“The earliest time measurements were observations of cycles of the natural world, using patterns of changes from day to night and season to season to build calendars. More precise time-keeping eventually came along to put time in more convenient boxes.

But what exactly are we measuring?” —Ted-Ed

Andrew Zimmerman Jones is an author of non-fiction and fiction, mostly in the areas of science and science fiction. His writing takes complex scientific and philosophical concepts, translating them into terms that are accessible to all readers. In this video, Jones contemplates whether time is something that physically exists or is just in our heads.