General relativity predicts that normal mass (positive mass) results in the curvature of spacetime which in return leads to gravitation. Since space and time are bonded together, any change on the fabric of space may inevitably lead to a change in time, as postulated by Einstein's theory of relativity. So the effect of positive mass on time is that it slows it down through the formulation of an attractive gravitational field, but what happens to time in the presence of [negative mass](http://en.wikipedia.org/wiki/Negative_mass)?