We all experience and have an exact idea of what time is. We know the past, the present and the future. But time is an anthropological construct, a measurable convention that attempts to frame the natural events that human beings have been observing since the beginning of civilization. Life on our planet is linked to the different cycles. The repetition of day and night, the seasons of the year, the hours of the day, the orbits around the sun and a life structured by time signals and the calendar, provide us with the experience of time as a constant flow that is repeated.
In our day-to-day lives, we continue to understand time with a Newtonian view and our perception of it makes us feel as if we live in a construction of reality that is shown through successive intervals of events. Under this Newtonian conception of the universe, artists have always tried to capture the idea of the cycles of time. From the first pictorial representations of the Egyptian world, through the calendars of Mesoamerican cultures or even in the European avant-garde (within the impressionist movement, where we can find the iconic pictorial representation of the different versions of the Cathedral of Rouen by Claude Monet showing the changes in light and color, through the passage of the different seasons). Also in music and literature, we observe how this cyclical idea has originated compositions such as the 4 seasons by Antonio Vivaldi or the poetic work; 4 sessons fill be the messure of the year by the English Romantic poet John Keats.
But in reality, current physics presents us with a totally different idea of time and induces us to think that the only thing that exists is the conception of the now. The past is memories and the future is expectations. The theory of relativity breaks with this linearity of time and shows us that the world in which we live is not really like that. In reality, our understanding of time is a strange concept. Time is not a universal constant, and thus the past, present and future are not absolute, but change through the eyes of the observer. Einstein's theory of relativity postulates that time is relative to motion in space, thus relative to the viewer's position on the observed phenomenon.
During our lifetime we experience time as a succession of continuous events, a series of images superimposed one on top of the other, which make up reality. But for any viewer who moves away from us at high speed, our present ceases to exist and can only access our past events (redshift effect). Similarly, if the observer approaches from a distant point in space at high speed, the observer will only be able to visualize our future events (Blueshift effect). Current physics presents us with the idea that there is no singular present, but that all moments are equally real and always exist in the now. Everything that has happened since the beginning of the Big bang until the moment when the universe will end, exists in a simultaneous now and only depends on the speed and distance of the observer to determine which point of reality he is able to perceive.