Gravity and other fundamental forces

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Discussion Overview

The discussion revolves around the understanding of gravity compared to other fundamental forces, exploring the nature of gravity, its unique characteristics, and the challenges in reconciling it with quantum mechanics.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions what is not yet understood about gravity compared to the other fundamental forces, suggesting that gravity might simply be another force.
  • Another participant notes that gravitational force is unique in that it does not cause repulsion, implying a fundamental difference from the other forces.
  • A different viewpoint asserts that while gravity is well understood in certain contexts, it lacks a quantum description, which is a significant difference from the other fundamental forces.
  • This participant also discusses the implications of general relativity and the challenges of combining it with quantum mechanics, highlighting potential contradictions that arise when considering small black holes and energy conservation.
  • In contrast, another participant challenges the notion that the other fundamental forces are well understood, arguing that the causes of electromagnetic force remain unclear, similar to gravity.

Areas of Agreement / Disagreement

Participants express differing views on the understanding of gravity versus other fundamental forces, with no consensus reached on whether gravity is fundamentally different or if the other forces are equally unclear.

Contextual Notes

Participants highlight the lack of experimental support for a quantum description of gravity and the unresolved issues in combining general relativity with quantum mechanics, indicating limitations in current understanding.

rajeshmarndi
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What is it about gravity that is not yet understood unlike other fundamental forces.

Isn't gravity just another force like the other three fundamental forces.
 
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If i am not wrong thn Gravitational Force is the only force that does not cause repulsion...
 
Gravity is well understood in the contexts in which it has been measured so far, and is described using http://en.wikipedia.org/wiki/Introduction_to_general_relativity" . The difference between how gravity is understood and how the other three fundamental forces are understood is that unlike the other forces gravity does not have an experimentally supported quantum description.

General relativity says that the rest mass-energy of a system produces gravity, and that http://en.wikipedia.org/wiki/Black_hole_thermodynamics" constantly come into existence and then cease to exist over arbitrarily short time scales, so extremely small black holes would always be forming, but this would violate energy conservation since the black holes could not cease to exist as required by quantum mechanics. Thus, naively combining quantum mechanics and general relativity leads to contradictions. Since gravity is much weaker than the other forces in the situations in which its effects have been measurable there has been no way, so far, to determine what actually happens over the small length and/or short time scales at which corrections to general relativity (or quantum mechanics) become important.
 
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I'm wondering why you think that the "other fundamental forces" are well understood! We know no better what causes electromagnetic force than we do what causes gravity.
 

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