What in the world does E =mc2 mean?

  • Context: High School 
  • Thread starter Thread starter Matthias765
  • Start date Start date
  • Tags Tags
    Mean
Click For Summary

Discussion Overview

The discussion revolves around the meaning and implications of Einstein's equation E=mc², exploring its theoretical foundations, interpretations, and applications in various contexts, including thermodynamics and particle physics.

Discussion Character

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

Main Points Raised

  • Some participants propose that E=mc² indicates that energy can be obtained from mass through a conversion factor of c-squared.
  • There is a discussion about the nature of energy, with some suggesting it refers specifically to the energy of photons, while others argue that energy can take many forms.
  • One participant asserts that heating a pot of water increases its mass, while another challenges this claim, leading to a debate about the definition of mass and its relation to energy.
  • Some participants discuss the concept of relativistic mass and how it may change with temperature, while others maintain that mass is invariant and only kinetic energy changes.
  • There are references to different definitions of mass, including invariant mass and relativistic mass, and how these definitions impact the understanding of energy and momentum.
  • One participant mentions a webpage that discusses the relationship between mass and velocity, prompting questions about the validity of the claims made.

Areas of Agreement / Disagreement

Participants express differing views on the implications of E=mc², particularly regarding the relationship between mass and energy, the effects of temperature on mass, and the definitions of mass. No consensus is reached, and multiple competing views remain throughout the discussion.

Contextual Notes

The discussion includes various assumptions about the definitions of mass and energy, as well as the conditions under which certain claims hold true. Some arguments depend on specific interpretations of relativistic physics, which may not be universally accepted.

  • #31
Aer said:
You are reiterating the concepts since abandoned by physicists. I am very aware that Einstein proposed relativistic mass long ago.
You asked for a reference; I provided one. No need to be so harsh.

Aer said:
And it is this situation (measuring acceleration in a single inertial reference frame) in which relativistic mass has any relevance.
You seem to be assuming that the only thing we care about is how the world looks to us as we accelerate. But what about how things look to us as we accelerate them, while we remain inertial? For instance, when we get particles moving close to the speed of light in particle accelerators, the concept of relativistic mass does have use to us then because we do have a single inertial reference frame with which to make the measurement. Why can't we put a charged particle in a strong enough magnetic field to accelerate it faster than the speed of light? A very simple explanation is that its relativistic mass increases as we accelerate it, so its inertia/resistance to acceleration increases as well.
 
Physics news on Phys.org
  • #32
εllipse said:
You asked for a reference; I provided one. No need to be so harsh.

You seem to be assuming that the only thing we care about is how the world looks to us as we accelerate. But what about how things look to us as we accelerate them, while we remain inertial? For instance, when we get particles moving close to the speed of light in particle accelerators, the concept of relativistic mass does have use to us then because we do have a single inertial reference frame with which to make the measurement. Why can't we put a charged particle in a strong enough magnetic field to accelerate it faster than the speed of light? A very simple explanation is that its relativistic mass increases as we accelerate it, so its inertia/resistance to acceleration increases as well.
I've never said you cannot do this to obtain a correct result. However, it is not necessary to use relativistic mass to get the same thing, that is all I am saying. Relativistic mass is mearly a perception in other frames - however, too many people equate this perception to be actual mass accumulation to the object in the objects rest frame. This point of view is very wrong. It is just as easy to not use relativistic mass, but I'm not going to prohibit you from doing so.
 
  • #33
pmb_phy said:
Then as the gas is heated the particles move faster. The faster they move the greater the weight.
What is the weight of a particle (you may choose any particle you wish) moving .9999c through the atmosphere?
 

Similar threads

  • · Replies 67 ·
3
Replies
67
Views
8K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 5 ·
Replies
5
Views
6K
  • · Replies 63 ·
3
Replies
63
Views
8K
  • · Replies 7 ·
Replies
7
Views
3K