ABSTRACT
In this chapter, we briefly discuss how the crucial concepts like space, time, matter, energy, causality which evolved during the last four hundred years after the advent of modern physics in the 17th century. The experimental discoveries and the required theoretical formulations have led to a drastic transformation of these concepts particularly after the recognition with the new sophisticated instruments microscopes, telescopes, accelerators that the universe has three domains, the micro, macro and the middle and these concepts have to fit into the explanation of happenings in all the three domains. The Big Bang Theory of Creation triggered by the discovery of the expanding, accelerating universe and which needs for explanation findings in General Theory of Relativity, the creation of particle and anti-particles discovered in high energy physics experiments, the Dark Energy and Dark matter overwhelming the contents of the universe, in comparison to baryonic matter that has been discovered earlier have all been explained. How all this leads to one strong but, tentative conclusion that the ultimate reality is most likely the “quantum vacuum” which is a combination of various energy fields, endowed with specific properties.
