What is Time?

What is time? Time is an emergent concept, Time, Nature of time, What causes time? Why time slows in gravity? Why time slows with motion? Is time a dimension? Why Gravity is only attractive? Length contraction. Black holes, singularity Is universal expansion accelerating?

What is Time?, Time is an emergent concept, Time, Nature of time, time dilation, length contraction, inertia, gravity, expansion of the universe, accelerating expansion, twin paradox, inertia, Einstein, singularity, black hole, speed of light,