The present is the time that is perceived directly, not as a recollection or a speculation. The idea of present cannot be separated from a position in space. That is, the present is a point in space-time.
When comparing time in places separated by great distances, the notion of present becomes unclear. For example, we see stars as and where they were many years ago when the light just now reaching our eyes was emitted, because even though light travels at the incredible speed of 3.0x108 m/s it takes so much time to travel the great distances from the stars. The nearest star, besides our sun, is about four light years away meaning that it takes four years for the light to reach our eyes from that star.
Present as Illusion
According to scientific knowledge, primarily, the modern physics, what we usually understand by 'now', in some sense, does not exist. Furthermore, there is no provable reason why time should move in any one particular direction. This has led to the conclusion that the idea of a present is illusory and does not reflect the true nature of reality. The notion of "now" may be better understood as an unrealistic concept that has evolved in humans and animals to give us an understanding of reality useful only to the extent necessary for survival.
See Also
Bibliography
- Greene, Brian, (2004). The Fabric of the Cosmos: Space, Time, and the Texture of Reality. Knopf. ISBN 0375412883