What Is the Relationship Between Time and Space in the Universe?

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Discussion Overview

The discussion revolves around the relationship between time and space in the universe, exploring whether these concepts are physical entities or merely tools for human understanding. Participants engage with philosophical implications, the nature of information, and the interdependence of space and time, touching on theoretical frameworks like General Relativity (GR) and Quantum Field Theory (QFT).

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Philosophical

Main Points Raised

  • Some participants propose that time is a construct of human memory, while space exists independently of human perception.
  • Others argue that both space and time may be equally "real" or "unreal," suggesting a need for equal ontological status.
  • A participant questions whether space-time is a part of the universe or merely a descriptive tool, suggesting it could be both.
  • Concerns are raised about the definitions of space and time, with some suggesting that without particles, measuring space or time becomes problematic.
  • There is a discussion about the implications of General Relativity, particularly regarding vacuum solutions like DeSitter space, which challenge the notion of space-time as purely relational.
  • Some participants express skepticism about the philosophical nature of the discussion, advocating for a more mathematical approach to understanding these concepts.
  • One participant suggests that space serves as a link between objects, while time links events, proposing that time may not be a necessary physical entity.

Areas of Agreement / Disagreement

Participants do not reach a consensus, with multiple competing views on the nature of space and time, their relationship, and whether they are physical entities or constructs of human understanding.

Contextual Notes

Participants express varying degrees of confusion regarding the definitions and implications of space and time, indicating a reliance on philosophical interpretations that may not align with established scientific definitions.

  • #31
chill_factor said:
You can seriously see the wavefunction - the absolute square of it.
Sorry to say that, but that's a huge conceptual difference.

chill_factor said:
Lets take the graviton instead. To distinguish a graviton signal from a neutrino signal would require shielding that would collapse into a black hole. Therefore the graviton is not observable in principle. http://arxiv.org/abs/gr-qc/0601043
I am sorry but as long as there is no reliable theory of quantum gravity which explains what the "mathematical entity graviton" means we cannot safely say whether a "graviton as physical entity" does exist. In addition it may very well be that the final theory of quantum gravity does not even contain a graviton as fundamental d.o.f., therefore it could be that it does neither exist mathematically nor physically and that there is no such problem at all.

chill_factor said:
How many things are simply not observable because their detection or creation has unphysical requirements or even physically impossible requirements?
A lot - but why should we care? OK, you may complain about the fact that a specific theory (which one?) contains too many unphysical entities and that (according to Ockhams razor) it should be replaced by something which is less wasteful ontologically. Of course you are invited to develop such a theory (what do you have in mind?).
 
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  • #32
chill_factor - What about a photon moving at c, it's not observable between events. What do you make of this stuff that separates events?
 
  • #33
chill_factor said:
I believe it does. I'd say science is not a subset of philosophy that deals with empirical things; it is a subset of engineering that deals with fundamental limits instead of practical limits.

I think you should review what engineering and science are. Here are a couple of links.
http://en.wikipedia.org/wiki/Engineering
http://en.wikipedia.org/wiki/Science

As such, the physicality (observability) of the systems we deal with is important. At the end of the day science is not philosophy because science is about data.

Here's a link to philosophy. And on the philosophy of science.
http://en.wikipedia.org/wiki/Philosophy
http://en.wikipedia.org/wiki/Philosophy_of_science


Just read some arXiv high energy, cosmology, etc. papers and tell me with a straight face that if those disappeared tomorrow, the world would be a worse place.

It would be, for we would not know what paths have already been taken.
 

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