Massless Universe: Examining the Behaviour & Mass of Our Universe

  • Context: Graduate 
  • Thread starter Thread starter Xbehave
  • Start date Start date
  • Tags Tags
    Massless Universe
Click For Summary

Discussion Overview

The discussion explores the theoretical implications of a universe with a total mass of zero, examining both the behavior of such a universe and the potential existence of negative matter. Participants consider the consequences of massless scenarios in relation to general relativity and the nature of matter and antimatter.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question how a universe with a total mass of zero would behave and whether this can inform our understanding of the actual mass of our universe.
  • One participant suggests that a zero mass universe would lack gravitational interactions, rendering much of known physics irrelevant.
  • Another participant clarifies that they were referring to a universe with negative matter, prompting questions about the implications for general relativity.
  • Concerns are raised about the annihilation of matter and antimatter, suggesting that if negative matter were akin to antimatter, it could lead to a scenario where nothing remains.
  • There is a discussion about the nature of antimatter, with one participant asserting that antimatter has the same gravitational effects as regular matter, challenging the idea of negative matter as a counterpart.
  • A solution to general relativity for a massless universe, known as the Milne Model, is mentioned, although it is noted that this model does not involve antimatter.
  • Participants acknowledge the energy release that occurs when matter and antimatter annihilate, indicating a correction to earlier misconceptions.

Areas of Agreement / Disagreement

Participants express differing views on the nature of negative matter and its implications for gravitational interactions. There is no consensus on the existence or behavior of a massless universe, and the discussion remains unresolved regarding the implications of such a scenario.

Contextual Notes

Limitations include the dependence on definitions of matter and antimatter, as well as the unresolved nature of the implications of negative matter within the framework of general relativity.

Xbehave
Messages
6
Reaction score
0
How would a universe with a total mass of zero behave?
By comparing the expected result for a zero mass universe, can we be sure that our universe has total mass?
 
Space news on Phys.org
A universe with zero mass, if you mean a universe where the particles are masses would be dull. There would be no interaction due to gravity as it wouldn't exist. It would also take no energy to accelerate anything to any speed at any rate of acceleration. There are just simple effect so. Without mass lot, if not most, or the physics we know would be useless or not exist.
 
actually i meant a universe where we exist along side negative-matter, to give a total mass of zero, but i wondered if there was a solution for general relativity in this situation more than the physical implications of the fact there could be no matter in the universe.
 
this is a valid question, and is tied directly to "where is the anti-matter?"
 
Ahhhh, right ok, makes slightly more sense.

The only issue now is if you consider this negative-matter to be anti matter then at some point anti-matter and matter will eliminate each other leaving nothing...
 
anti-matter is electrically the opposite of normal matter, and it can be shown that any anti-matter that collided with its particle.
this negative matter would be the gravitational opposite of normal matter, I am not sure if it would be destroy on contact with its positive-particle. but as the same processes that form galaxies would push the negative-matter out it wouldn't be found inside galaxies, only between them (or visa-versa if a galaxy was formed by negative matter). Also as neg-mass-particles and normal ones always repel each other, it would take a very energetic event to cause a colision.

But my main question was if a solution to general relativity existed for a massless universe, and if this could describe our universe?
 
Anti-matter is not 'negative' matter. It still has the same gravitational effect as regular matter, i.e. it attracts and is attractive to all other matter (whether 'anti' or normal). The only way to get a zero mass universe is to have nothing in it at all.

Edit: There is a solution to GR for a massless Universe (in a way) that is known as the Milne Model. Google/Wiki that if you are interested. It has nothing to do with anti-matter though.
 
correct wallace...
and to be more correct, when matter and anti-matter annhilate they transform in radiation energy (photons)...

marco
 
I bow down to superior knowledge, thinking about it now there would be a release of energy...a substantial one too...my bad. I'm just a humble electronic engineer ;)
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 20 ·
Replies
20
Views
3K
  • · Replies 30 ·
2
Replies
30
Views
5K
  • · Replies 12 ·
Replies
12
Views
1K
Replies
18
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
1
Views
3K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 33 ·
2
Replies
33
Views
8K
  • · Replies 29 ·
Replies
29
Views
3K