Explaining the Grand Design: Time & Change without Time

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SUMMARY

The discussion centers on the interpretation of time and change during the early inflationary period of the universe as described in "The Grand Design." Participants argue that without a time dimension, change cannot occur, contradicting the notion of inflation as a change. They clarify that change can occur with respect to both time (d/dt) and space (d/dx), emphasizing that physical theories like Maxwell's equations involve spatial changes. The conversation critiques the simplifications found in popular science literature and stresses the importance of mathematical physics in understanding these concepts.

PREREQUISITES
  • Understanding of inflationary cosmology
  • Familiarity with mathematical physics and derivatives (d/dt and d/dx)
  • Knowledge of Maxwell's equations and their implications
  • Basic concepts of spacetime and energy conservation
NEXT STEPS
  • Research the implications of inflationary cosmology on the nature of time
  • Study the mathematical foundations of Maxwell's equations
  • Explore the continuity equation in physics and its relation to conservation laws
  • Investigate the transition from spacelike to timelike dimensions in cosmological models
USEFUL FOR

Physicists, cosmologists, and students of theoretical physics seeking a deeper understanding of the relationship between time, change, and the mathematical frameworks that describe the universe's evolution.

  • #31
It seems like pretty typical pop-sci language. Very flowery and sweeping, but also quite vague. It might be that he is describing the possible breakdown of the manifold structure at small scales, but it is too vague to know for sure. If I were you I wouldn't waste any more time trying to puzzle it out, you would be better off watching the Susskind lectures on GR or reading Sean Carrolls lecture notes or even reading Wikipedia entries.

None of the other references I have read on GR have mentioned how/why time should behave like a spatial dimension when the universe was small. Are you recommending these sources because they specifically deal with this issue, or because they are just good resources for GR in general?

There are some places in his book where he clarifies to say "not everyone agrees with me here.." but on these subjects, he is very matter of fact and states them as if its simply common knowledge among physicists. Is Hawking the only one who has these beliefs?
 
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  • #32
junglebeast said:
None of the other references I have read on GR have mentioned how/why time should behave like a spatial dimension when the universe was small. Are you recommending these sources because they specifically deal with this issue, or because they are just good resources for GR in general?
The references I recommended are just good references in general, and much clearer than this one. Nothing I have read mentioned this either, which is primarily the reason I wouldn't waste my time on it.

junglebeast said:
There are some places in his book where he clarifies to say "not everyone agrees with me here.." but on these subjects, he is very matter of fact and states them as if its simply common knowledge among physicists. Is Hawking the only one who has these beliefs?
Unfortunately, the wording is so vague that I can't even tell what the beliefs are, let alone whether other physicists agree.
 

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