Sitting on a (very) extended object in space

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SUMMARY

The discussion centers on the behavior of a long rigid rod in space, specifically its center of mass in relation to the Hubble flow. It is established that the center of mass remains at rest with respect to the Hubble flow. When traveling to one end of the rod, an observer will perceive nearby objects moving parallel to the rod at a velocity of v = H_0 L/2, where H_0 represents the Hubble constant. Additionally, the conversation highlights the possibility of achieving a zero Hubble redshift by accelerating, allowing the observer to move relative to surrounding objects.

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johne1618
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Hi,

I imagine a very long rigid rod in space with length L.

I assume that the center of mass of the rod will be at rest with respect to the Hubble flow - is that right?

If I travel to one of the ends of the rod will I now see nearby objects that are moving with the Hubble flow move past me parallel to the rod with a velocity v = H_0 L/2 where H_0 is the Hubble constant?

John
 
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You can also do this by accelerating so the Hubble red-shift for some distant object is zero. Then it comes as no surprise that you are moving with respect to the objects around you.
 

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