Item — HN Reader

The expansion of the Universe is irrelevant in this case. Our galaxy is gravitationally bound, so things (stars, planets, etc) within it do not follow Hubble's law. So there will be no modification to Voyager's distance from earth as a result of the Universe's expansion.

Even nearby galaxies don't obey Hubble's law. Andromeda, for example, is moving towards us, despite the overall expansion of the universe. In this case, it is due to the gravitational attraction between it and our galaxy.

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You are offering a more sophisticated take on the matter. At non-cosmological scales, metric expansion (i.e., the Hubble law) is not occurring because of bulk gravitational attraction.

The arithmetic I did is a tool illustrating the scale that is needed to make metric expansion operative. The arithmetic has the advantage of giving a quantitative idea how far away Earth-Voyager is from the necessary scale.

> The arithmetic I did is a tool illustrating the scale that is needed to make metric expansion operative.

You might revisit the wording then. As it's written it implies that with arbitrarily increased measurement precision, we could measure an effect of the Hubble Flow on Voyager's movement. But even with arbitrary precision we'd never measure an effect from the Hubble Flow on Voyager's motion because the expansion of the Universe isn't contributing to the relative motion between Earth and Voyager.