There are several theories and perspectives on the nature of time. I'll provide you with a brief overview of a few prominent ones. However, it's important to note that the nature of time is still a subject of active research and debate, and different theories offer different explanations.
Newtonian Time: In classical physics, time is considered an absolute and independent entity that flows uniformly and independently of any objects or events.
Eternalism: This viewpoint suggests that past, present, and future all exist simultaneously and are equally real. According to this theory, time is a fourth dimension, and events are spread out across it, much like objects are spread out across space. The "block universe" concept is associated with this theory.
Presentism: In contrast to eternalism, presentism argues that only the present moment is real, and the past no longer exists while the future is yet to occur. According to presentism, time is seen as a succession of distinct and fleeting "now" moments.
Relativity: Einstein's theory of general relativity revolutionized our understanding of time. It established that time is intertwined with space and can be influenced by gravity and motion. The theory also allows for the possibility of time dilation, where time passes differently for objects in different gravitational fields or moving at different speeds.
Regarding the question of whether time is infinite, different theories propose different perspectives:
Some cosmological models, such as the Big Bang theory, suggest that time has a finite beginning, often referred to as the "singularity," beyond which we cannot currently make meaningful observations.
On the other hand, certain philosophical and cosmological viewpoints propose the idea of an infinite or cyclic universe, where time has no specific starting point and continues infinitely into the past and future.
It's worth noting that our current scientific understanding is limited, and our understanding of time may evolve as we gain more knowledge and insight into the nature of the universe.