what is the weak field limit?
Generally, it's when the field in question is small. With gravity, for instance, the gravitational field is small when you're far away from any massive objects.
like i said, i`m just an amateur but couldn`t the extra dimensions actually be visible as the expansion of space and that they are staring us right in the face. Also, the actual physical world isn`t limited to what science can test for. thank you for your answer on the afield limit.
Well, it is always possible to visualize curvature by considering a surface embedded in a larger-dimensional space. For instance, the surface of a sphere is a purely two-dimensional surface. We visualize the curvature of this surface, however, by looking at the surface in three dimensions.
One of the main insights of differential geometry (the mathematics behind General Relativity), however, is that you don't actually need to have extra dimensions to have curvature. The curvature in General Relativity (which is how the expansion is described: it's curvature in space-time) is fully depicted with no reference to any extra dimensions.
Er, but it is only stuff that we can test for, whether directly or indirectly, that we can be confident exists. The real world may well not be limited by our experimental abilities. And that's fine. But we had better limit ourselves to our experimental abilities lest we mislead ourselves.
thanks chalnoth but keep pushing that envelope out!
Separate names with a comma.