sci.physics

On 8 Sep, 08:26, Sven Geier wrote:
> Sam Wormley wrote:
>
> > o Gravity is unscreened. There are no negative gravitational charges to
> > cancel
> > positive ones, and therefore it is not possible to shield (screen)
> > the gravitational interaction. Gravity is always attractive.
>
> Last I checked (admittedly a while ago) nobody had ever accumulated enough
> antimatter to confirm that it does, in fact, have attractive gravitational
> properties.
>
> Unless and until someone manages to do that, I see no reason to prefer the
> expectation that antimatter falls downwards over the expectation that it
> falls upwards.
>
> Just a thought ...
>
Yes they have. There are virtual particles and if antimatter fell
upwards different substances would fall at different rates.

/wiki/E%C3%B6tv%C3%B6s_experiment

Current accuracy is 5*10^-13 - suficient I would say. Of course more
accuracy is always wanted. 10^-17 would ve nice.

- Ian Parker