On: Astronomers posit that we live in an area with bel...

[mxkopy]

> That is because the average matter distribution in the universe is the same in all directions from us, so the "gravity" from it cancels out.

Can't gravity have an infinitesimally small effect, which means this matter distribution has to be perfectly balanced for its gravity to cancel out to zero at some point?

[pdonis → mxkopy]

> this matter distribution has to be perfectly balanced for its gravity to cancel out to zero at some point?

In principle, there are of course effects due to the matter distribution not being perfectly spherically symmetric about us. But except for the obvious effects that are due to nearby obvious objects--like the Earth, the Sun, our galaxy--in practice the gravitational effects of the rest of the universe on us are negligible.

[unsupp0rted → mxkopy]

I don't think we know how small of an effect gravity can have over a large distance. Is there a lower Planck-like limit?

[pdonis → unsupp0rted]

> Is there a lower Planck-like limit?

Only in speculations that we have no way to test now or in the foreseeable future. We are many, many orders of magnitude away from being able to probe spacetime on such scales.

[mxkopy → unsupp0rted]

From my (complete lack of) understanding, it’s unlikely that spacetime is discrete, so maybe not.