one of my previous posts.

Gravity is always attractive, never cancel. As gravity pulls towards the center of mass, therefore, the power of gravity of all masses of earth concentrated at its center. If the gravity of earth is zero at its center then this means the value of gravitational constant "G" is zero at the center of gravity of all masses.
Yes, but the force of gravitation is a vector and so the gravitational forces of all points outside the radius of your "test particle" cancel.

Why can't you believe what you are told by people who obviously know far more than you do? Read this again:
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/
Or read Wikipedia, Shell theorem (https://en.m.wikipedia.org/wiki/Shell_theorem)
Or Physics Forums, Gravity inside a solid sphere.  (https://www.physicsforums.com/threads/gravity-inside-a-solid-sphere.148579/)
Title: Re: Are all masses like black holes?
Post by: Curiouser and Curiouser on February 12, 2018, 08:42:15 AM
Much of FE relies on massive amounts of faked information and conspiracy to decieve. When you accept that level of disinfo, is it not possible to similarly accept that info from Wikipedia and Physics Forum is also intentionally incorrect?
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 11:13:00 AM
Quote
At the center of the Earth g is zero -
FINE i have no problem with that but it will make gravitational constant "G" zero at the center of earth as said before.
Quote
Your formula assumes that the entire mass of the earth is 1 meter away from your 1 kg mass.
First its not my formula. second the whole mass of earth concentrated at its center. Try at that place, plumb bob suspended from the top surface of the earth in a thought experiment.
Quote
regarding shell theorem -
i went through it many times but just keep in mind force of gravitatioon is BETWEEN two mass not ON masses - Newton says
Title: Re: Are all masses like black holes?
Post by: markjo on February 12, 2018, 11:38:09 AM
Quote
And I provided a reference showing why that doesn't apply inside a solid sphere....
There is a difference between force on the particle and force between the particles. I mentioned this in one of my previous posts.

Gravity is always attractive, never cancel. As gravity pulls towards the center of mass, therefore, the power of gravity of all masses of earth concentrated at its center. If the gravity of earth is zero at its center then this means the value of gravitational constant "G" is zero at the center of gravity of all masses.
So you believe Newton's general formula for gravity, but you don't believe the shell theorem that he proved to be correct for spherical objects?  Sorry, I can't help.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 11:48:21 AM
Quote
So you believe Newton's general formula for gravity, but you don't believe the shell theorem that he proved to be correct for spherical objects?  Sorry, I can't help.

There is a contradiction as said many times between "Newton's general formula for gravity" and "shell theorem" - I don't need your help in this regard but i consider it my duty to inform everyone. Choice is yours. I m not rude. ill correct myself if wrong
Title: Re: Are all masses like black holes?
Post by: Curiouser and Curiouser on February 12, 2018, 12:04:16 PM
Quote
Your formula assumes that the entire mass of the earth is 1 meter away from your 1 kg mass.
First its not my formula. second the whole mass of earth concentrated at its center. Try at that place, plumb bob suspended from the top surface of the earth in a thought experiment.
The whole mass of the Earth is not concentrated at its center in the formula you used. (Your formula. Knock off the pedantry.) Your thought experiment is flawed.
Title: Re: Are all masses black holes?
Post by: Alpha2Omega on February 12, 2018, 12:26:00 PM
Acceleration due to the gravity of earth on its surface; g = GM/R^2
Acceleration due to gravity of earth at its center; g = GM/R^2 = INFINITY, where R=0
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/

At this point, outside forces come into play, like the sun, or the jiggling jugs of an alien babe on the far end of the Triangulum galaxy. There is no point in the universe where this 'gravity' is non existent. Everything that has mass is attracted to everything in the universe. It is measurable. No exceptions

Yeah, he should have said "the gravity at the center of the earth due to the mass of the earth is zero because all of the mass around it pulls equally in all directions and cancels out."

Better?

BTW, gravity from masses in the Triangulum galaxy (whatever they are, titillating as your suggestion about what is important might be) is insignificant, and what is there is mostly balanced by gravity from similar (or otherwise) masses in galaxies in the opposite and all other directions, anyway, so it can be considered to be zero for most computations.

I don't care if there is a Googolplex of zeros after a decimal point before a simple '1'. It is measurable at some point. Sure, our clumsy senses might not know the difference or feel ourselves being pushed and pulled from all directions but at some point, you can measure a number for anything that has mass in the universe.

It's a good thing you don't care. We will most likely never be able to measure an effect of gravity that much smaller than, say, 1 g (g being the acceleration of gravity at the surface of the earth, roughly 10 m/s2), because the gravitational attraction of a single neutron at 1 km would swamp that by almost a googol orders of magnitude.

For the record, I calculate the acceleration due to gravity from the mass of one neutron 1 km away as approximately 10-43 m/s2, or g / 1044. Feel free to check that.

[Edit] typo.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 12:36:40 PM
Quote
The whole mass of the Earth is not concentrated at its center in the formula you used. (Your formula. Knock off the pedantry.) Your thought experiment is flawed.

come to the question - what is the gravity of earth at its own center - zero or infinity
Title: Re: Are all masses like black holes?
Post by: Alpha2Omega on February 12, 2018, 12:43:38 PM
Quote
The whole mass of the Earth is not concentrated at its center in the formula you used. (Your formula. Knock off the pedantry.) Your thought experiment is flawed.

come to the question - what is the gravity of earth at its own center - zero or infinity

Zero.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 12:47:28 PM
if g = 0 then  "G" also = 0
Title: Re: Are all masses like black holes?
Post by: blidge on February 12, 2018, 12:48:34 PM
Quote
The whole mass of the Earth is not concentrated at its center in the formula you used. (Your formula. Knock off the pedantry.) Your thought experiment is flawed.

come to the question - what is the gravity of earth at its own center - zero or infinity

Zero. If you stood there, the mass to your left would cancel the mass to your right. And so on.

Hypothetically if we could drill a hole through the Earth, traversing the centre, and dropped an object into the hole, then we would expect to see simple harmonic motion. The acceleration is at a maximum at the surface, and the velocity is equal to zero. At the centre, the velocity is at a maximum and the acceleration is zero.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 12:57:12 PM
Quote
the velocity is at a maximum and the acceleration is zero
- no "g" means no velocity as acceleration is the change in speed
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 01:22:58 PM
Quote
Zero. If you stood there, the mass to your left would cancel the mass to your right. And so on.

Hypothetically if we could drill a hole through the Earth, traversing the centre, and dropped an object into the hole, then we would expect to see simple harmonic motion. The acceleration is at a maximum at the surface, and the velocity is equal to zero. At the centre, the velocity is at a maximum and the acceleration is zero.

The mass of earth above the said object pulls it upward while the mass of the earth below the object pulls it downward at any point during its fall via the said hole. An object starts losing its acceleration "g" slowly till becomes zero at to center due bto equal pull in all direction on it.
Title: Re: Are all masses like black holes?
Post by: blidge on February 12, 2018, 01:25:18 PM
Quote
the velocity is at a maximum and the acceleration is zero
- no "g" means no velocity as acceleration is the change in speed

Not quite. Velocity is a vector and so has a magnitude and direction.

Quote
Zero. If you stood there, the mass to your left would cancel the mass to your right. And so on.

Hypothetically if we could drill a hole through the Earth, traversing the centre, and dropped an object into the hole, then we would expect to see simple harmonic motion. The acceleration is at a maximum at the surface, and the velocity is equal to zero. At the centre, the velocity is at a maximum and the acceleration is zero.

The mass of earth above the said object pulls it upward while the mass of the earth below the object pulls it downward at any point during its fall via the said hole. An object starts losing its acceleration "g" slowly till becomes zero at to center due bto equal pull in all direction on it.

Unless I'm massively misreading, I think you've got it.

Initially all of the mass of Earth is below the object. This value then decreases as the object moves closer towards the centre. At the centre, the object has an equal amount of mass around it in all directions. But it has gained kinetic energy as it has decreased its initial gravitational potential energy. This kinetic energy is enough to propel it through the centre and toward the opposite side. However now the amount of mass below is increasing until the Earth can be said to be once again below it and the cycle repeats.
Title: Re: Are all masses like black holes?
Post by: Macarios on February 12, 2018, 01:38:06 PM
Quote
At the center of the Earth g is zero -
FINE i have no problem with that but it will make gravitational constant "G" zero at the center of earth as said before.

Nope.
It would make internal part of the mass zero.
G would remain the same.
You mentioned the Shell thorem, but you fail to understand it.

Every force between two bodies is actally resutant of all forces between atoms of the two objects.
Resultant force is mathematical representation used in our calculations and we have to know when it is valid to use it.

Earth consists of atoms, and every atom is acting with own force, multitude of atoms act with complete set of forces.

To understand shell theorem, you will have to understand Earth (multitude of atoms) as set of layers.
At some depth you have layers that surround you and cancel their own gravitational forces.
At the same depth the remaining layers (that are deeper than you are) act with attraction force.

Inner set of layers have lower mass.
They attract you less because they have less mass remaining, not because G is changing.
Deeper you go, less of the mass of the Earth is left to attract you.
Outer layers stop pulling you when you enter them.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 02:11:35 PM
Quote
Nope.
It would make internal part of the mass zero.
- Great
The center of mass is the mean position of the mass in an object while the center of gravity is the point where gravity of the mass appears to act.. Here both points coincide. The gravity of the whole earth concentrated at its center, therefore, an earth attracts things towards its center. If "g" of the earth doesn't appear at its center then the earth would not attract things towards its center.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 03:56:16 PM
Quote
Every force between two bodies is actally resutant of all forces between atoms of the two objects.

I think Newton didn't discuss his law of gravity at atomic level however if you want then you can calculate the gravitational acceleration (g = GM/R^2) of proton or neutron at their centers; where M is the mass of proton or neutron and R is the radius of proton or neutron. At their centers, R=0 but not M. 
Title: Re: Are all masses like black holes?
Post by: Macarios on February 12, 2018, 05:39:44 PM
Quote
Every force between two bodies is actally resutant of all forces between atoms of the two objects.

I think Newton didn't discuss his law of gravity at atomic level however if you want then you can calculate the gravitational acceleration (g = GM/R^2) of proton or neutron at their centers; where M is the mass of proton or neutron and R is the radius of proton or neutron. At their centers, R=0 but not M.

I know what would you like things to be, but I can't help you with that.
Newton discussed his laws for gravitational fields outside of objects.
Title: Re: Are all masses like black holes?
Post by: Shifter on February 12, 2018, 05:47:33 PM
Quote
Every force between two bodies is actally resutant of all forces between atoms of the two objects.

I think Newton didn't discuss his law of gravity at atomic level however if you want then you can calculate the gravitational acceleration (g = GM/R^2) of proton or neutron at their centers; where M is the mass of proton or neutron and R is the radius of proton or neutron. At their centers, R=0 but not M.

I know what would you like things to be, but I can't help you with that.
Newton discussed his laws for gravitational fields outside of objects.

He was only half right. The heart of the field lies in a different dimension
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 07:00:24 PM
Quote
Newton discussed his laws for gravitational fields outside of objects.
- Any source

But Newton's universal law of gravitation states that any two masses attract each other with a force equal to a constant (constant of gravitation) multiplied by the product of the two masses and divided by the square of the distance between them - I don't see anything regarding gravitational fields outsides objects.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 12, 2018, 07:24:11 PM
Quote
Newton discussed his laws for gravitational fields outside of objects.
- Any source

But Newton's universal law of gravitation states that any two masses attract each other with a force equal to a constant (constant of gravitation) multiplied by the product of the two masses and divided by the square of the distance between them - I don't see anything regarding gravitational fields outsides objects.
Newton and all the objects he was using in his experiments were outside the earth.

So, I don't care what you see or don't see, the gravitational field inside a sphere at radius r is only due to the part of the sphere inside radius r.

Read again!
Why can't you believe what you are told by people who obviously know far more than you do? Read this again:
Actually, the gravity at the center of the earth is zero because all of the mass around it pulls equally in all directions and cancels out.
https://www.pbslearningmedia.org/resource/oer08.sci.phys.maf.gravitynsn/gravity-at-earths-center/
Or read Wikipedia, Shell theorem (https://en.m.wikipedia.org/wiki/Shell_theorem)
Or Physics Forums, Gravity inside a solid sphere. (https://www.physicsforums.com/threads/gravity-inside-a-solid-sphere.148579/)

Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 07:51:00 PM
how would you handle an object inside a half-spherical shell
Title: Re: Are all masses like black holes?
Post by: Alpha2Omega on February 12, 2018, 08:37:05 PM
how would you handle an object inside a half-spherical shell

It would be different. Why do you ask?
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 12, 2018, 08:39:45 PM
how would you handle an object inside a half-spherical shell
With great difficulty.
Title: Re: Are all masses like black holes?
Post by: E E K on February 12, 2018, 08:44:14 PM
Quote
It would be different. Why do you ask?

Please explain how would you apply universal law gravitation in an aforesaid situation (an object inside a half-spherical shell)? - I wanna know

Edit: Would the praxis of shell theorem be amenable to hemispherical shell or quasi-cross-section, disorderly holes in the shell and asymmetrical shell?
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 13, 2018, 12:27:32 AM
Quote
It would be different. Why do you ask?

Please explain how would you apply universal law gravitation in an aforesaid situation (an object inside a half-spherical shell)? - I wanna know
In the general case you need to sum all the individual forces between each small piece of one object with each small piece of the other  object.  The problem becomes a 3-D vector integration and a "bit above my pay-grade", which doesn't say much as my pay-grade is zero.

It is a little simpler if you just want the gravitational field at one point near a fairly regular object.
Often that object can be broken up into simpler parts, like rings etc, and these summed.

In general the only practical solution is to sum all individual contributions numerically, see:
Physics Stack Exchange, Gravitational Field from Irregular Object. (https://physics.stackexchange.com/questions/69514/gravitational-field-from-irregular-object)
And to show the complexity of the problem, there is: Physics Forums, Gravitational field strength for irregular object. (https://www.physicsforums.com/threads/gravitational-field-strength-for-irregular-object.629942)

Quote from: E E K
Edit: Would the praxis of shell theorem be amenable to hemispherical shell or quasi-cross-section, disorderly holes in the shell and asymmetrical shell?

I don't think so, but maybe someone more qualified than I can tell you more.

Title: Re: Are all masses like black holes?
Post by: Papa Legba on February 13, 2018, 12:34:01 AM
Quote
It would be different. Why do you ask?

Please explain how would you apply universal law gravitation in an aforesaid situation (an object inside a half-spherical shell)? - I wanna know
In the general case you need to sum all the individual forces between each small piece of one object with each small piece of the other  object.  The problem becomes a 3-D vector integration and a "bit above my pay-grade", which doesn't say much as my pay-grade is zero.

It is a little simpler if you just want the gravitational field at one point near a fairly regular object.
Often that object can be broken up into simpler parts, like rings etc, and these summed.

In general the only practical solution is to sum all individual contributions numerically, see:
Physics Stack Exchange, Gravitational Field from Irregular Object. (https://physics.stackexchange.com/questions/69514/gravitational-field-from-irregular-object)
And to show the complexity of the problem, there is: Physics Forums, Gravitational field strength for irregular object. (https://www.physicsforums.com/threads/gravitational-field-strength-for-irregular-object.629942)

Quote from: E E K
Edit: Would the praxis of shell theorem be amenable to hemispherical shell or quasi-cross-section, disorderly holes in the shell and asymmetrical shell?

I don't think so, but maybe someone more qualified than I can tell you more.

Someone who doesn't think satellites sit on tables maybe?

https://www.theflatearthsociety.org/forum/index.php?topic=73925.msg2024607#msg2024607
Title: Re: Are all masses like black holes?
Post by: blidge on February 13, 2018, 03:36:07 AM
Quote
It would be different. Why do you ask?

Please explain how would you apply universal law gravitation in an aforesaid situation (an object inside a half-spherical shell)? - I wanna know
In the general case you need to sum all the individual forces between each small piece of one object with each small piece of the other  object.  The problem becomes a 3-D vector integration and a "bit above my pay-grade", which doesn't say much as my pay-grade is zero.

It is a little simpler if you just want the gravitational field at one point near a fairly regular object.
Often that object can be broken up into simpler parts, like rings etc, and these summed.

In general the only practical solution is to sum all individual contributions numerically, see:
Physics Stack Exchange, Gravitational Field from Irregular Object. (https://physics.stackexchange.com/questions/69514/gravitational-field-from-irregular-object)
And to show the complexity of the problem, there is: Physics Forums, Gravitational field strength for irregular object. (https://www.physicsforums.com/threads/gravitational-field-strength-for-irregular-object.629942)

Quote from: E E K
Edit: Would the praxis of shell theorem be amenable to hemispherical shell or quasi-cross-section, disorderly holes in the shell and asymmetrical shell?

I don't think so, but maybe someone more qualified than I can tell you more.

Someone who doesn't think satellites sit on tables maybe?

https://www.theflatearthsociety.org/forum/index.php?topic=73925.msg2024607#msg2024607

Said the guy who couldn't understand what the m stands for in F=ma
Title: Re: Are all masses like black holes?
Post by: Macarios on February 13, 2018, 04:11:50 AM
Quote
Newton discussed his laws for gravitational fields outside of objects.
- Any source

But Newton's universal law of gravitation states that any two masses attract each other with a force equal to a constant (constant of gravitation) multiplied by the product of the two masses and divided by the square of the distance between them - I don't see anything regarding gravitational fields outsides objects.

Ok, apply your own claim on explanation WHY homogenous infinite plane doesn't change attraction on object with object's distance from the plane.

Also, WHY is gravity force inside shell zero?
Show yourself HOW is that explained.
Title: Re: Are all masses like black holes?
Post by: E E K on February 13, 2018, 04:05:51 PM
Quote
I don't think so, but maybe someone more qualified than I can tell you more.
- You seem to be an honest guy
Quote
Ok, apply your own claim on explanation WHY homogenous infinite plane doesn't change attraction on object with object's distance from the plane.
- I dont have any personal claim. I just follow the laws of physics. Can you rephrase your question I didn't understand
Quote
Also, WHY is gravity force inside shell zero?
- I never said gravity force inside shell is zero Again G = 0, when gravity force or g = 0

Let an object located inside the spherical shell. The acceleration due to gravity g of an object is much greater (say 1000 times) than the g of a spherical shell. The radius of the object is much smaller than the radius of shprical shell. An object may be solid sphere, semi-solid spherical shell etc - What would you think about the aforesaid?

Also, how one can determine the acceleration due to gravity g =GM/R^2 of a spherical shell, hemispherical shell, disorderly holes in the shell and asymmetrical shell etc  - Let the mass of each = 1 kg. and Radius = 1 meter - Just wondering
Title: Re: Are all masses like black holes?
Post by: markjo on February 13, 2018, 07:18:25 PM
*sigh*
Title: Re: Are all masses like black holes?
Post by: E E K on February 13, 2018, 08:53:47 PM
Quote
Drive an equation for the acceleration due to gravity at any depth within the earths surface
Is it derived by Newton?

I think you missed one of my posts. Anyhow, place an object at any depth within the earths surface

There is a mass of earth Ma above the object in horizontal plane

There is a mass of earth Mb below the object in horizontal plane

Ma pulls the object upward with g1  while
Mb pulls the object downward with g2

An object starts losing "g2" while gaining g1 as it goes down till g1 = g2 or both g1 and g2 turn into full ge at the center of earth.

I know you wouldnt agree with this but IMPOV this is true as the effect of g1 is missing in derivation.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 13, 2018, 11:26:59 PM
Also, how one can determine the acceleration due to gravity g =GM/R^2 of a spherical shell,
The spherical shell is easy. Inside g = 0 and outside g =GM/R^2.


Quote from: E E K
hemispherical shell, disorderly holes in the shell and asymmetrical shell etc  - Let the mass of each = 1 kg. and Radius = 1 meter - Just wondering
Not at all easy, each has to be down by a complicated integration process. Often this is done numerically.

But any mass of only 1 kg has infinitesimal gravitation.
On the surface of a sphere of the size you give it would be about 2.67 x 1010 N/kg (or m/s2).
Title: Re: Are all masses like black holes?
Post by: Macarios on February 13, 2018, 11:29:07 PM
Quote
Ok, apply your own claim on explanation WHY homogenous infinite plane doesn't change attraction on object with object's distance from the plane.
- I dont have any personal claim. I just follow the laws of physics. Can you rephrase your question I didn't understand

If you follow the laws of physics then you will understand this:
Put small object in the center of big ball (or cube).
Left half of the ball will pull the small object to the left, right half will pull the object to the right.
Halves have same masses and inflict equal forces, each in own direction.
Forces of those halves will act on the same object, in opposite directions, and cancel each other.

Quote
Also, WHY is gravity force inside shell zero?
- I never said gravity force inside shell is zero Again G = 0, when gravity force or g = 0

Let an object located inside the spherical shell. The acceleration due to gravity g of an object is much greater (say 1000 times) than the g of a spherical shell. The radius of the object is much smaller than the radius of spherical shell. An object may be solid sphere, semi-solid spherical shell etc - What would you think about the aforesaid?

Also, how one can determine the acceleration due to gravity g =GM/R^2 of a spherical shell, hemispherical shell, disorderly holes in the shell and asymmetrical shell etc  - Let the mass of each = 1 kg. and Radius = 1 meter - Just wondering

You didn't say it, but physics did, and you say you follow laws of physics.
Inside homogenous hollow sphere acceleration g and gravitational force F is zero.

All sides of the hollow sphere pull in every direction and resultant is zero.
Imperfections or deformations of sphere will change balance and resultant will pull toward places with higher thickness or density.
Thinner or less dense parts will reduce that pull, but not completely.

The acceleration g (1000 times greater) you mention will work outside of the sphere, and be smaller and smaller as you go away from it.

Now, about that infinite plane.
It will pull small object towards it.
It will pull two objects towards two different spots, directly below each of them.
But unlike spheres, infinite plane gives constant g at all altitudes.
So, where is the center of mass of infinite plane?
How can you apply "F = GMm/d2" ?
Which d will you use?

As you can see, you don't use resultant as you would when objects are t some distance from each other.
You will use integral function that sums vectors of gravitational forces of individual parts of the plane.
Smaller the parts you choose, more of them you have, more accurate you calculate.

Laws of physics are tools.
Our mathematical explanations of nature, and ways to predict behavior, or to plan actions in order to get desired result.
As every other tool, you have to know how and where you can use it.
It is hard to tighten 12 mm nut with 9 mm wrench.
Title: Re: Are all masses like black holes?
Post by: markjo on February 14, 2018, 06:55:26 AM
Quote
Drive an equation for the acceleration due to gravity at any depth within the earths surface
Is it derived by Newton?
Yes.
https://www.math.ksu.edu/~dbski/writings/shell.pdf
Title: Re: Are all masses like black holes?
Post by: E E K on February 14, 2018, 07:02:19 PM
Quote
You didn't say it, but physics did, and you say you follow laws of physics.
Inside homogenous hollow sphere acceleration g and gravitational force F is zero.
Let's try again

Imagine a small solid sphere A located inside a very large hollow sphere B but their centers dont coincide. The gravitational acceleration g of A is much greater than g of B.

There are two possibilities

   Gravitational Force between two masses: Center of both A and B coincide due to universal law of gravitation

   Gravitational Force on mass: Part of B located near A fall on the solid sphere due to less distance and greater accelerations due to gravities. The greater is the distance them the smaller is the g

The force of the Earth on the apple is exactly equal and opposite to the force of the apple on the Earth but what makes the difference are accelerations due to gravities

You seem to sum all the individual forces and make the resultant zero but ignore their accelerations due to gravities.

I asked a question about gravity at the center of earth but you said: it would make internal part of the mass zero by limiting the value of R to zero in g=GM/R^2.

Gravity at the center of earth with a radius of R is not equal to zero. This is the center of gravity of earth or this is the center where gravity of whole mass of earth appears to act.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 14, 2018, 09:21:02 PM
Quote
You didn't say it, but physics did, and you say you follow laws of physics.
Inside homogenous hollow sphere acceleration g and gravitational force F is zero.
Let's try again

Imagine a small solid sphere A located inside a very large hollow sphere B but their centers dont coincide. The gravitational acceleration g of A is much greater than g of B.
I think that a lot of your confusion is trying to assign g's to every object. In my opinion the idea of assigning a gravitational acceleration to an object is useful only for massive  objects like the earth or the moon.

Quote from: E E K
There are two possibilities

   Gravitational Force between two masses: Center of both A and B coincide due to universal law of gravitation

   Gravitational Force on mass: Part of B located near A fall on the solid sphere due to less distance and greater accelerations due to gravities. The greater is the distance them the smaller is the g
There is no gravitational field inside the  "very large hollow sphere B" due to B. So there is no force on A or B.

Quote from: E E K
The force of the Earth on the apple is exactly equal and opposite to the force of the apple on the Earth but what makes the difference are accelerations due to gravities
No, the accelerations are due to the forces. One way to calculate "g" is to calculate the gravitational force on a test mass of 1 Kg.
In fact, while "g" is usually written in units of acceleration, m/s2, but equivalent and often better units are force per unit mass or N/kg.

Quote from: E E K
You seem to sum all the individual forces and make the resultant zero but ignore their accelerations due to gravities.
There are no separate "accelerations due to gravities". The acceleration of each object is simply dye to the one force acting on each object.

Quote from: E E K
I asked a question about gravity at the center of earth but you said: it would make internal part of the mass zero by limiting the value of R to zero in g=GM/R^2.
As I and others have said, there is no gravitational field inside a spherical shell, due to that shell. This is true for any thickness shell.
So at the centre of the earth, at a radius of zero, there can be no mass inside.

Quote from: E E K
Gravity at the center of earth with a radius of R is not equal to zero. This is the center of gravity of earth or this is the center where gravity of whole mass of earth appears to act.
No, I'm afraid that "Gravity at the center of earth with a radius of R is" equal to zero.

The whole mass of a sphere appears to act at the centre, only for points outside the sphere.

For points inside the sphere, at radius r from the centre, the gravitational force is only that due to the mass inside radius r .
And that is what everybody else here and all the freeness say.
Title: Re: Are all masses like black holes?
Post by: Macarios on February 15, 2018, 01:35:14 AM
Quote
You didn't say it, but physics did, and you say you follow laws of physics.
Inside homogenous hollow sphere acceleration g and gravitational force F is zero.
Let's try again

Imagine a small solid sphere A located inside a very large hollow sphere B but their centers dont coincide. The gravitational acceleration g of A is much greater than g of B.

There are two possibilities

   Gravitational Force between two masses: Center of both A and B coincide due to universal law of gravitation

   Gravitational Force on mass: Part of B located near A fall on the solid sphere due to less distance and greater accelerations due to gravities. The greater is the distance them the smaller is the g

The force of the Earth on the apple is exactly equal and opposite to the force of the apple on the Earth but what makes the difference are accelerations due to gravities

You seem to sum all the individual forces and make the resultant zero but ignore their accelerations due to gravities.

I asked a question about gravity at the center of earth but you said: it would make internal part of the mass zero by limiting the value of R to zero in g=GM/R^2.

Gravity at the center of earth with a radius of R is not equal to zero. This is the center of gravity of earth or this is the center where gravity of whole mass of earth appears to act.

Inside solid hollow homogenous sphere resultant g is zero, not because G is zero.
G is always 6.67408 x 10 -11, hence the name Gravitational CONSTANT. It is mathematical factor used in formulas. Our own tools.
Reason why g = 0 inside is because opposite sides of hollow sphere cancel each other's influence on the particle inside.
One pull one way, other pull the opposite.

Derived formula you are trying to use came from integral function of individual pull from parts of body.
It is just a resultant and you have to know where and when you can use it with satisfactory accuracy.
It works outside the sphere.

When the object is inside, one side of sphere is pullin in one direction and other side is pulling in other direction.
Newton gave proof of that.
Go to THIS ARTICLE (https://en.wikipedia.org/wiki/Shell_theorem), and scroll down to "Newton's Proofs".
There's a part named "Force on a Point Inside a Hollow Sphere".

Look at Fig. 2
Particle inside the sphere is pulled by mass distributed in sphere walls, not by empty spot S in the middle of the sphere.
Outside, the whole pull acts toward one side. Resultant would be toward S and we can use F = GMm / d2.
Inside the pull is toward everywhere. All around. The formula doesn't work here.

If particle P is closer to one side of wall it is by another side pulled weaker because of distance, but harder because from same angle is pulled by more mass.
There's more mass from K to L than from I to H.
Those two factors perfectly balance one another and resultant is equal to pull from closer part of the sphere with less mass.
Pull towards J is equal and opposite to pull towards M, and in all other directions situation is similar.
And all of that acts on the same particle P.
Total pull is zero.

(https://upload.wikimedia.org/wikipedia/commons/2/29/Attraction_Interior_Sphere.png)


------------------------------------------

Quote
The force of the Earth on the apple is exactly equal and opposite to the force of the apple on the Earth but what makes the difference are accelerations due to gravities

Already told you:
Force by the Earth on apple is pulling apple, not Earth.
Force by the apple on Earth is puling Earth, not apple in that opposite direction.
Earth is pulling one object, apple is pulling another object.
Forces on two different objects don't cancel each other.

It only means that one object pulling another will not remain indifferent by pull by that other object back.
Similar thing you also have in magnetic fields.
One magnet pulling another will not stay in place.
They will both "jump" to each other.
Only, heavier magnet will jump less.

That is why, if you pull me with some rope, you have to support yourself with your leg to stay where you are.
If you don't, you'll also get pulled to central point between us.
Title: Re: Are all masses like black holes?
Post by: E E K on February 15, 2018, 06:47:50 PM
Quote
Inside solid hollow homogenous sphere resultant g is zero, not because G is zero.


Case #1: Resultant "g" is zero at the center of solid hollow homogenous sphere (HS) when there is no mass M at all inside HS

Case #2: Presence of M inside HS, however, M can be more in numbers too

There are two gravitational fields inside HS

1-   Due to  HS
2-   Due to M

Now there are three conditions

The g of HS < M, The g of HS = M, The g of HS > M

Also, the size, mass, and shape of M can be varied and its posture & location inside HS as well

All above is self-explanatory however I can explain in there is any question

Quote
Total pull is zero.
Most physicists agreed that gravities do not cancel each other even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero.

Mass closer to one side of the wall of HS: it depends upon the g of M and "g" of the mass of HS closer to the M. We know g increases with a decrease in distance.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 15, 2018, 07:41:20 PM
Quote
Inside solid hollow homogenous sphere resultant g is zero, not because G is zero.


Case #1: Resultant "g" is zero at the center of solid hollow homogenous sphere (HS) when there is no mass M at all inside HS

Case #2: Presence of M inside HS, however, M can be more in numbers too

There are two gravitational fields inside HS

1-   Due to  HS
2-   Due to M
No, as has been presented numerous times and with proof.
"Inside solid hollow homogenous sphere resultant g" due to the HS is zero everywhere.

Quote from: E E K
Now there are three conditions

The g of HS < M, The g of HS = M, The g of HS > M
Since the g of HS inside the HS is everywhere zero, obviously the only case is g of HS < M.

Quote from: E E K
Also, the size, mass, and shape of M can be varied and its posture & location inside HS as well

All above is self-explanatory however I can explain in there is any question
There is no question at all the total pull is zero.

Quote from: E E K
Quote
Total pull is zero.
Most physicists agreed that gravities do not cancel each other even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero.

Mass closer to one side of the wall of HS: it depends upon the g of M and "g" of the mass of HS closer to the M. We know g increases with a decrease in distance.
Where did you drag this up from, "Most physicists agreed that gravities do not cancel each other even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero."
No physicist would have made a statement like that.

Gravitation has both magnitude and direction (a vector) so, what you call "gravities" most certainly can cancel.
That is how there is no gravity inside a hollow sphere, due to that sphere.
Title: Re: Are all masses like black holes?
Post by: Macarios on February 15, 2018, 10:37:48 PM
Quote
Inside solid hollow homogenous sphere resultant g is zero, not because G is zero.


Case #1: Resultant "g" is zero at the center of solid hollow homogenous sphere (HS) when there is no mass M at all inside HS

Case #2: Presence of M inside HS, however, M can be more in numbers too

There are two gravitational fields inside HS

1-   Due to  HS
2-   Due to M

Now there are three conditions

The g of HS < M, The g of HS = M, The g of HS > M

Also, the size, mass, and shape of M can be varied and its posture & location inside HS as well

All above is self-explanatory however I can explain in there is any question

Quote
Total pull is zero.
Most physicists agreed that gravities do not cancel each other even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero.

Mass closer to one side of the wall of HS: it depends upon the g of M and "g" of the mass of HS closer to the M. We know g increases with a decrease in distance.

Mass on one side is closer, but there is more mass on another side.

If you don't understand English, try to pretend that you understand Hindi.
It might seem strange, but I'm sure you will understand this guy very well.

I'm not joking.
I don't speak Hindi, but I see what is he talking about.
Give it a try:

Title: Re: Are all masses like black holes?
Post by: E E K on February 16, 2018, 11:20:16 PM
Case #1: Resultant "g" is zero at the center of solid hollow homogenous sphere (HS) in the absence of mass both inside and outside

The whole mass of HS is concentrated at its center as mentioned many times earlier but if we examine the pull of individual particle of HS then the total pull between any two particles located opposite to each other on the inner wall of HS is zero and hence the resultant g zero at the center of particle only IMPOV

Quote
Mass on one side is closer, but there is more mass on another side.
There are three masses and three centers of gravities cg
Closer mass is gravitating mass if g of HS > g of particle
More mass is gravitating mass if g of HS > g of particle
Particle Falling mass

So total pull may be zero if

The value of g of closer mass at a height h from its cg to center of particle =  The value of g of more mass at a height h1 from its cg to center of particle

But the value of g of particle at height h or at the cg of closer mass is greater than the value of g of particle at height h1 or at the cg of more mass

No need to explain the following as its quite easy to understand

Case #2: Presence of M inside HS, however, M can be more in numbers too
There are two gravitational fields inside HS
1-   Due to  HS
2-   Due to M
Now there are three conditions
The g of HS < M, The g of HS = M, The g of HS > M
Also, the size, mass, and shape of M can be varied and its posture & location inside HS as well

Most physicists agreed that gravities do not cancel each other even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero.
Mass closer to one side of the wall of HS: it depends upon the g of M and "g" of the mass of HS closer to the M. We know g increases with a decrease in distance.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 17, 2018, 02:17:20 AM
Case #1: Resultant "g" is zero at the center of solid hollow homogenous sphere (HS) in the absence of mass both inside and outside
It's no point you saying the same ting over and over again. Whether you accept it or not,
"Resultant g is zero" everywhere inside a "hollow homogenous sphere (HS) in the absence of mass both inside and outside".

There are numerous references to this well know property of a spherical shell, here is one:
Quote
Gravity Inside a Spherical Shell
(http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/imgmech/sphshellin.gif)
For application of the law of gravity inside a uniform spherical shell of mass M, a point is chosen on the axis of a circular strip of mass. The problem is envisioned as dividing an infinitesemally thin spherical shell of density σ per unit area into circular strips of infinitesemal width. The choice of such a point involves no loss of generality because for any point inside the shell, the mass elements could be chosen so that the point is on their symmetry axis.
<< I'll let you look up the calculations if you feel qualified. >>
From: Gravity Force Inside a Spherical Shell (http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/sphshell2.html)
You could also look at: Wikipedia, Shell theorem (https://en.m.wikipedia.org/wiki/Shell_theorem) or Quora.com Why is gravity inside a spherical shell considered to be zero? (https://www.quora.com/Why-is-gravity-inside-a-spherical-shell-considered-to-be-zero)

Quote from: E E K
Most physicists agreed that gravities do not cancel each other
No! That is completely untrue. Gravitation has direction and so the gravitation from two object's can cancel.

Quote from: E E K
even if it does then again you are making g zero at the center of particle P inside the HS and hence G = 0 at the center of particles. Similarly, the weight of the imaginary earth on our real earth is also = 0; Two equal and opposite pulls so total pull is zero.
Mass closer to one side of the wall of HS: it depends upon the g of M and "g" of the mass of HS closer to the M. We know g increases with a decrease in distance.
The bit you are ignoring is that the closer part is smaller in area than the farther part by exactly the correct ratio for their gravitational forces to be equal and opposite.

Look, go and read the references that hopefully explain it better than I.
Title: Re: Are all masses like black holes?
Post by: Macarios on February 17, 2018, 04:29:59 AM
Your link to Quora points to pretty clear image of distribution of forces:

(https://qph.ec.quoracdn.net/main-qimg-d7001dd9dfefa24681878ac25011bcbb)
Title: Re: Are all masses like black holes?
Post by: E E K on February 17, 2018, 10:30:54 PM
Quote
Your link to Quora points to pretty clear image of distribution of forces:
- This is one way where is particle pull?

Following is the edit that I had done in the previous post. here it is if missed

Particle mass is Gravitating mass
Closer mass of HS is Falling mass
More mass of HS is Falling mass

But the value of g of particle at height h or at the cg of closer mass is greater than the value of g of particle at height h1 or at the cg of more mass
Title: Re: Are all masses like black holes?
Post by: Macarios on February 18, 2018, 02:45:41 AM
Quote
Your link to Quora points to pretty clear image of distribution of forces:
- This is one way where is particle pull?

Following is the edit that I had done in the previous post. here it is if missed

Particle mass is Gravitating mass
Closer mass of HS is Falling mass
More mass of HS is Falling mass

But the value of g of particle at height h or at the cg of closer mass is greater than the value of g of particle at height h1 or at the cg of more mass

That makes you closer to understanding why resultant "g" is zero inside homogenous hollow sphere.
Center of mass of one side is closer to inner particle, but mass of that side is smaller.
Center of mass of other side is farther from inner particle, but mass of that part is bigger.
Pull between the particle and one side in one direction becomes equal to pull between the particle and other side in opposite direction.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 18, 2018, 02:54:46 AM
Quote
Your link to Quora points to pretty clear image of distribution of forces:
- This is one way where is particle pull?

Following is the edit that I had done in the previous post. here it is if missed

Particle mass is Gravitating mass
Closer mass of HS is Falling mass
More mass of HS is Falling mass

But the value of g of particle at height h or at the cg of closer mass is greater than the value of g of particle at height h1 or at the cg of more mass
Here is another attempt at explaining that there is no "gravity" inside a spherical shel, due to thst shell:
Quote from: Physics Stack Exchange
Gravitational field intensity inside a hollow sphere
It is quite easy to derive the gravitational field intensity at a point within a hollow sphere. However, the result is quite surprising. The field intensity at any point within a hollow sphere is zero.

Answer from Hypnosifl
One intuitive way I've seen to think about the math is that if you are at any position inside the hollow spherical shell, you can imagine two cones whose tips are at your position, and which both lie along the same axis, widening in opposite direction. Imagine, too, that they both subtend the same solid angle, but the solid angle is chosen to be infinitesimal. Then you can consider the little chunks of matter where each cone intersects the shell, as in the diagram on this page:
(https://i.stack.imgur.com/CHcrm.gif)
One intuitive way I've seen to think about the math is that if you are at any position inside the hollow spherical shell, you can imagine two cones whose tips are at your position, and which both lie along the same axis, widening in opposite direction. Imagine, too, that they both subtend the same solid angle, but the solid angle is chosen to be infinitesimal. Then you can consider the little chunks of matter where each cone intersects the shell, as in the diagram on this page:

You still need to do a bit of geometric math, but you can show that the area of each red bit is proportional to the square of the distance from you (the blue point) to it--and hence the mass of each bit is also proportional to the square of the distance, since we assume the shell has uniform density. But gravity obeys an inverse-square law, so each of those two bits should exert the same gravitational pull on you, but in opposite directions, meaning the two bits exert zero net force on you. And you can vary the axis along which the two cones are drawn so that every point on the surface of the shell ends up being part of a pair like this, which leads to the conclusion that the entire spherical shell exerts zero net force on you.

Physics Stack Exchange, Gravitational field intensity inside a hollow sphere (https://physics.stackexchange.com/questions/150238/gravitational-field-intensity-inside-a-hollow-sphere)

But,  if you can't,  or won't do the maths yourself and won't believe the references from those that can, I don't know how to explain it any further.
Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 11:58:47 AM
Hope you may convince in my last try

NEWTON LAW OF GRAVITATION: The gravitational force BETWEEN two masses = F GMm/d^2

SPLIT ANALYSIS of Earth and Apple:

When an Earth is a gravitating mass and an Apple is a falling mass
Acceleration due to gravity of earth; ge = GM/R^2 (on the the surface of earth); where R = radius of earth.
So an apple fall on earth at the rate of ge

When an Apple is a gravitating mass and an Earth is a falling mass
Acceleration due to gravity of apple; ga = Gm/r^2 (on the surface of apple); where r = radius of apple
So an earth falls on an apple at the rate of ga

Force of Earth on Apple = Force of Apple on Earth
An apple falls due to ge on Earth. The earth also moves upwards towards apple due to ga of apple but by such a minuscule amount to be noticed or measured.

Shell Theorem

The presence of any mass M inside homogeneous Hallow Sphere HS. Two gravitational accelerations g are involved in this problem

1-   Acceleration due to gravity g of HS
2-   Acceleration due to gravity g of M

Three possible conditions

The g of HS < M, The g of HS = M, The g of HS > M

Also, the size, mass, and shape of M can be varied and its location inside HS as well

According to shell theorem: The entire spherical shell exerts zero net force on M

This may be true as I said earlier but this is not the end of story. There is mammoth difference between

Gravitational Force ON a mass and Gravitational Force BETWEEN two masses

Newtons gravitational force is between two masses. Gravitational force on a mass is only considered during split analyses like Earth on apple and Apple on earth. Their combined effect appears in F = GMm/d^2. As gravitational force is a force that attracts any objects with mass therefore HS attracts M but M also attracts HS.

The miscalculation in shell theorem is that HS attracts M but M doesnt attract HS.

SPLIT ANALYSIS of HS amd M

When HS is a gravitating mass and M is a falling mass
Mass on one side is closer, but there is more mass on another side.

There are three masses and three centers of gravities cg

A represents the cg of Closer mass
B represents the cg More mass
C represents the cg of M

The distance between A and C is h
The distance between B and C is h1

Obviously, h1 > h. The entire spherical shell exerts zero net force on M OK for the sake of arguments BUT the entire M also exerts a force on Closer mass as well as More mass of the HS. Here

When M is a gravitating mass and HS is a falling mass
Closer mass of HS falls on M with g of M
More mass of HS also falls on M with g of M
As h < h1 therefore the value of "g" of M at A > the value of "g" of M at B. Since net pull of M on two different parts of HS is not zero, therefore, Closer mass falls on M with little bit resistance from more mass of HS

Conclusion: Accelerations due to gravities of Closer mass and More mass of HS may be cancelled at the center of M BUT the value of g of M at A is greater than the value of g of M at B due to the difference in heights therefore movement happens because of unbalance pull of M on two parts of the HS
(https://s26.postimg.org/san2v3zsp/IMG_1017.jpg)

(https://s26.postimg.cc/nhdusb0sp/IMG_1017.jpg)
Title: Re: Are all masses like black holes?
Post by: Macarios on February 19, 2018, 12:53:30 PM
If feather and hammer fall together, they hit Earth together, because they have combined pull and Earth intercepts them together.
If they fall in succession, one and then another, hammer would in deed fall a tiny bit faster, but that tiny bit is many times tinier than our measuring abilities.
Mathematically it can be shown, but there is no way (not even slightest chance) to measure such small difference in reality.
Title: Re: Are all masses like black holes?
Post by: Shifter on February 19, 2018, 02:12:50 PM
If feather and hammer fall together, they hit Earth together, because they have combined pull and Earth intercepts them together.
If they fall in succession, one and then another, hammer would in deed fall a tiny bit faster, but that tiny bit is many times tinier than our measuring abilities.
Mathematically it can be shown, but there is no way (not even slightest chance) to measure such small difference in reality.

Wrong
That's like saying someone with an open parachute and someone without a parachute will land at the same time.

Aerodynamics and the much lighter weight of the feather could result in the feather being picked up by the wind and not landing somewhere else a long time after.

Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 03:52:51 PM
Quote
If feather and hammer fall together, they hit Earth together, because they have combined pull and Earth intercepts them together.
If they fall in succession, one and then another, hammer would in deed fall a tiny bit faster, but that tiny bit is many times tinier than our measuring abilities.
Mathematically it can be shown, but there is no way (not even slightest chance) to measure such small difference in reality.
- i think you missed one of my previous posts regarding hammer and feather

Try feather and hammer separately from the same altitude

case#1: Drop feather from the same height h on earth
Split Analysis of Feather and Earth

Feather falls on earth due to ge of earth
Earth falls on feather due gf of feather - Earth can be seen from feather

Case #2 Drop hammer from the same height h on earth
Split Analysis of Hammer and Earth

Hammer falls on earth due to ge of earth
Earth falls on Hammer due to gh of Hammer - Earth can be seen from Hammer

Since ge > gh > gf therefore earth falls on hammer at greater accelaration than falls on feather - quite simple

Earth moves towards hammer if both hammer and feather drop at the same time from the same altitude on antipodes 
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 04:39:16 PM
Since ge > gh > gf therefore earth falls on hammer at greater accelaration than falls on feather - quite simple

Earth moves towards hammer if both hammer and feather drop at the same time from the same altitude on antipodes
Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?

All you talk of separate ge , gh and gf is a totally ridiculous waste of time because the typical masses would be:If you have any concept of relative values you  might get the message.

PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.
Title: Re: Are all masses like black holes?
Post by: Shifter on February 19, 2018, 05:46:14 PM
Since ge > gh > gf therefore earth falls on hammer at greater accelaration than falls on feather - quite simple

Earth moves towards hammer if both hammer and feather drop at the same time from the same altitude on antipodes
Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?

All you talk of separate ge , gh and gf is a totally ridiculous waste of time because the typical masses would be:
  • Earth: 5.972 1024 kg,
  • Hammer: 2 kg and
  • Pigeon Tail Feather: 50 mg.
If you have any concept of relative values you  might get the message.

PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.

Where is it falling? Obviously must be gravitationally affected by something which in turn means the object with heavier mass is pulling on that object more than the object with a lighter mass. Also the object with a lighter mass will be gravitationally affected by the falling object that is heavier. An infinitesimal amount sure but enough that God himself would consider it a variable in the experiment. The idea of experiments is to eliminate the variables
Title: Re: Are all masses like black holes?
Post by: Twerp on February 19, 2018, 06:00:21 PM
Since ge > gh > gf therefore earth falls on hammer at greater accelaration than falls on feather - quite simple

Earth moves towards hammer if both hammer and feather drop at the same time from the same altitude on antipodes
Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?

All you talk of separate ge , gh and gf is a totally ridiculous waste of time because the typical masses would be:
  • Earth: 5.972 1024 kg,
  • Hammer: 2 kg and
  • Pigeon Tail Feather: 50 mg.
If you have any concept of relative values you  might get the message.

PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.

And if they were being dropped from the same location at the same time, their combined mass would act on the earth so they would still hit the earth simultaneously. EEK thinks he has discovered something noteworthy but it is in fact extraordinarily insignificant.
Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 07:13:33 PM
Quote
Whatever you claim Newton's Shell Theorem is correct
Quote
EEK thinks he has discovered something
- Neither claim nor discovery but its just a truth

Quote
PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.
What do you think if the "g" of M >>>>>>> the "g" of HS? For Example, Earth (ideally sphere) inside a homogeneous HS. The "g" of earth >>>>>>>> the "g" HS
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 08:52:09 PM
Since ge > gh > gf therefore earth falls on hammer at greater accelaration than falls on feather - quite simple

Earth moves towards hammer if both hammer and feather drop at the same time from the same altitude on antipodes
Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?

All you talk of separate ge , gh and gf is a totally ridiculous waste of time because the typical masses would be:
  • Earth: 5.972 1024 kg,
  • Hammer: 2 kg and
  • Pigeon Tail Feather: 50 mg.
If you have any concept of relative values you  might get the message.

PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.

Where is it falling? Obviously must be gravitationally affected by something which in turn means the object with heavier mass is pulling on that object more than the object with a lighter mass. Also the object with a lighter mass will be gravitationally affected by the falling object that is heavier. An infinitesimal amount sure but enough that God himself would consider it a variable in the experiment. The idea of experiments is to eliminate the variables
I did ask E E K, "Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?"

But no, "The idea of experiments is" not "to eliminate the variables", but to find the magnitude of their effects.
Maybe that does eliminate the variable, but it might also simply mean that effect of the variable is too small for that experimental method to resolve.

Exactly that happened to the early proposals for the heliocentric solar system.
Aristarchus of Samos proposed it, but it was rejected because it was reasoned, correctly, that the annual motion of the sun should cause stellar parallax. As no stellar parallax could be observed, heliocentrism was rejected.
Again, Copernicus proposed heliocentrism, but it was rejected, at least by Tycho Brahe because even with his far more accurate measurements he still observed no stellar parallax.

But this stellar parallax was finally observed and was far smaller than Tycho Brahe could have ever measured without a telescope. The largest stellar parallax of only of 0.772-arcsec is for Proxima Centauri.

One reason for doing such calculations is to get some idea of what precision is required in the experiment.
Of course neither Aristarchus of Samos nor Tycho Brahe could have made these calculations, but for these fall times, we can.

Possibly a simple manual drop an a stop-watch would be adequate.
Then maybe a sophisticated electronically controlled drop mechanism coupled to a high precision electronic timer might be needed.

 ;D :D So, maybe you could calculate those times and let's know what equipment might be needed to measure the times. :D ;D
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 09:10:13 PM
Quote
Whatever you claim Newton's Shell Theorem is correct
Quote
EEK thinks he has discovered something
- Neither claim nor discovery but its just a truth

Quote
PS: Whatever you claim Newton's Shell Theorem is correct and the gravity inside a spherical shell, due to that shell is zero.
What do you think if the "g" of M >>>>>>> the "g" of HS? For Example, Earth (ideally sphere) inside a homogeneous HS. The "g" of earth >>>>>>>> the "g" HS
If the earth, of mass say Me, were inside and concentric with a huge HS of any mass, say mHS, then:Your ">>>>>>>>" is unnecessary, provided the geometries are perfect the result applies to any masses.

I hope this is close enough to what you were asking.
Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 09:27:14 PM
Quote
I did ask E E K, "Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?"

Earth and hammer will strike first if aforementioned both hammer and feather dropped at the same time from the same altitude but on antipodes - It's all about the concept of idea, not calculation

EDIT: However, all objects may free fall at the same rate regardless of their mass if it is the natural tendency of smaller objects to drive towards a massive object in the region.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 10:06:27 PM
Quote
I did ask E E K, "Would you now calculate how long it would take a hammer of mass 1 kg and a feather of mass 0.05 g to fall 10 m in a perfect vacuum?"

Earth and hammer will strike first if aforementioned both hammer and feather drop at the same time from the same altitude but on antipodes - It's all about the concept, not calculation
But the difference is so small that there not the slightest chance of even
No scientific theories would ever be claimed valid to that precision.
An error in altitude by the diameter of a proton would cause about 1000 times as much error, so you stick your concepts and I'll worry about things that matter.

If, instead of earth, your were talking about a metre diameter sphere of rock, a one kilogram hammer and a feather isolated in space, it might be a different matter.
Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 10:17:22 PM
As said in above Edit:

All objects may free fall at the same rate regardless of their mass if it is the natural tendency of smaller objects to drive towards a massive object in the region.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 10:53:41 PM
As said in above Edit:

All objects may free fall at the same rate regardless of their mass if it is the natural tendency of smaller objects to drive towards a massive object in the region.
There is no "natural tendency"
It's simply a result of gravitation applying the same force (though in opposite directions) to each object, so that the amount they move is inversely proportional to their mass.

What you have been saying about the earth, hammer and feather was"correct in principle", but the difference im masses is so massive that for all intents and purposes the earth does not move.

The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Quote from: Wikipedia
Barycenter
Rather than appearing to orbit a common center of mass with the smaller body, the larger will simply be seen to wobble slightly. This is the case for the EarthMoon system, where the barycenter is located on average 4,671 km (2,902 mi) from the Earth's center, well within the planet's radius of 6,378 km (3,963 mi).
(https://upload.wikimedia.org/wikipedia/commons/5/59/Orbit3.gif)
Two bodies with a major difference
in mass orbiting a common
barycenter internal to one body
(similar to the EarthMoon system)
distances not to scale


Title: Re: Are all masses like black holes?
Post by: E E K on February 19, 2018, 11:10:36 PM
Quote
The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Freedom of choice - Choose what is right for You
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 19, 2018, 11:27:40 PM
Quote
The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Freedom of choice - Choose what is right for You
But that doesn't make your choice correct, though in this Trump era, with it's fake-fax and alternate-fax, who knows?
Title: Re: Are all masses like black holes?
Post by: Macarios on February 20, 2018, 12:14:42 AM
If feather and hammer fall together, they hit Earth together, because they have combined pull and Earth intercepts them together.
If they fall in succession, one and then another, hammer would in deed fall a tiny bit faster, but that tiny bit is many times tinier than our measuring abilities.
Mathematically it can be shown, but there is no way (not even slightest chance) to measure such small difference in reality.

Wrong
That's like saying someone with an open parachute and someone without a parachute will land at the same time.

Aerodynamics and the much lighter weight of the feather could result in the feather being picked up by the wind and not landing somewhere else a long time after.

Thanks, but EEK was talking of hypothetical situation without air or other object in vicinity.

The example with hammer and feather was about free fall in vacuum.
That was what Apollo astronaut did on the Moon.
Same as feather and bowling ball in that giant vacuum chamber.

We all know that in air there is air drag.
Title: Re: Are all masses like black holes?
Post by: E E K on February 20, 2018, 12:34:38 PM
Quote
The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Gravitational force between sun and moon; F1 = GMm/d^2; where M = mass of sun R = radius of sun and m= mass of moon

Gravitational force between earth and moon; F2 = GMm/d^2; where M = mass of earth R = radius of earth, and m = mass of moon

Since F1 > F2 after calculation therefore shouldnt moon revolve the sun in its separate orbit?

Gravitational force between earth and sun; F = GMm/d^2; where M = mass of sun, R = radius of sun and m= mass of earth

Gravitational acceleration of sun; gs = GM/R^2 ;
Earth revolves in its orbit due to gs = GM/R^2,

Doesnt earth change its acceleration (in reference to the gs=GM/d^2 of sun) due to the barycenter of earth and moon in its orbit around the sun?
Title: Re: Are all masses like black holes?
Post by: E E K on February 20, 2018, 12:41:19 PM
Quote
That was what Apollo astronaut did on the Moon.
It might be true if they really went to the moon but the mass or the gravity of the moon is still unknown according to the mainstream science.  Had you missed one of my posts? Here

https://www.theflatearthsociety.org/forum/index.php?topic=74238.0 (https://www.theflatearthsociety.org/forum/index.php?topic=74238.0)
Title: Re: Are all masses like black holes?
Post by: Macarios on February 20, 2018, 01:26:34 PM
Quote
The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Gravitational force between sun and moon; F1 = GMm/d^2; where M = mass of sun R = radius of sun and m= mass of moon

Gravitational force between earth and moon; F2 = GMm/d^2; where M = mass of earth R = radius of earth, and m = mass of moon

Since F1 > F2 after calculation therefore shouldnt moon revolve the sun in its separate orbit?

Gravitational force between earth and sun; F = GMm/d^2; where M = mass of sun, R = radius of sun and m= mass of earth

Gravitational acceleration of sun; gs = GM/R^2 ;
Earth revolves in its orbit due to gs = GM/R^2,

Doesnt earth change its acceleration (in reference to the gs=GM/d^2 of sun) due to the barycenter of earth and moon in its orbit around the sun?

You are using the same letter "d" for distance in all formulas.
I hope you haven't forgot that distance between Sun and Moon is much greater than distance between Earth and Moon.

And what orbits the Sun is actually the barycenter that Earth and Moon revolve together.
Distance between center of Earth and barycenter is just 27 ppm of the distance between Earth and Sun.
It is 0.0027 percent, so if you disregard it you are still pretty accurate.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 20, 2018, 01:36:46 PM
Quote
That was what Apollo astronaut did on the Moon.
It might be true if they really went to the moon but the mass or the gravity of the moon is still unknown according to the mainstream science.  Had you missed one of my posts? Here

https://www.theflatearthsociety.org/forum/index.php?topic=74238.0 (https://www.theflatearthsociety.org/forum/index.php?topic=74238.0)
Incorrect. The mass and gravity of the moon were calculated approximately long ago from the tidal effect on earth and from the position of the earth-moon barycentre.

Then, once spacecraft were sent to the vicinity of the moon, the mass and gravity could be calculated very accurately.
Quote from: Wikipedia
The Soviet Union sent the first spacecraft to the vicinity of the Moon, the robotic vehicle Luna 1, on January 4, 1959. It passed within 6,000 kilometres (3,200 nmi; 3,700 mi) of the Moon's surface, but did not achieve lunar orbit. Luna 3, launched on October 4, 1959, was the first robotic spacecraft to complete a circumlunar free return trajectory, still not a lunar orbit, but a figure-8 trajectory which swung around the far side of the Moon and returned to the Earth. This craft provided the first pictures of the far side of the Lunar surface.

The Soviet Luna 10 became the first spacecraft to actually orbit the Moon in April 1966. It studied micrometeoroid flux, and lunar environment until May 30, 1966.

The first United States spacecraft to orbit the Moon was Lunar Orbiter 1 on August 14, 1966. The first orbit was an elliptical orbit, with an apolune of 1,008 nautical miles (1,867 km; 1,160 mi) and a perilune of 102.1 nautical miles (189.1 km; 117.5 mi).[5] Then the orbit was circularized at around 170 nautical miles (310 km; 200 mi) to obtain suitable imagery. Five such spacecraft were launched over a period of thirteen months, all of which successfully mapped the Moon, primarily for the purpose of finding suitable Apollo program landing sites.
Title: Re: Are all masses like black holes?
Post by: E E K on February 20, 2018, 04:15:28 PM
Quote
You are using the same letter "d" for distance in all formulas.
- I presumed you all know that at this stage.

1 ppm or 27 ppm but doesn't it change the "g" of the sun which causes the orbital motion of the earth as F = GMm/d^2 where M = mass of sun, m = mass of earth and d=o/c center between earth and sun. Even if it is disregarded then what is the speed of this barycenter (combined effect of earth and moon) which orbits the sun and how would you apply the universal law of gravitation to it and sun?
Title: Re: Are all masses like black holes?
Post by: E E K on February 20, 2018, 04:23:17 PM
Quote
incorrect. The mass and gravity of the moon were calculated approximately long ago from the tidal effect on earth and from the position of the earth-moon barycentre.

Your claim is unbeknownst to me but none of the celestial bodies mass or gravity is known as per aforesaid link.
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 20, 2018, 08:51:08 PM
Quote
incorrect. The mass and gravity of the moon were calculated approximately long ago from the tidal effect on earth and from the position of the earth-moon barycentre.

Your claim is unbeknownst to me but none of the celestial bodies mass or gravity is known as per aforesaid link.
According to what link, this one, Does "g =GM/d^2" best in situ in mathematical equation of "F = GMm/d^2 = mg"? (https://www.theflatearthsociety.org/forum/index.php?topic=74238.0)?
I see nothing there that shows that "none of the celestial bodies mass or gravity is known".

If not that link, which do you mean?

It is comparitively easy to calculate the mass of any body with one or more orbiting satellites
If the size of the body is known, its mass can also by calculated if an object can be observed falling into it.
Both of these methods were used to determine the mass of the moon even before any unmanned craft soft landed on the moon..
Title: Re: Are all masses like black holes?
Post by: E E K on February 20, 2018, 09:13:04 PM
Quote
It is comparitively easy to calculate the mass of any body with one or more orbiting satellites
If the size of the body is known, its mass can also by calculated if an object can be observed falling into it.
Both of these methods were used to determine the mass of the moon even before any unmanned craft soft landed on the moon..
How or Any reference
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 20, 2018, 09:35:39 PM
Quote
It is comparitively easy to calculate the mass of any body with one or more orbiting satellites
If the size of the body is known, its mass can also by calculated if an object can be observed falling into it.
Both of these methods were used to determine the mass of the moon even before any unmanned craft soft landed on the moon..
How or Any reference
Easy, peasy: How do scientists measure or calculate the weight of a planet? (https://www.scientificamerican.com/article/how-do-scientists-measure/)
Or: Ask an Astronomer, How do you measure a planet's mass? (Beginner) (http://curious.astro.cornell.edu/physics/57-our-solar-system/planets-and-dwarf-planets/orbits/245-how-do-you-measure-a-planet-s-mass-beginner)
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 20, 2018, 10:38:52 PM
Quote
The moon is big enough to have a significant and the earth-moon system orbits a common centre, the barycentre,
Gravitational force between sun and moon; F1 = GMm/d^2; where M = mass of sun R = radius of sun and m= mass of moon
Gravitational force between earth and moon; F2 = GMm/d^2; where M = mass of earth R = radius of earth, and m = mass of moon

Since F1 > F2 after calculation therefore shouldnt moon revolve the sun in its separate orbit?
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I'll edit your equations to make it easier for me to follow. I hope it keeps your intent:
Gravitational force between sun and moon: Fsm = GMsunmm/Rsm2; where Msun = mass of sun, Rsm = radius of moon's orbit about sun and mm = mass of moon

Gravitational force between earth and moon: Fem = Gmemm/Rem2; where me = mass of earth, Rem = radius of moon's orbit about earth, and mm = mass of moon

Since Fsm > Fem after calculation therefore shouldnt moon revolve the sun in its separate orbit?

This bit is a very good question and is more than enough for one answer.

Part of the answer is that, as you say, the sun's gravitational field (gravity) near earth is greater than the gravitation field of the earth at the moon.
The sun's gravitational field (gravity) near the earth, however, changes only slightly over the radius of the moon's orbit around the earth.
In other words, the whole earth-moon system is attracted by the sun by almost the same amount, so the moon orbits the earth.
But, the earth-moon system travels around the sun at a much higher tangential velocity than the moon's velocity around the earth.

So the motion is an orbit around the sun at the same radius as the earth with just a little wriggle, with a period on one month, to make it orbit the earth.
This diagram, to scale, shows just half a month.
(https://www.wired.com/images_blogs/wiredscience/2012/12/earthmoonpath.jpeg)
This just shows half a month. If I wanted to show a longer
time period, the motion of the Earth and moon around the
Sun would make it super-difficult to see the motion of the
moon relative to the Earth.
Read in detail in: WIRED, Does the Moon Orbit the Sun or the Earth? (https://www.wired.com/2012/12/does-the-moon-orbit-the-sun-or-the-earth/)

There are many more references on this, as at first it seems a little puzzling.
Physics Stack Exchange, Why does the moon not revolve around the sun directly? (https://physics.stackexchange.com/questions/92465/why-does-the-moon-not-revolve-around-the-sun-directly)
Then one that brings in Gravity Wells, EXPLAIN xkcd, Gravity Wells (https://www.explainxkcd.com/wiki/index.php/681:_Gravity_Wells).
And there are plenty more. Just search for "Why does moon orbit the earth and not the sun?".
Title: Re: Are all masses like black holes?
Post by: E E K on February 21, 2018, 07:52:41 PM
Quote
easy peasy
The only way we can measure a planet's mass is through its gravity as per your link  - This needs a gravity model free of mathematical errors.

Quote
Since Fsm > Fem after calculation therefore shouldnt moon revolve the sun in its separate orbit?

There are 4 possibilities in the current model - impov

1- When the earth is in between the sun and moon: Shouldn't the combined effect of earth and sun alter the orbit of the moon and its speed as well

2- when the moon is in between earth and sun: Either Moon should fall to the sun instead of earth or at least there should be a reduction in its speed and the change in its orbit around the earth

3- Moon should revolve the sun in its separate orbit instead of orbiting the earth

4- The current orbit of the earth around the sun doesn't fit for both earth and moon if there is a combined effect of binary plates (earth and moon) on sun
Title: Re: Are all masses like black holes?
Post by: Alpha2Omega on February 21, 2018, 08:15:10 PM
Quote
easy peasy
The only way we can measure a planet's mass is through its gravity as per your link  - This needs a gravity model free of mathematical errors.

Errors limit the precision we're capable of obtaining, but if the errors (or unknowns) are reasonably small, the precision can be reasonably high.

Quote
Quote
Since Fsm > Fem after calculation therefore shouldnt moon revolve the sun in its separate orbit?

The moon is actually orbiting the sun. Its orbit is significantly perturbed by the earth, however. From the point of view of the earth, the moon appears to revolve around it. From the POV of the sun, earth and moon appear to alternately overtake each other, slightly speed up, slow down, get nearer and farther away, and follow a braided path, while the barycenter (center of mass) of the earth-moon system follows a smooth orbit.

Quote
There are 4 possible case according to current model - impov

1- When the earth is in between the sun and moon: Shouldn't the combined effect of earth and sun alter the orbit of the moon and its speed as well

2- when the moon is in between earth and sun: Either Moon should fall to the sun instead of earth or at least there should be a reduction in its speed and the change in its orbit around the earth

3- Moon should revolve the sun in its separate orbit instead of orbiting the earth

4- The current orbit of the earth around the sun doesn't fit for both earth and moon if there is a combined effect of binary plates (earth and moon) on sun

This is a three-body problem. Keplerian orbits only apply to two bodies, not more. Solving three-body problems (or, more generally, N-body problems for N > 2) is not trivial; it can only be done numerically, but it can be done (for N < some fairly large number).
Title: Re: Are all masses like black holes?
Post by: E E K on February 21, 2018, 08:45:34 PM
Quote
Errors limit the precision we're capable of obtaining, but if the errors (or unknowns) are reasonably small, the precision can be reasonably high.

All objects free fall at the same rate regardless of their mass - we don't notice because objects are very small as compared to earth

Is it possible for an imaginary earth to free fall at the same rate?

The "g" of the imaginary earth is equal to the "g" real earth but in opposite direction - so guess?

if not then how is it possible to calculate the "Mass of the Earth" in the following link?

http://www.citycollegiate.com/gravityXa.htm
Title: Re: Are all masses like black holes?
Post by: rabinoz on February 21, 2018, 09:35:51 PM
Quote
easy peasy
The only way we can measure a planet's mass is through its gravity as per your link  - This needs a gravity model free of mathematical errors.
There are no known mathematical errors, apart from using Newtonian Gravitation in lieu of General Relativity. Apart from a minute discrepancy in the precession of the perihelion of the planet Mercury GR is not necessary.
There are some "errors" from other planets, but they are very small and depend on the inverse cube of the distance to the other object not the inverse square.
In any case, they can be corrected for when doing a detailed numerical simulation - a closed solution with three or more bodies is as yet not possible.

Quote from: E E K
Quote
Since Fsm > Fem after calculation therefore shouldnt moon revolve the sun in its separate orbit?
This was my answer to that question from the previous post:

This bit is a very good question and is more than enough for one answer.

Part of the answer is that, as you say, the sun's gravitational field (gravity) near earth is greater than the gravitation field of the earth at the moon.
The sun's gravitational field (gravity) near the earth, however, changes only slightly over the radius of the moon's orbit around the earth.
In other words, the whole earth-moon system is attracted by the sun by almost the same amount, so the moon orbits the earth.
But, the earth-moon system travels around the sun at a much higher tangential velocity than the moon's velocity around the earth.

So the motion is an orbit around the sun at the same radius as the earth with just a little wriggle, with a period on one month, to make it orbit the earth.
This diagram, to scale, shows just half a month.
(https://www.wired.com/images_blogs/wiredscience/2012/12/earthmoonpath.jpeg)
This just shows half a month. If I wanted to show a longer
time period, the motion of the Earth and moon around the
Sun would make it super-difficult to see the motion of the
moon relative to the Earth.
Read in detail in: WIRED, Does the Moon Orbit the Sun or the Earth? (https://www.wired.com/2012/12/does-the-moon-orbit-the-sun-or-the-earth/)

There are many more references on this, as at first it seems a little puzzling.
Physics Stack Exchange, Why does the moon not revolve around the sun directly? (https://physics.stackexchange.com/questions/92465/why-does-the-moon-not-revolve-around-the-sun-directly)
Then one that brings in Gravity Wells, EXPLAIN xkcd, Gravity Wells (https://www.explainxkcd.com/wiki/index.php/681:_Gravity_Wells).
And there are plenty more. Just search for "Why does moon orbit the earth and not the sun?".[/b]
Quote from: E E K

There are 4 possibilities in the current model - impov

1- When the earth is in between the sun and moon: Shouldn't the combined effect of earth and sun alter the orbit of the moon and its speed as well

2- when the moon is in between earth and sun: Either Moon should fall to the sun instead of earth or at least there should be a reduction in its speed and the change in its orbit around the earth
There will be some effect, but what matters is not the absolute value os the sun's gravitational field near the earth, but on how much it changes during the moon's orbit.
The sun's "gravity" at the barycentre of the earth/moon system is what keeps the earth/moon system in orbit around the sun.

Quote from: E E K
3- Moon should revolve the sun in its separate orbit instead of orbiting the earth
No it shouldn't! That has been shown in all the above references.
It is not as though the moon is sitting stationary 384,400 km from the earth between the earth and the sun, it is orbiting the earth.
So half a lunar orbit later it will be on the far side of the earth, so being pulled closer to the earth.
In one orbit, the effects of the sun's gravitation cancel out.

Don't forget that
Quote
Out here, at the distance we orbit the sun, the gravitational pull of the sun is only 0.0006 of the strength of the earth's gravity on the surface of the earth.
or about 0.006 m/s2.

Quote from: E E K
4- The current orbit of the earth around the sun doesn't fit for both earth and moon if there is a combined effect of binary plates (earth and moon) on sun
It does fit perfectly well, though I can't follow your "combined effect of binary plates (earth and moon) on sun" is meant to mean.
Title: Re: Are all masses like black holes?
Post by: E E K on March 01, 2018, 11:28:08 AM
Quote
It does fit perfectly well, though I can't follow your "combined effect of binary plates (earth and moon) on sun" is meant to mean.

We are going off the topic but shouldn't the radius of the orbit of binary planets (earth and moon) be greater than the greater current orbit of earth due to the combined effect.
Although binary planets (earth and moon) orbit around the sun but half of the moon cycle is in opposite direction while half of its cycle is along the direction of motion of barycentre in its orbit around the sun. So my question is why the orbital motion of the moon around earth doesnt affect the speed as well as the position of barycentre around the sun in its orbit if the moon is influenced by both the g of sun and earth?
Title: Re: Are all masses like black holes?
Post by: rabinoz on March 01, 2018, 04:38:20 PM
Quote
It does fit perfectly well, though I can't follow your "combined effect of binary plates (earth and moon) on sun" is meant to mean.

We are going off the topic but shouldn't the radius of the orbit of binary planets (earth and moon) be greater than the greater current orbit of earth due to the combined effect.
What "combined effect"? Between the earth and moon, there is one gravitational force, Fem = G x Me x m[/i]m/dem2, where dem is the distance between the "centres of gravity" (simply the centres if they are spherically symetrical).
There is no separate Fme, that is the same force as Fem. It's almost as though gravitation were a piece of hypothetical elastic with force inversely proportional length squared.

Quote from: E E K
Although binary planets (earth and moon) orbit around the sun but half of the moon cycle is in opposite direction while half of its cycle is along the direction of motion of barycentre in its orbit around the sun. So my question is why the orbital motion of the moon around earth doesnt affect the speed as well as the position of barycentre around the sun in its orbit if the moon is influenced by both the g of sun and earth?
For the earth-moon system what matters is not the absolute value of the sun's gravity near earth, but only the changes in that field around the moon's orbit.

So while the sun's gravity near the moon is about 0.0059 m/s2 and the earth's in only about 0.0027 m/s2 the variation in the sun's gravity is only about 1% of the earth's gravity at the moon.
         moon-sun (km)        Gravm-s         Change in Gravm-s        Gravm-e
min     149.3 x 106          0.00595 m/s2     0.000031 m/s2           0.0027 m/s2
avg     149.7 x 106          0.00592 m/s2      0.000000 m/s2           0.0027 m/s2
max    150.1 x 106          0.00589  m/s2    -0.000030 m/s2           0.0027 m/s2
So they are all affected, but only very slightly.