Space + time = space time? then....

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SUMMARY

The discussion centers on the relationship between the accelerating expansion of space and the concept of time within the framework of Einstein's theory of relativity. Participants argue that while space is expanding at an accelerating rate, this does not imply that time itself is accelerating. The FLRW (Friedmann-Lemaître-Robertson-Walker) metric is referenced, emphasizing that time and space are distinct dimensions within a geometric framework. The conversation also touches on the implications for cosmic models, such as Guth's inflation theory, and the measurement of time dilation through redshift as one looks back toward the Big Bang.

PREREQUISITES
  • Understanding of Einstein's theory of relativity
  • Familiarity with the FLRW metric in cosmology
  • Knowledge of cosmic expansion and redshift phenomena
  • Basic grasp of time dilation concepts
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  • Research the FLRW metric and its implications for cosmology
  • Explore the concept of redshift and its role in measuring cosmic distances
  • Study the principles of time dilation in the context of general relativity
  • Investigate Guth's inflation theory and its relationship to cosmic expansion
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Astronomers, physicists, and students of cosmology seeking to deepen their understanding of the relationship between space and time in the context of the expanding universe.

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probably a daft question asked before. but. if space is expanding at an accelerating rate would that mean time is accelerating too?
probably a daft question asked before, but.

if space is expanding at an accelerating rate would that mean time is accelerating too?.
after all Einstein* claims and the maths seems to say that space and time are the same thing, ie space-time.
so if space is expanding faster and faster shouldn't that mean time is also?.
and as a result in the past time passed slower?.

would this also mean that the speed of light is only constant relative to the space time its traveling through?.

if this is true would it negate guths inflation model?

if not please feel free to pontificate, postulate and reason ;)

*edit
 
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Time is expanding. We call it the future.
 
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yes its expanding. but at an accelerating rate?.
 
HEXiT said:
yes its expanding. but at an accelerating rate?.

The expansion of space means that distances between points increases over time. The rate at which this expansion is happening is increasing over time, which we call accelerating expansion. Accelerating time doesn't have any meaning that I can see.
 
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HEXiT said:
so if space is expanding faster and faster shouldn't that mean time is also?

I don't know what this means. I suspect you don't either. Can you describe how such a thing would be measured?
 
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yes but we measure time over a given distance via the speed of light, but that distance is always getting bigger due to expansion.
 
HEXiT said:
Ernestine
Is that Albert's sister?
HEXiT said:
if space is expanding at an accelerating rate would that mean time is accelerating too?.
No. I'm not sure "time accelerating" really makes sense. The FLRW solution includes the scale factor of space changing as a function of time, but it doesn't affect its notion of time.
 
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HEXiT said:
Summary:: probably a daft question asked before. but. if space is expanding at an accelerating rate would that mean time is accelerating too?

Einstein* claims and the maths seems to say that space and time are the same thing, ie space-time.
so if space is expanding faster and faster shouldn't that mean time is also?.
It may not be immediately obvious from your exposure to relativity, but it is a very geometric theory. Time and space aren’t the same thing, they are different directions in the same space.

The idea that space is expanding means that the universe is shaped like a trumpet. It has a small end and a big end. Saying that the trumpet expands as you go along the trumpet doesn’t mean that the length changes, it just means that the shape is not a cylinder but something more interesting.
 
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If you were to look back in time towards the big bang, wouldn't you measure time dilation?
 
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Andrew Wright said:
If you were to look back in time towards the big bang, wouldn't you measure time dilation?
Yes, but in cosmology they call it redshift
 

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