Relativistic Mass-Energy: Charge & Particles

  • Context: High School 
  • Thread starter Thread starter 1977ub
  • Start date Start date
  • Tags Tags
    Charge Relativistic
Click For Summary

Discussion Overview

The discussion revolves around the relationship between charge and relativistic mass-energy, specifically whether the presence of charge contributes to relativistic mass-energy and if interactions between charged particles are necessary to generate charge-related mass-energy. The scope includes theoretical considerations and mathematical formulations related to charged black holes.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the presence of charge does add to relativistic mass-energy due to the associated electromagnetic field and its stress-energy.
  • Others argue that it is not necessary for two particles to interact (attract or repel) to generate charge-related mass-energy.
  • A participant references the Reissner–Nordström metric to illustrate how charge affects the gravitational field of a charged black hole, providing mathematical expressions for gravitational acceleration in both charged and uncharged states.
  • Further details are provided regarding the relationship between irreducible mass and charge in black holes, including equations that describe changes in gravitational fields when charge is considered or removed.

Areas of Agreement / Disagreement

Participants express differing views on whether charge contributes to relativistic mass-energy and the necessity of particle interactions for this contribution. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

The discussion includes complex mathematical relationships and assumptions regarding the definitions of mass and charge in the context of general relativity, particularly concerning black holes. There are unresolved aspects regarding the implications of these equations and the realism of charged black holes.

1977ub
Messages
530
Reaction score
22
Does The Presence of Charge Add To Relativistic Mass-Energy, or does it take two particles attracting or repelling one another to generate charge-related mass-energy?
 
Physics news on Phys.org
1977ub said:
Does The Presence of Charge Add To Relativistic Mass-Energy,

Yes. The presence of charge means there is an electromagnetic field, and the electromagnetic field has stress-energy.

1977ub said:
does it take two particles attracting or repelling one another to generate charge-related mass-energy?

No.
 
  • Like
Likes   Reactions: 1977ub
1977ub said:
Does The Presence of Charge Add To Relativistic Mass-Energy, or does it take two particles attracting or repelling one another to generate charge-related mass-energy?

While PeterDonis has answered the question, you can see this at work in the Reissner–Nordström metric which is the vacuum solution for a charged black hole. Gravity for a charged black hole is-

a_g=\frac{M}{r^2\sqrt{1-\frac{2M}{r}-\frac{Q^2}{r^2}}}

where M=Gm/c^2 (mass in geometric units) and Q=C\sqrt(Gk_e)/c^2 (charge in geometric units) where G is the gravitational constant, c is the speed of light, C is the charge in Coulombs and k_e is Coulomb's constant (as a rule, M\geq Q). Multiply the answer by c^2 for S.I. units of gravity (m/s2).

If charge is removed and the black hole is reduced to it's irreducible mass (the same black hole becoming a Schwarzschild black hole) where-

M_{\text{ir}}=\frac{r_+}{2}\ \ \rightarrow\ \ M=\frac{Q^2}{4M_{\text{ir}}}+M_{\text{ir}}

where M_{\text{ir}} is the irreducible mass and r_+=M+\sqrt{M^2-Q^2} is the outer event horizon, the equation for gravity becomes-

a_g=\frac{M{\text{ir}}}{r^2\sqrt{1-\frac{2M{\text{ir}}}{r}}}

you'll notice a distinct drop in the gravity field at a specific r some distance from the black hole. It might also be worth looking at Kerr-Newman metric which also includes for spin. Up to 50% of RN black hole's 'mass' can be attributed to charge though charged black holes are not considered realistic.

More info-
https://www.physicsforums.com/threads/what-is-irreducible-mass.762993/
 
  • Like
Likes   Reactions: 1977ub

Similar threads

  • · Replies 102 ·
4
Replies
102
Views
7K
Replies
9
Views
2K
  • · Replies 55 ·
2
Replies
55
Views
6K
Replies
3
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 20 ·
Replies
20
Views
3K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 45 ·
2
Replies
45
Views
5K
  • · Replies 25 ·
Replies
25
Views
3K