Think of the days, when we started meditating. If we have taken a call of say fifteen or twenty minutes of meditation. A number of times a thought might appear that how much time is left. The meditator is thinking about time again and again. But when we have not fixed a time limit, then sometimes it may happen that after thinking about time, several times, we reach a stage, where we lose track of time. this is a deep meditational experience. Keep Meditating
