GRT: Wrong Picture of Basic Cosmology?

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The discussion revolves around the confusion regarding General Relativity Theory (GRT) and its implications for cosmology, particularly in relation to the expanding universe. The participant expresses difficulty in understanding how coordinate systems relate to physical distances and the implications of an expanding universe on the meter-scale. They highlight a perceived misunderstanding of GRT, noting that while the speed of light is constant, the universe's expansion suggests that objects are genuinely moving away from each other, creating new space rather than merely deforming existing space. This raises questions about the nature of the energy-momentum tensor in relation to space expansion. The participant seeks clarity on these concepts to reconcile their understanding of GRT with cosmological principles.
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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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