What Is Time? Sean Carroll

Dr. Sean Carroll, a theoretical physicist in the California Institute of Technology Department of Physics specializing in quantum mechanics, gravity, and cosmology, explains,

. . . it’s very tempting to wonder whether or not, like a filmstrip, moments of time are discrete. As far as we know, nothing in physics tells us that time is discrete. As far as we can tell, time is perfectly smooth and continuous.

The Great Courses Plus

What Is Time?, by Dr. Sean Carroll, 
https://www.youtube.com/watch?v=MAScJvxCy2Y