The Nature of Time

Abstract-One of the most fundamental concepts in our experience of existence is the flow of time-continuously from the past to the future. Yet, the basic nature of time as part of the description of the universe is not understood at all. The conservation laws of physics seem to be time-sym-metrical, every detailed action could occur in reverse, which argues that the concept of the passage of time is not needed in nature. Yet, that time flows in one direction remains part of our experience. Can time stop? Can we influence the future? Can we influence the past? The historical and thermo-dynamic arrows of time are discussed and several enigmas and contradic-tions about the nature of time are revealed. The concept of "entropy " and its relation to the universe as a whole is explored. The fundamental changes of our notions of a uniformly flowing time, made by Albert Einstein in his Special and General Theories of Relativity are pointed out, and several "paradoxes " and "anomalous " examples are described. The nature of time and its relation to the Big-Bang cosmology is dis-cussed, and the question "What was before the Big-Bang " is addressed