Re: How well do we know the value of G?

[jacobnavia]

Le 10/03/2021 11:09, Phillip Helbig (undress to reply) a écrit :

> How well do we know the value of G?
>
> G is the constant (well, as far as we know) of nature whose value is
> known with the least precision. How well do we know it? Presumably
> only Cavendish-type experiments can measure it directly. Other
> measurements of G, particularly astronomical ones, probably actually
> measure GM, or GMm. In some cases, those quantities might be known to
> more precision than G itself.
>
> Suppose G were to vary with time, or place, or (thinking of something
> like MOND here) with the acceleration in question. Could that be
> detected, or would it be masked by wrong assumptions about the mass(es)
> involved?
>
> Just as an example, would a smaller value of G and correspondingly
> higher masses be compatible with LIGO observations?

There is a very interesting article in scientific american about this:

see

https://www.scientificamerican.com/article/physicists-measure-the-gravitational-force-between-the-smallest-masses-yet/

[Moderator's note: See also https://www.aspelmeyer.quantum.at/news/ -P.H.]