What is Time What is the Cause of Time

For thousands of years philosophers and scientists have struggled to understand the phenomenon of time. We have known for the last one hundred years about time dilation or slowing of time with motion and in gravity yet true understanding of time have evaded us. I believe there is a clear solution to the enigma of time. This brings to light the reason behind many predictions of Special and General Relativity such as why time slows with motion and in gravity? What is the cause of gravity and why it is only attractive? Why space is curved by gravitational fields? Why objects gain mass when accelerated by a force but do not gain mass when falling in gravity? What is the cause of inertia and length contraction and why there cannot be a twin paradox? The concepts are simple so that anyone with knowledge of high school physics and math should be able to follow.