How I think of gravity!
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05-07-2013, 07:53 PM
Lightbulb How I think of gravity!
The mass and density of an object in space both affect the gravitational field around an object. Density effects the force of the pull, and mass effects the distance the pull reaches.

Einstein said that massive objects curve the space-time around them (and he was right).

This is a wicked idea because space is 3 dimensional, and to think about bending a 3 dimensional space is crazy.

I often try to wrap my head around it, and this is how I think of it while lying in bed at night.

I think of space as having many lattice (each one stretches into space infinitely) lines all stacked on top of each other, each with a specific coordinate, and each with little to no space between each other (the most accurate image of this that I found is picture #1, mind the connected cubes).

If a massive and dense object is resting on top of these lattice lines, all of the others around it are affected to a certain point (think of sitting in the middle of a bed, your weight causes the middle to sink in, and it also affects the area around the middle).

Now, this causes the curve in space-time!

Still there is a problem, the lattice lines are obviously invisible (I'm not saying my theory is correct) but they can be interacted with, but also they don't get in the way of things occupying its space (meaning that objects can move through them, but they are still affected by the object)

Now, all of space is composed of these lattice lines, but they are invisible (I already went over this, just clarifying).

This would allow for any 3 dimensional object to bend the 3 dimensional space, and the time that is interconnected with it.

The more massive the object occupying the space, the more lattice lines it affects, and the more dense an object is, the more the lattice lines dip and bend with the object.

Shocking I hope you all could follow my blather and drivel.

I will also work in a 3d program to accurately represent my model of gravity.

Here is picture #1 (mind the cubes in it, and remember the space between the lattice lines is infinitesimally small!)
[Image: Lattice___Lines_Background_by_Delorfirith.jpg]
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05-07-2013, 08:19 PM
RE: How I think of gravity!
(05-07-2013 07:53 PM)UndercoverAtheist Wrote:  The mass and density of an object in space both affect the gravitational field around an object. Density effects the force of the pull, and mass effects the distance the pull reaches.

Einstein said that massive objects curve the space-time around them (and he was right).

This is a wicked idea because space is 3 dimensional, and to think about bending a 3 dimensional space is crazy.

I often try to wrap my head around it, and this is how I think of it while lying in bed at night.

I think of space as having many lattice (each one stretches into space infinitely) lines all stacked on top of each other, each with a specific coordinate, and each with little to no space between each other (the most accurate image of this that I found is picture #1, mind the connected cubes).

If a massive and dense object is resting on top of these lattice lines, all of the others around it are affected to a certain point (think of sitting in the middle of a bed, your weight causes the middle to sink in, and it also affects the area around the middle).

Now, this causes the curve in space-time!

Still there is a problem, the lattice lines are obviously invisible (I'm not saying my theory is correct) but they can be interacted with, but also they don't get in the way of things occupying its space (meaning that objects can move through them, but they are still affected by the object)

Now, all of space is composed of these lattice lines, but they are invisible (I already went over this, just clarifying).

This would allow for any 3 dimensional object to bend the 3 dimensional space, and the time that is interconnected with it.

The more massive the object occupying the space, the more lattice lines it affects, and the more dense an object is, the more the lattice lines dip and bend with the object.

Shocking I hope you all could follow my blather and drivel.

I will also work in a 3d program to accurately represent my model of gravity.

Here is picture #1 (mind the cubes in it, and remember the space between the lattice lines is infinitesimally small!)
[Image: Lattice___Lines_Background_by_Delorfirith.jpg]

If you think you understand Quantum Theory, you do not understand Quantum Theory.

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05-07-2013, 08:31 PM
RE: How I think of gravity!
The classic analogy for the bending of spacetime is to consider a two-dimensional surface - such as, say, the top of a mattress. Putting an object on top of it will warp it (create depressions). Then, any smaller object on the surface will tend to fall into those depressions. You actually mentioned this already!

So it sounds like you've been trying to visualize this kind of behaviour in three dimensions. And from a decent starting point (there's a reason field lines are used to conceptualize so many things...).

One traditional way to do so is with a colour map; we can all picture three-dimensional space pretty well, so the addition is to shade the area in accordance with the strength of the distortion there (so, 'free' space is, say, white, and a singularity is, of course, black). So, the degree of warping of the underlying spacetime is visualized as shading and spectra. Then if you can imagine turning that around in your head, it'll give, essentially, a two-dimensional projection at any point (you're still looking at it from one direction!) - but the viewpoint is free, so the sum total of those is pretty good for conceptualizing the full three dimensions.

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05-07-2013, 10:12 PM
RE: How I think of gravity!
I'm so friggin' interested in this stuff, but my head wants to roll right off of my shoulders when I try to understand shit like the warping of space/time. I can get the gist of things, but I can never really get a handle on exactly what's going on. Relativity still gives me fits. It's just so counterintuitive. But I love it that we can understand such complex ideas and use them. I just wish my brain was wired to be able to see it and go, oh yeah, that makes sense. Because it just doesn't. I envy you smart asses that get it easily. Consider

But now I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth.

~ Umberto Eco
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06-07-2013, 06:51 AM
RE: How I think of gravity!
(05-07-2013 07:53 PM)UndercoverAtheist Wrote:  The mass and density of an object in space both affect the gravitational field around an object. Density effects the force of the pull, and mass effects the distance the pull reaches.

Einstein said that massive objects curve the space-time around them (and he was right).

This is a wicked idea because space is 3 dimensional, and to think about bending a 3 dimensional space is crazy.

The mass doesn't really affect the distance of the pull. If you double the mass, to get the same amount of force before the doubling, you go square root of 2 times as far.

The density doesn't affect the force of the pull. If somehow you could instantaneously compress the earth to the size of a baseball, a person located where the surface of the earth used to be would experience the same gravitational force both before and after the compression of the earth. The only role density has is to allow you to get closer to the center of mass of an object that is more dense. So a black hole, which is a collapsed star that has become uber dense, can trap light that gets close enough. But no light will be trapped that passes outside the original spacial extent of the star.

All that aside, Einstein was in a league of his own. General relativity is an amazing theory that has made numerous incredible predictions, all of which have proven true. Since this is an atheist blog, I can't resist comparing the awesome discoveries of science to the burning bush revelations of the Bible and conclude religion comes up short.
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06-07-2013, 08:44 AM (This post was last modified: 06-07-2013 08:48 AM by UndercoverAtheist.)
RE: How I think of gravity!
(06-07-2013 06:51 AM)BryanS Wrote:  
(05-07-2013 07:53 PM)UndercoverAtheist Wrote:  The mass and density of an object in space both affect the gravitational field around an object. Density effects the force of the pull, and mass effects the distance the pull reaches.

Einstein said that massive objects curve the space-time around them (and he was right).

This is a wicked idea because space is 3 dimensional, and to think about bending a 3 dimensional space is crazy.

The mass doesn't really affect the distance of the pull. If you double the mass, to get the same amount of force before the doubling, you go square root of 2 times as far.

The density doesn't affect the force of the pull. If somehow you could instantaneously compress the earth to the size of a baseball, a person located where the surface of the earth used to be would experience the same gravitational force both before and after the compression of the earth. The only role density has is to allow you to get closer to the center of mass of an object that is more dense. So a black hole, which is a collapsed star that has become uber dense, can trap light that gets close enough. But no light will be trapped that passes outside the original spacial extent of the star.

All that aside, Einstein was in a league of his own. General relativity is an amazing theory that has made numerous incredible predictions, all of which have proven true. Since this is an atheist blog, I can't resist comparing the awesome discoveries of science to the burning bush revelations of the Bible and conclude religion comes up short.

What you said really isn't making any sense at all (aside from the mass affecting distance, you are correct when it comes to that).

I've studied black holes enough to know that the stars matter collapses in on itself to create an incredibly dense point, creating a singularity. The singularity is incredibly dense, and affects the amount of force it has once you get over the event horizon (so density affects force of gravity, eh?).

Also, think about a planet like Jupiter, not very dense, but massive. This mass allows it's gravitational field to reach out, grabbing space debris. At one point, jupiter might have acted like our sun did, grabbing space debris and colliding them within its gravitational lock. These space debris eventually became Jupiter's moons.

Now, if Jupiter had been a lot smaller, but with the same density, it would not have attracted those space debris and created moons for itself. Of course, it would have a few moons because of its density (it would have had a lot more force for its mass, so the same sized object that jupiter has could have been in orbit around the small jupiter, but not as many because the mass had decreased).

Oh, and your earth analogy is wrong. If you shrunk the earth down to the size of a baseball, a person located on it would be closer to the core, in turn making the force on his body over what we are experiencing now.

People all over the internet say that density does not affect gravity in any way.

Then I look at a star, and then I look at that star's black hole. Light can escape the star, light cannot escape a black hole. Meaning that the density of the object did affect the 3 dimensional plane of gravity in a way that light cannot even escape its tug.

"Think about the center of mass. The formula for universal gravitation has that r on the bottom. If the star becomes smaller but loses no mass, then things can get closer and have a much larger force applied on each other. Light can get closer to the center of mass and therefore would not escape this much larger force.

So in a way, this increase in density actually does affect gravity, but it's not the change in density that does it, it's the means by which it achieves this increased density that explains the increase in force." - Person on yahoo answers that explained it more eloquently than my insane drivel.
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06-07-2013, 08:45 AM
RE: How I think of gravity!
So what does everyone think?
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06-07-2013, 10:23 AM
RE: How I think of gravity!
(06-07-2013 08:44 AM)UndercoverAtheist Wrote:  
(06-07-2013 06:51 AM)BryanS Wrote:  The mass doesn't really affect the distance of the pull. If you double the mass, to get the same amount of force before the doubling, you go square root of 2 times as far.

The density doesn't affect the force of the pull. If somehow you could instantaneously compress the earth to the size of a baseball, a person located where the surface of the earth used to be would experience the same gravitational force both before and after the compression of the earth. The only role density has is to allow you to get closer to the center of mass of an object that is more dense. So a black hole, which is a collapsed star that has become uber dense, can trap light that gets close enough. But no light will be trapped that passes outside the original spacial extent of the star.

All that aside, Einstein was in a league of his own. General relativity is an amazing theory that has made numerous incredible predictions, all of which have proven true. Since this is an atheist blog, I can't resist comparing the awesome discoveries of science to the burning bush revelations of the Bible and conclude religion comes up short.

What you said really isn't making any sense at all (aside from the mass affecting distance, you are correct when it comes to that).

I've studied black holes enough to know that the stars matter collapses in on itself to create an incredibly dense point, creating a singularity. The singularity is incredibly dense, and affects the amount of force it has once you get over the event horizon (so density affects force of gravity, eh?).

Also, think about a planet like Jupiter, not very dense, but massive. This mass allows it's gravitational field to reach out, grabbing space debris. At one point, jupiter might have acted like our sun did, grabbing space debris and colliding them within its gravitational lock. These space debris eventually became Jupiter's moons.

Now, if Jupiter had been a lot smaller, but with the same density, it would not have attracted those space debris and created moons for itself. Of course, it would have a few moons because of its density (it would have had a lot more force for its mass, so the same sized object that jupiter has could have been in orbit around the small jupiter, but not as many because the mass had decreased).

Oh, and your earth analogy is wrong. If you shrunk the earth down to the size of a baseball, a person located on it would be closer to the core, in turn making the force on his body over what we are experiencing now.

People all over the internet say that density does not affect gravity in any way.

Then I look at a star, and then I look at that star's black hole. Light can escape the star, light cannot escape a black hole. Meaning that the density of the object did affect the 3 dimensional plane of gravity in a way that light cannot even escape its tug.

"Think about the center of mass. The formula for universal gravitation has that r on the bottom. If the star becomes smaller but loses no mass, then things can get closer and have a much larger force applied on each other. Light can get closer to the center of mass and therefore would not escape this much larger force.

So in a way, this increase in density actually does affect gravity, but it's not the change in density that does it, it's the means by which it achieves this increased density that explains the increase in force." - Person on yahoo answers that explained it more eloquently than my insane drivel.


I think you misunderstood what I said about density. My example of the earth suddenly shrinking stated that the force on a person 'as if' they were where the surface of the earth was before it was compressed would be exactly the same.

To make it more clear, let us say you are about 6371km from the center of the earth (on the surface Smile ) . Now lets say you left the earth and while you were gone some evil alien with a big cosmic squeezer forced the earth into the volume the size of a baseball. Now, when you come back, you find that when you are 6371km away from where you thought the earth (you can't see it, it's too small) you find the exact same gravity force you found before you left earth. And the moon is orbiting in exactly the same orbit before you left. But now you can travel closer to the center of mass than before the earth was compressed. So if you move to within about a kilometer, you are 1/6371 the distance, and gravity will be about 40 million times as strong as when you were at the distance of where the surface used to be.


Density only affects gravity INSIDE the celestial object. This is simply due to the fact that when you are inside a massive object, the mass that is above you adds to gravitation that pulls you towards the surface and partially counteracts the gravitation force of the rest of the object that pulls you towards the center.

Here's a little picture I found showing that effect:
From http://en.wikipedia.org/wiki/Newton%27s_law_of_gravity
[Image: Earth-G-force.png]

But outside an object that is spherically symmetric, all that matters for determining the force of gravity is the total mass.
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06-07-2013, 10:35 AM
RE: How I think of gravity!
One other side point I should be clear on, yes, it is possible for the maximum force to be larger for a more dense object because you can get closer to the center of mass. That was in part my point about black holes and light not getting sucked in if it passes by a black hole, but not closer to it than the original extent of the star that was in place before the collapse. The gravitational field at the original star surface is the same as the gravitational field at the same point in space after the star has collapsed into a black hole (actually, it will be slightly less due to the mass lost in the collapse process)
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06-07-2013, 10:37 AM
RE: How I think of gravity!
(06-07-2013 10:23 AM)BryanS Wrote:  I think you misunderstood what I said about density. My example of the earth suddenly shrinking stated that the force on a person 'as if' they were where the surface of the earth was before it was compressed would be exactly the same.

To make it more clear, let us say you are about 6371km from the center of the earth (on the surface Smile ) . Now lets say you left the earth and while you were gone some evil alien with a big cosmic squeezer forced the earth into the volume the size of a baseball. Now, when you come back, you find that when you are 6371km away from where you thought the earth (you can't see it, it's too small) you find the exact same gravity force you found before you left earth. And the moon is orbiting in exactly the same orbit before you left. But now you can travel closer to the center of mass than before the earth was compressed. So if you move to within about a kilometer, you are 1/6371 the distance, and gravity will be about 40 million times as strong as when you were at the distance of where the surface used to be.

Density only affects gravity INSIDE the celestial object. This is simply due to the fact that when you are inside a massive object, the mass that is above you adds to gravitation that pulls you towards the surface and partially counteracts the gravitation force of the rest of the object that pulls you towards the center.

But outside an object that is spherically symmetric, all that matters for determining the force of gravity is the total mass.

Right! That's the beauty of conservative fields.

When you're outside the radius of the object generating the field, the shape, size, and density of that object are more or less irrelevant. Outside the stellar radius, a black hole has exactly the same gravitational pull as the star it used to be. There is the same amount of mass, and the same centre of mass, and the centre of mass is the same distance away.

The only thing that matters is the amount of field-generating stuff inside that radius. If it were a point source of the same strength, or if it were a perfect, uniformly distributed sphere, or if it's the irregular lump of matter the Earth is, doesn't matter. The strength of the field away from the source is the same.

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