This may actually be a physics question... Einstein's special theory of relativity deals with time and light and how there is no absolute reference frame when you're talking about
when an event occurs. That is, something that happens simultaneously (e.g., I slam both my fists on the table at the same time) according to one viewer may not look the same to another viewer traveling close to the speed of light.
Here's a link:
http://en.wikipedia.org/wiki/Special_relativity
The invariance of the speed of light is key to understanding all of this.
In a way, the speed of light defines time. If you say that light travels, and you agree that the speed of light is always fixed (disregarding speed changes in different mediums) then I would say that time exists (provided we are moving slower than the speed of light).
If you want to think about it another way, if you concede that space exists, time must exist as well -- because light from the star travels through both space and time to reach your eyeball. Einstein talked about how space and time are one-and-the-same in his general theory of relativity. Most of the scientific community (if you have faith in them) accepts his theory.
Try some of his thought experiments and see what you come up with!