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Distance expansion and escape velocity ("thought experiment")
If you care to, it would help if you would check my arithmetic. I may have made one or more mistakes. Thanks to anyone who can show the conclusion here is wrong.
The question came up if you have a pair of kilogram masses and you place them each at CMB rest slightly over one light second apart, then does their Hubble law recession rate exceed their classic escape speed?
It is imagined that you do this out in "open" space, away from any galaxies, groups of galaxies, superclusters etc. So that even though the force of attraction between the pair of kilogram balls is unimaginably weak all the other forces can be neglected.
As time permits I will show some work indicating how I came by the answer, but for the moment to make a long story short, I found that the Hubble law expansion of 400,000,000 meters even though unimaginably slow does exceed the escape speed. So the two balls would continue to separate and not eventually start to fall towards each other.
That distance is roughly the distance from the Earth to the Moon.
If you care to, it would help if you would check my arithmetic. I may have made one or more mistakes. Thanks to anyone who can show the conclusion here is wrong.
The question came up if you have a pair of kilogram masses and you place them each at CMB rest slightly over one light second apart, then does their Hubble law recession rate exceed their classic escape speed?
It is imagined that you do this out in "open" space, away from any galaxies, groups of galaxies, superclusters etc. So that even though the force of attraction between the pair of kilogram balls is unimaginably weak all the other forces can be neglected.
As time permits I will show some work indicating how I came by the answer, but for the moment to make a long story short, I found that the Hubble law expansion of 400,000,000 meters even though unimaginably slow does exceed the escape speed. So the two balls would continue to separate and not eventually start to fall towards each other.
That distance is roughly the distance from the Earth to the Moon.
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