How Does Gravity Work From Earth's Core to the Universe's Edge?

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Discussion Overview

The discussion revolves around the nature of gravity, particularly how it operates from the Earth's core to the broader universe. Participants explore theoretical aspects of gravity, including the role of mass, the concept of gravitons, and the implications of general relativity. The conversation includes questions about the experience of gravity inside the Earth and the effects of gravitational forces at different depths.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question the origin of gravity, particularly whether gravitons are necessary for the standard model and what produces them.
  • There is a discussion about the concept of gravity being strongest at the center of the Earth, with some clarification that this depends on how "strength" is defined.
  • One participant explains that inside the Earth, gravity pulls in all directions, leading to no net force at the very center, despite the experience of time dilation.
  • Another participant notes that gravity is not confined to large celestial bodies, asserting that all objects with mass create a gravitational curvature in spacetime.
  • There is an emphasis on distinguishing between gravitational potential and gravitational force when discussing gravity's behavior inside a spherical mass.

Areas of Agreement / Disagreement

Participants express various viewpoints on the nature of gravity, with no clear consensus reached. Some concepts are clarified, but fundamental questions about gravity's origin and behavior remain contested.

Contextual Notes

Participants acknowledge the complexity of integrating quantum mechanics with general relativity, particularly regarding the concept of gravitons. There are also distinctions made between gravitational potential and force that are not fully resolved.

fellupahill
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Thanks for darrackth(or whatever his username is. I am on my phone so its hard to look) for the quote that got me thinking

The core of the Earth is at it's center. The gravity does not start there, as all of Earths matter contributes to gravity, not just the center. And yes, we would be crushed. There have been wells and tunnels drilled thousands of feet deep where we can measure the increasing pressure of the above rock and earth. There is no reason to think this simply stops happening at the core.

Where does the gravity come from tho? If gravitons exist(Do they have to for the standard model to work?) then what produces the gravitons? All the matter? or just the matter on the edge of the solid mass object? Why is the gravity strongest at the center? If gravity is pulling matter and energy twords itself how does gravity work "inside" the planet. If we carved a room out of the Earth near the core and found a way to get down inside, what would the gravity be like in that room? Is the force still pulling twords the center? And what's at the very centerpoint of gravity ?
I know that was a lot of questions, and I don't expect someone to answer them all individually. It would be awesome if someone could take my post, see how I am looking at gravity and provide some insight to clarify the things I need clarifying on :)
 
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fellupahill said:
Where does the gravity come from tho? If gravitons exist(Do they have to for the standard model to work?) then what produces the gravitons? All the matter? or just the matter on the edge of the solid mass object?

Gravity is extremely well described by Einstein's Theory of General Relativity. According to GR mass and energy both warp or bend spacetime, which manifests itself to us as the force of gravity. If you are searching for a "why" beyond this then science cannot help you, as there is nothing else that accurately describes gravity.

Why is the gravity strongest at the center?

This highly depends on what you mean by saying "strongest". The greatest concentration of mass is at the Earths core, so on a volume basis it would have the most gravity. HOWEVER...

If gravity is pulling matter and energy twords itself how does gravity work "inside" the planet. If we carved a room out of the Earth near the core and found a way to get down inside, what would the gravity be like in that room? Is the force still pulling twords the center? And what's at the very centerpoint of gravity ?

...inside the Earth you have gravity pulling you in all directions. If you are in the very middle of the core you still experience time dilation but you do NOT feel a NET force in any direction because the Earth is pulling you equally in all directions. Note that this is not saying you don't feel any gravity, as you still experience time dilation, it's just that the force of gravity is equal in every direction, leading to no net pull.
 
fellupahill said:
Thanks for darrackth(or whatever his username is. I am on my phone so its hard to look) for the quote that got me thinking



Where does the gravity come from tho? If gravitons exist(Do they have to for the standard model to work?) then what produces the gravitons? All the matter? or just the matter on the edge of the solid mass object? Why is the gravity strongest at the center? If gravity is pulling matter and energy twords itself how does gravity work "inside" the planet. If we carved a room out of the Earth near the core and found a way to get down inside, what would the gravity be like in that room? Is the force still pulling twords the center? And what's at the very centerpoint of gravity ?
I know that was a lot of questions, and I don't expect someone to answer them all individually. It would be awesome if someone could take my post, see how I am looking at gravity and provide some insight to clarify the things I need clarifying on :)

Gravitons are currently just a vague idea, as at present there is no theory which includes both quantum mechanics and general relativity.

When you refer to the "strength" of gravity, you need to distinguish between the gravitational potential (loosely, how "deep" it is) and the acceleration or force (loosely, how "steeply sloping" it is).

In both Newtonian gravity and in general relativity, there is no gravitational force inside a spherically symmetrical hollow. It's at a lower potential than outside, but there's no "slope".
 
Im doing a halfway terrible job of explaining myself. I am gunna think about it abit more then get back to you with a rephrasing.

"inside the Earth you have gravity pulling you in all directions. If you are in the very middle of the core you still experience time dilation but you do NOT feel a NET force in any direction because the Earth is pulling you equally in all directions. Note that this is not saying you don't feel any gravity, as you still experience time dilation, it's just that the force of gravity is equal in every direction, leading to no net pull." Very informative.
 
fellupahill said:
Im doing a halfway terrible job of explaining myself. I am gunna think about it abit more then get back to you with a rephrasing.

"inside the Earth you have gravity pulling you in all directions. If you are in the very middle of the core you still experience time dilation but you do NOT feel a NET force in any direction because the Earth is pulling you equally in all directions. Note that this is not saying you don't feel any gravity, as you still experience time dilation, it's just that the force of gravity is equal in every direction, leading to no net pull." Very informative.

Yes just remember gravity is not confined to planets/suns. All objects with mass have a gravitational curvature on spacetime. The Sun, Earth and Moon are our most obvious examples of spacetime curvature, while gravity is the weakest fundamental force it can also dominate such as in the Solar system. Remember though that even the pen on my desk curves spacetime and therefore has a gravitational "force" - it is just much less than the Earth because it is not as massive.

Hope this helps.
 

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