I've thought about this one a few times in the past and can't wrap my head around it, how can space or rather nothing actually curve to cause the effect of gravity? Is it possible that it just looks like space curves and it's actually caused by something similar to magnetism? Think about it, if something like magnetism worked similar to the effect of gravity, would it look any different to space curving? im sure they would look the same but one is reality and one is theory! Interesting thought to consider, note im not suggesting anything is wrong with current theory etc im just curious, thanks.