That is Dr. Tyson's definition. Merriam Webster says : 1) a : the measured or measurable period during which an action, process, or condition exists or continues : duration b: a nonspatial continuum that is measured in terms of events which succeed one another from past through present to future - Like Steve Miller sang, "Time keeps on slipping slipping slipping into the future"'
As I queried last month when the topic was simply Time, Since we cannot bring back the past is time really anything more than the present? Is the future real before it becomes the present? The short answer is no to both questions in my opinion. But in reference to the period of reckoning, time can run out. It is like starting a discussion with a disclaimer like "For the sake of this discussion, the sky is orange with green stars" or a stadium's unique set of ground rules in baseball.
Then there are the Spanish scientists who believe time is literally running out and will simply cease to exist. Granted - they are thinking it will happen in billions of years but it certainly does make one stop and think. You can read about that here.
In the meantime, you might as well enjoy the present in any way you see fit. Me? I'll probably listen to the occasional song about time -
Be sure to check my cohorts blogs to see what they have to say about this week's topic- Ramana, Pravin, Maria and Ashok.