GRT: Wrong Picture of Basic Cosmology?

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SUMMARY

The discussion centers on the misconceptions surrounding General Relativity Theory (GRT) and its implications for cosmology, particularly in relation to the expanding universe. The participant expresses confusion over the distinction between coordinates and physical distance, referencing a video by Leonard Susskind from Stanford University. Key points include the understanding that while the universe expands, the meter-scale remains constant and that the energy-momentum tensor contributes to the creation of new space rather than merely deforming existing space.

PREREQUISITES
  • Understanding of General Relativity Theory (GRT)
  • Familiarity with cosmological concepts, particularly the expanding universe
  • Knowledge of the energy-momentum tensor in physics
  • Basic grasp of coordinate systems in relativity
NEXT STEPS
  • Watch Leonard Susskind's video on cosmology for deeper insights
  • Study the implications of the energy-momentum tensor in General Relativity
  • Research the differences between spatial coordinates and physical distance in cosmology
  • Explore the concept of metric expansion of space in the context of an expanding universe
USEFUL FOR

Students of physics, cosmologists, and anyone interested in understanding the complexities of General Relativity and the nature of the expanding universe.

jensel
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Hello,

I hope you can help me. I thought I have an idea about GRT but I found this about about the basic cosmology. It is a link to a video from Stanford Univerisity. In short words: Susskind seems to confuse coordinates with distance. I can't understand that he seems to talk about defined coordinates and then about relativity. He seems to have a view that an expanding universe means that the meter-scale is involvolved.
If you have a sphere, for example, you will have a sphere. You will have physics which is locally not depending from the "geometry" given. A meter-scale is a meter-scale, there is no change in time.

I am confused.


 
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I can give myself a first answer. I have a bacic misunderstanding of GRT. Since the velocity of light is a constant the expansion of the universe is not bending the let's say meter-scale but a real expansion. An object real get's farer away from every point in the universe in the long scale terms. I find this really strange since it means that the energy-momentum tensor really creates new space, not just deforms it, right?
 

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