Why can't gravity be just a form of magnetic attraction?

Click For Summary

Discussion Overview

The discussion explores the idea of whether gravity could be understood as a form of magnetic attraction, examining theoretical parallels and differences between gravitational and electromagnetic forces. Participants delve into concepts from physics, including the photoelectric effect, inverse square laws, and the nature of gravitational and magnetic fields.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that the similarities in the mathematical form of Coulomb's law and Newton's law of gravitation might indicate a deeper connection, though they acknowledge significant differences in behavior and implications.
  • Others argue that gravitational forces are always attractive and independent of electric charge, contrasting with electromagnetic forces.
  • It is noted that gravitational fields behave differently than electromagnetic fields when sources are in motion, with references to concepts like "retarded potential."
  • Participants highlight that gravitational waves and electromagnetic waves are mathematically distinct, with gravitational waves having a different quadrupole moment.
  • One participant points out that magnetic fields lack monopole solutions, while gravitational sources are typically monopolar, which affects the nature of their fields.
  • There is a discussion about the breakdown of the inverse square law in strong gravitational fields, with references to specific phenomena like Mercury's anomalous precession.
  • Questions are raised regarding the conditions under which the inverse square law holds true for point-like sources and the implications of matter distribution.
  • A participant introduces the concept of 'twisted space' and teleparallel gravity, suggesting a potential avenue for further exploration.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the relationship between gravity and magnetic attraction, with no consensus reached on the validity of equating the two. Significant differences in the nature and behavior of gravitational and electromagnetic forces are acknowledged, but the discussion remains unresolved.

Contextual Notes

Limitations include the dependence on specific definitions of forces and fields, as well as unresolved mathematical considerations regarding the inverse square law in various contexts.

mamba76
Messages
4
Reaction score
1
Based on the photo electric effect. Maybe its perception that is the problem? Charge doesn't travel through a vaccuum. Electro magntic waves alway carry photons. Photons can make charge. Charge creates magnetism? Would explain why Coulumbs equation is the same as the one for gravity but on a much, much bigger scale.
 
  • Skeptical
Likes   Reactions: PeroK
Physics news on Phys.org
mamba76 said:
Based on the photo electric effect. Maybe its perception that is the problem? Charge doesn't travel through a vaccuum. Electro magntic waves alway carry photons. Photons can make charge. Charge creates magnetism? Would explain why Coulumbs equation is the same as the one for gravity but on a much, much bigger scale.
Although they both obey a similar-looking inverse square law in one particular case (nothing is moving) there are many differences:
- gravitational forces are always attractive and independent of the electric charge present.
- gravitational fields change differently than electromagnetic fields when the source is moving (Google for “retarded potential”).
- gravitational waves are mathematically different than electromagnetic waves (Google for “gravitational wave quadrupole moment”)
- gravity doesn’t really follow an inverse square law; the Newtonian ##1/r^2## is an approximation that breaks down in strong gravitational fields (Google for “Mercury anomalous precession”)

Probably some more, but this will do for a start
 
  • Like
  • Informative
Likes   Reactions: jsgruszynski, ohwilleke, Nik_2213 and 5 others
In addition to the correct points mentioned by @Nugatory one huge difference that is specific to magnetic fields instead of electric fields is that magnetic fields have no monopole solution, only a dipole solution at lowest order. The gravitational sources we observe around us are all approximately monopolar sources. A monopole source has a ##1/r^2## field, but a dipole source has a ##1/r^3## field. There is no way to get Kepler's law from dipoles.

Gravity is not a magnetic interaction. It has nothing to do with perception or the photo electric effect or anything else you mentioned.
 
  • Like
Likes   Reactions: ohwilleke, Nik_2213 and PeroK
Nugatory said:
Although they both obey a similar-looking inverse square law in one particular case (nothing is moving) there are many differences:
- gravitational forces are always attractive and independent of the electric charge present.
- gravitational fields change differently than electromagnetic fields when the source is moving (Google for “retarded potential”).
- gravitational waves are mathematically different than electromagnetic waves (Google for “gravitational wave quadrupole moment”)
- gravity doesn’t really follow an inverse square law; the Newtonian ##1/r^2## is an approximation that breaks down in strong gravitational fields (Google for “Mercury anomalous precession”)

Probably some more, but this will do for a start
Would the 1/r^2 thing never breakdown with point like sources? Is the distribution of matter what confounds it?
 
synthesizers said:
Would the 1/r^2 thing never breakdown with point like sources? Is the distribution of matter what confounds it?
The ##1/r^2## rule for electrical fields is exact as long as ##r## is non-zero, although we will have to use the integral form of that rule for the most charge distributions. In the special case of a spherically symmetric charge distribution (which includes point sources) the integral form reduces to the familiar Coulomb’s law.

The infinity that appears when we set ##r=0## is just telling us that that case is unphysical - the idealization of a point charge with a definite position breaks down at small distances so ##r## is no longer meaningful.
 
  • Haha
Likes   Reactions: mamba76
Update -- after a bit of cleanup this thread will remain closed. LOL
 
  • Like
Likes   Reactions: sophiecentaur and mamba76

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
6K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 29 ·
Replies
29
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 36 ·
2
Replies
36
Views
6K
  • · Replies 8 ·
Replies
8
Views
2K