Does mass exist when matter is completely inert?

  • Context: Graduate 
  • Thread starter Thread starter _233\/3
  • Start date Start date
  • Tags Tags
    Mass Matter
Click For Summary

Discussion Overview

The discussion revolves around the concept of mass in relation to particles that are considered completely inert, specifically questioning whether mass exists when there is no motion. Participants explore theoretical implications, particularly in the context of cosmological models and fundamental physics principles.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions if it is meaningful to discuss the physics of particles that are completely inert, suggesting that all measured particles are always in some state of motion.
  • Another participant argues that even at absolute zero, fermions possess non-zero Fermi energy, implying they retain mass despite having no translational motion.
  • Some participants reference Roger Penrose's conformal cyclic cosmology, debating whether mass could decay or if all motion ceases at heat death, leading to a potential absence of mass.
  • Concerns are raised about gravitational potential energy in isolated systems, questioning if it exists without interactions with other particles.
  • One participant emphasizes that mass is invariant across reference frames, asserting that objects have mass regardless of their state of motion.
  • Another participant challenges claims made without supporting physics, asking for citations to back up assertions regarding heat death and mass.

Areas of Agreement / Disagreement

Participants express multiple competing views on the nature of mass and its relationship to motion, with no consensus reached on the implications of complete inertia or the effects of heat death on mass.

Contextual Notes

Discussions involve assumptions about the nature of motion, reference frames, and the definitions of mass and energy, which remain unresolved and may depend on specific interpretations of physical theories.

_233\/3
Messages
5
Reaction score
0
I've been thinking about mass and the question occurred to me: If a particle is completely inert i.e. absolutely no motion whatsoever then does it still have a mass? I ask because, as far as I understand it, everything we've ever measured cannot strictly be said to be inert. That is: Every particle we've measured is always under some kind of motion.

Thanks, :)
 
Physics news on Phys.org
If you are talking about the physics of a situation that is, in your mind, impossible even in principle, then is it really physics? In other words, if you consider every particle ever measured to be in motion then it seems that you believe that being at rest is impossible, so how can you answer questions about impossible states?

In all possible states tested so far massive particles do not lose their mass due to moving slowly.
 
You can wait until God knows when all heat (particle motion) energy is over in the universe and you will still have the gravitational potential energy that is a property of something that has MASS.
Every time your car stops , it doesn't disappear in thin air does it?
Well , why do you think black holes form? Well yes even after supernova the particles making up stars are still in some motion but even if they would suddenly loose all their motion a black hole would still form.
 
What happens (theoretically) to a system of identical fermions (which cannot occupy the same quantum state) at absolute zero? The system still has non-zero Fermi energy. Doesn't this imply fermions still have mass at 0 K (no translational motion)?
 
Last edited:
I was thinking specifically in terms of Roger Penrose's conformal cyclic cosmology. In his hypothesis mass is required to eventually decay over time. I wondered whether it is plausible that instead of mass decaying, all motion stops at the heat death and then there is no more mass.
 
_233\/3 said:
I was thinking specifically in terms of Roger Penrose's conformal cyclic cosmology. In his hypothesis mass is required to eventually decay over time. I wondered whether it is plausible that instead of mass decaying, all motion stops at the heat death and then there is no more mass.

How does heat death equate to no mass? No thermal energy is not the same as no mass.

Zz.
 
Penrose's CCC is a solution in GR, and in GR the stress-energy tensor follows a well-known continuity equation which ensures that mass/energy etc. cannot simply disappear.
 
Crazymechanic said:
You can wait until God knows when all heat (particle motion) energy is over in the universe and you will still have the gravitational potential energy that is a property of something that has MASS.
Every time your car stops , it doesn't disappear in thin air does it?
Well , why do you think black holes form? Well yes even after supernova the particles making up stars are still in some motion but even if they would suddenly loose all their motion a black hole would still form.

Do particles still have gravitational potential energy if they are trapped in their own light cones; isolated from everything else (eg. when space has sufficiently expanded)? Surely GPE only exists when a particle is in relation to other particles...?
 
gravity is a property of mass , any kind and any size. particles including.Just like the need to sleep is a property of humans any color, size or shape.

Now as long as physics knows , there is no know way to stop gravity or shield it.You can shield Em radiation and photons etc but you cannot shield gravity.
No matter how many particles would there be left in space even if one it still would have a gravitational potential to it.
The strength of gravity falls of with distance and obeys the inverse square law.

http://en.wikipedia.org/wiki/Inverse-square_law

And no a lightcone cannot stop gravity , indeed light itself is influenced by it.Photons to be exact curve around strong gravitational fields and when the fields get extremely strong photons "fall into them" Hence Black holes.
 
  • #10
"absolutely no motion whatsoever" in which reference frame?
For every particle, at every moment in time, there are reference frames where it is at rest, and others where it is not. Do objects have mass? Sure. Mass is invariant under coordinate transformations, so it is the same in all reference frames.
 
  • #11
_233\/3 said:
Do particles still have gravitational potential energy if they are trapped in their own light cones; isolated from everything else (eg. when space has sufficiently expanded)? Surely GPE only exists when a particle is in relation to other particles...?

I'm still waiting for you to show what physics that we know of today actually support any of what you have posted here. You seem to throw out a lot of claims, but you didn't actually support those with any established physics.

So, can you at least cite a paper that equate heat death with no mass? Can we at least settle things one at a time before bringing up something else?

Zz.
 
  • #12
Thread closed pending moderation.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 190 ·
7
Replies
190
Views
17K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 40 ·
2
Replies
40
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 18 ·
Replies
18
Views
4K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 35 ·
2
Replies
35
Views
4K