So, my father has recently taken a (very skeptical) interest in science, specifically physics and cosmology. Based on what he has seen from the various documentaries and reading he has done, he cannot grasp how Newtonian time can be incorrect in the sense that bending space with gravity affects the passage of time. In his mind, time is necessarily constant and unchanging, and since time itself is not a particle (which it might be; you know gravitons and all that) it absolutely cannot be acted upon by particles which exert gravity. He cites his own logical deductions such as "100 years before the big bang was still 100 years before the big bang, whether or not there was anyone there to measure it" and "The difference in time of two observers such as Earth compared to the ISS is meaningless because they are simply observing it differently and time itself has not actually been affected" He also considers time and space being inter-related to be nonsense, and that if you destroyed the universe, the passage of time would still take place in the resulting nothingness. Can someone clear this up for me? Does he actually have a point here? Is there an easy to grasp explanation if not? Thanks for any help in advance.