Time is actually what is called in science “space-time”. Space and time are inseparable. Time is considered movement through space. Thus a day, 24 hours, is the movement of the surface of the earth one revolution through space.
The past & future have duration. They can be measured. The present has no duration. How long is the present? You see! Feel into that which is not time.
Now, let go of time. Past, future, let go of it. All sense of measurement, space-time. What is left? The present, the witness of all that is. The witness of all that arises and passes away. This is what it means to be in the present. Not part of time, but part of something much greater, encompassing all that is yet simply the witness of it all.