Every passing moment comes with a change. Change that is a subtle aspect of reality and makes life alive. It is buffering of events after events that shape sense of happening. It appears something just passed and something about to come. We can move back and forth, up and down, side to side in time but prisoned in a flowing river of time.
Unlike space, we are not able to move across the dimension of time at free will. It is not happening of things, rather events that move through the formation of time. No matter how fast or slow we become, time has its own pace. Time is one of those unsolved mysteries in modern-day physics. Think this way, if we could freeze each and every moment in time, all we would left be a collection of that past, present and future moments stacked together in the form of a record. Life can just be a record played in a divine cosmic game. Due to our body limitations and sense constraints, we perceive only present moment. But in reality, all past, present and future moments might exist altogether.
Time and space are not separate entities according to modern science. Time and space are intrigued together in a unified fabric of space-time. Even the Newtonian idea of time being universal and uniform everywhere is no more valid. It was during the beginning of 20th century, that famous physicist Albert Einstein came with a groundbreaking idea of time being relative. He gave rather a bigger and true picture of what reality might be.
Both time and space came into existence, the very moment big-bang happened. Some physicists tell time to be 4th dimension, space being in 3-dimensions. Whatever time might be, we have very little or no understanding of what it actually is. Essence of time is beyond our senses and the best of scientific instruments we have. Time is a mystery not only for scientists but for philosophers and poets too. Some philosophers consider time without beginning and end. They say, time is an everlasting loop running over and over and over again, while others insist on understanding present to feel true nature of time. People come and go, born and die just the way they are designed to perceive and that is the style of nature.
It is clear that we understand no aspect of reality fully and effectively. Maybe it is unknown nature and its enigmatic behaviour that makes time so amazing. No matter how aware we are, we tend to avoid present and remain thoughtful to memories of past and future possibilities. As human beings, we have to understand that being in present with our own inner being is the key to enjoy time. We all have a short time span in this life. All we can do is to live every moment and do our best each moment in time.