Can a universe exist with no matter?

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Discussion Overview

The discussion centers around the concept of whether a universe can exist without matter, exploring theoretical implications and definitions of existence. Participants consider various aspects including the roles of space, time, and energy in relation to matter, as well as the philosophical implications of existence itself.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that if space, time, and energy are present, matter is inherently included.
  • Others propose that it is conceivable to imagine a state of existence with only energy, without the traditional constructs of time and space.
  • A participant suggests that the universe could eventually reach a state of "just radiation," particularly in the context of heat death and black hole dynamics.
  • One participant questions the definition of "exists," proposing that a mathematical model could exist without matter, but doubts its meaningfulness.
  • Another participant critiques the question as a tautology, asserting that mass and energy are interdependent, making the inquiry less meaningful.
  • Some argue that a universe can be defined with its own laws of physics, potentially allowing for a universe without matter.
  • A later reply discusses the philosophical aspect of existence, suggesting that without matter, a universe may not have observable impacts on our own universe.

Areas of Agreement / Disagreement

Participants express multiple competing views on the question, with no consensus reached regarding the possibility of a universe existing without matter. The discussion remains unresolved with various interpretations and implications presented.

Contextual Notes

Definitions of existence and the relationship between mass and energy are central to the discussion, with participants highlighting the complexity and potential tautological nature of the question posed.

Dremmer
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Just including space, time and energy, but no matter?
 
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energy is a kind of matter.
 
The answer is no.
 
i second answer no, because once you have space time and energy matter is a given.

but, i can easilly envision a kind of existence where there is no time, space or matter, but just energy.
 
Boy@n said:
i second answer no, because once you have space time and energy matter is a given.

but, i can easilly envision a kind of existence where there is no time, space or matter, but just energy.

Can you? Energy must act or move, which makes space necessary, and change in state means that time is necessary.
 
Dremmer said:
Just including space, time and energy, but no matter?

Given that the universe looks headed towards a heat death, then the answer seem yes.

Of course, there is the issue of the residual matter. Black holes might be able to sweep up and radiate away a lot of the remaining protons and electrons, but some would probably surely escape? And many more neutrinos.

But cosmologists like Charley Lineweaver seem comfortable with the idea of "just radiation" models where there is only the black body fizzle of photons between the event horizons of a de sitter spacetime.

The first moments of the big bang would also be matter-less? A relativistic plasma. Too hot for sub-light particles to actually "exist".
 
You need to define "exists."

If you mean create a mathematical model, then yes. If you mean make sense of it, then I doubt it.
 
Since mass and energy define each other the question is meaningless. Its a tautology similar to asserting that everything is made of "pure" energy (whatever that is!) You might as well ask how many angels can dance on the head of a pin for all the meaning we can glean from the question.
 
Well, you said "a" universe. A universe can have whatever laws of physics you give it. Therefore, a universe can exist without matter.
 
  • #10
This really gets back to the question of whether something has meaningful existence if it is not perceived or is not capable of being perceived. The only sense as humans in which we can say anything exists is relative to our perception of it (or our ability to infer its existence through our perception.) Therefore, the question breaks down to, can a universe without matter have any observable impact on our universe? I would tend to say no.
 

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