What's cosmic time? Do you consider time [ and space ] as an absolute phenomenon? If so, why? What I mean is, can we really define them in an absolute sense? How do you know what happened in the past, for example, other than making assumptions about the nature of time? This universe can disappear in the blink of an eye. What does it mean when we say that light cannot travel greater than a certain speed? There is more than one way of interpreting that. We can take "time" as an absolute, or we can take "space/distance" as an absolute .. but not both, according to the theory of relativity. We can also envisage a scenario in which our measured speed of light is not really "fixed" at all. It is all relative Relative to what we assume and define in the first place.