The phrase "time runs slower wherever the gravity is strongest" is a consequence of the warping of space-time, as described by the theory of general relativity. According to general relativity, the presence of mass and energy curves the fabric of space-time, creating what we perceive as gravity.
When space-time is curved due to the presence of a massive object, such as a planet or a black hole, it affects the flow of time. The warping of space-time causes a gravitational time dilation, which means that time runs at a different rate depending on the strength of the gravitational field.
In regions where the gravitational field is stronger, such as near massive objects, the curvature of space-time is more pronounced. As a result, time runs slower relative to regions with weaker gravitational fields. This phenomenon has been experimentally confirmed through various observations and experiments, such as the Pound-Rebka experiment and the measurement of time dilation using atomic clocks.
In summary, the phrase "time runs slower wherever the gravity is strongest" highlights the connection between the warping of space-time caused by gravity and the observed effects of time dilation in strong gravitational fields.