Evolution of Time Concept in Physics and in Philosophy

What is ’time’? This is a question that has perplexed many a physicist and philosophers alike. The perception of the passage of time appears ingrained in all biological systems where growth, evolution and decay of objects, etc. are measurable indicators of the passage of time. Here we look at various physical models of time, from Newtonian to relativistic. We also explore the idea of perception of time including the possibility of travel into the past and future. Time in the quantum world (as measured by differences in energy transitions of various levels) and classical world (as energy transformations) are also discussed.