What is time? Obviously, the simple answer is the 24-hour daily cycle that’s broken down into minutes and seconds, to which we've all chained ourselves. But even in those minutes and seconds, the human perception of time is different for each specific person. When it comes to theories about time, that’s really the only thing that everyone can agree on. From there, scientists and researchers argue about whether or not time is experienced similarly by the earth’s population, or if time speeds up and slows down for people moving faster or slower. How we perceive time can not only alter our memories, but it can change the way we go about our days.
Is time linear? This is a question that’s plagued scientists and philosophers for centuries, and it’s likely to continue confounding them until time folds in on itself and puts the world's philosophers out of a job. (Unless that’s already happening right now.) There’s something noble about the study of time. No one will ever truly understand the "real" nature of the passage of time; all researchers can hope to do is try to figure out how we understand the way time passes around us.
There are some intriguing concepts on this list, and at least one of them, if not all, will make your head explode.