Faster than Light: Mystery of Sun & Big Bang

  • Context: Graduate 
  • Thread starter Thread starter Trave11er
  • Start date Start date
  • Tags Tags
    Light
Click For Summary

Discussion Overview

The discussion centers around the application of the Boltzmann formula in calculating particle speeds, particularly in extreme conditions such as the core of the Sun and during the Big Bang. It explores theoretical implications and the validity of using classical mechanics in relativistic contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that using the Boltzmann formula for calculating speeds at high temperatures yields values exceeding the speed of light for electrons in the Sun's core and nucleons after the Big Bang.
  • Another participant corrects the temperature of the Sun, stating it is significantly cooler than initially suggested.
  • There is a discussion about the inapplicability of the classical kinetic energy formula (KE = 1/2mv²) in relativistic scenarios.
  • A question is raised regarding the potential use of the Boltzmann formula to estimate speeds when relativistic effects are considered, with some uncertainty about its accuracy in such cases.
  • A later reply mentions that the speed distribution for relativistic particles is described by the Maxwell-Juttner distribution, which is more complex than the Maxwell-Boltzmann distribution.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of the Boltzmann formula in relativistic contexts, and there is no consensus on the accuracy of estimates derived from it.

Contextual Notes

The discussion highlights limitations related to the assumptions made in applying classical formulas to relativistic conditions and the need for a more complex distribution model for relativistic particles.

Trave11er
Messages
71
Reaction score
0
Hi everyone!

If Boltzmann formula is used to find speed then it gives values bigger than speed of light for electrons at the core of Sun (T=15,7*10^9 K) and for nucleons at the moment of their formation after the Big-Bang (T is bigger than 10^12 K). Why?
 
Physics news on Phys.org
The sun is 1000 times cooler than that.
 
Vanadium 50 said:
The sun is 1000 times cooler than that.

Oops, yeah, you are right. But what about the second part?
 
You can't use KE = 1/2mv2 when speeds are relativistic.
 
Doc Al said:
You can't use KE = 1/2mv2 when speeds are relativistic.

All right. But if we take relativistic effects into account can we still use Boltzmann formula to estimate speeds in such cases?
 
Trave11er said:
But if we take relativistic effects into account can we still use Boltzmann formula to estimate speeds in such cases?
That's a good question. I suspect you can use it to get an estimate, but I don't know how good it would be. The distribution of speeds for relativistic particles is governed by the Maxwell-Juttner distribution, which is more complicated that the Maxwell-Boltzmann distribution. (I've long since forgotten how that's derived. :frown:)
 
Ok. Thanks a lot.
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 26 ·
Replies
26
Views
4K
  • · Replies 40 ·
2
Replies
40
Views
5K
  • · Replies 24 ·
Replies
24
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
10K
  • · Replies 27 ·
Replies
27
Views
4K
  • · Replies 4 ·
Replies
4
Views
5K