UNBELIEVABLE: Interesting timeline history comparisons | History Defined

Time is a fascinating concept when you really stop to think about it. During a slow workday, an hour can feel like it lasts forever, and a week can seem to drag on endlessly. Then you blink and somehow five or ten years have passed. 

We rely on seconds, minutes, hours, and years to keep our lives organized, and these measurements are essential for everything from science to catching a train on time. Still, the numbers on a clock do not always match the way time actually feels while we are living through it.

Humans have been trying to understand this strange idea for thousands of years. According to EBSCO, the ancient Greeks had two different ways of thinking about time. They used the term chronos to refer to time moving forward in order and the term kairos to describe the right or meaningful moment to take action.

Philosophers also disagreed about whether time existed on its own or depended on humans being there to experience change. Aristotle, for example, saw time as a way of measuring change, which shows just how long people have been asking questions about what time actually is.

Of course, people still needed practical ways to keep track of it. Before clocks existed, ancient civilizations watched the movement of the sun and stars. 

The Sumerians and Babylonians used a number system based on 60, which eventually helped give us the 60 minutes in an hour and 60 seconds in a minute that we use today. 

Ancient Egyptians helped develop the idea of dividing the day into 12-hour sections. Over many centuries, different systems slowly came together and gave us the familiar way we measure time now.

The funny thing is that our brains do not seem to experience time as neatly as our clocks measure it.

Psychologists began studying this more scientifically in the late 1800s and found that people do not directly sense time passing. Instead, we notice events happening and changes taking place around us. 

Our brains then use that information to understand what happened first, what came next, and roughly how much time may have passed. Scientists still do not fully understand the exact mechanism behind this, and time perception appears to involve several different parts of the brain.

One possible explanation lies in the chemicals involved. EBSCO notes that dopamine and norepinephrine have both been linked to the way we experience time. 

Dopamine is part of the brain’s reward system and is associated with pleasurable experiences. Researchers have found that it seems to speed up our perception of time, which may help explain why we often say that time flies when we are having fun.

Norepinephrine, meanwhile, is released during stressful or dangerous situations and appears to slow our perception of time. This may be why people who experience accidents sometimes describe events as happening in slow motion.

Scientists think this response may have been passed down from our ancestors because it helped them survive life-threatening situations. When faced with a predator, feeling as though time had slowed down could give them more time to process what was happening and decide whether to run or fight.