I was just thinking about the past, present and the future. When I think about them in a narrow sense I get yesterday, today and tomorrow. I am of the opinion that yesterday and tomorrow have no limits. One can stretch yesterday backwards to any extent and can stretch tomorrow forward. All that has past will fall under yesterday and the entire future will come under tomorrow. But today is limited. It is too minute a period. It is the time between yesterday and tomorrow. We cannot stretch it backward or forward.
We generally understand yesterday as the previous day and tomorrow as the next day. Even in this case today does not change. It remains the same. It can even be reduced to the point of this moment.
I may be defying logic if I say that yesterday can mean the previous moment, the previous day, the previous week, month, year, decade, century and so on . Similarly tomorrow may include the next moment, day, week and so on. Yesterday or tomorrow cannot be fixed within a specific bracket. They are extendable periods while today is not so. It is too narrow. It is just the present. Nothing more and nothing less.