Do we move in the Universe? Or is everything stationary

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The discussion centers on the concept of movement within the universe, emphasizing that all motion is relative to other bodies of mass due to the absence of a definitive reference point. It argues that without a frame of reference, movement cannot be defined, leading to the conclusion that we cannot claim to "move" in the universe itself. The analogy of two astronauts illustrates that each perceives the other as moving, but neither can prove their motion without a third reference. This aligns with the principles of Special Relativity, which assert that motion is only meaningful when compared to another object. Ultimately, the conversation concludes that while we can track changes in distance relative to other masses, the notion of movement in the universe lacks a definitive measure.
  • #31
I was was not including the interference of gravity, but I like the discussion. I was more leaning towards the frame of reference of each body of mass to the universe.
 
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  • #32
Jaami M. said:
I was more leaning towards the frame of reference of each body of mass to the universe.

I think the point of the previous discussion is that there is no such thing in any absolute sense. We can construct reasonable definitions of what it means to be "moving with respect to the universe" (for example, vanhees71's suggestion that "moving" means "not seeing the CMBR as isotropic"), but no one of them can be singled out as "the" definition of what it means to be "moving". It all depends on your choice of coordinates and what problem you are trying to solve.
 
  • #33
Jaami M. said:
I was was not including the interference of gravity, but I like the discussion. I was more leaning towards the frame of reference of each body of mass to the universe.

Then in this context, the answers you got from previous posters are correct. My thought process only applies to your experiment where i take into account the gravity of the masses.

I was never against what PeterDonis was suggesting, he is writing in the context of reality. Which i agree is in the spirit of the forum. I just found the idea that i suggested interesting to think about.
 
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