Human Brain has suprachiasmatic nuclei that can track time. Still human brain can increase or decrease speed of time. You must be wondering how human brain can change the speed of time? Yes, it is true that chemicals can excite neurons and make time go faster or decrease neurons firing and decrease speed of time. So let us understand how it happens? If we are having fun or enjoying ourselves we will feel that time travelled very fast whereas if we are in danger or in sickness, time feels to be traveling slowly. Even it has been seen that time travels faster for older generation than younger generation. Scientists believe that these perceptions are due to the fact that when more memories are formed, time seemed to travel slowly. Likewise when less memory is formed, time travels fast. This explains why for elderly people, time travels fast as less new memories are being formed than their younger counterparts. Many scientists have also claimed that our perception of time actually blinds out what is actually happening in time. The concept of time have evolved drastically since the time of its inception by mankind. Time was defined through several methods like science, philosophy, religion and arts. Though definition is different but measuring time is relatively same. So before defining time let us understand how time is measured. Time is measured by two forms that are calendars and clocks. While clocks looks into the time of one day where as anything over a day is looked after by calendars. Now since we got a bit of information about time, let us understand the definition of time that we started with initially. Time is defined as the progress of events from past to present to future. This definition has two distinct meanings. One meaning is that time travels in one direction only and that is forward. That’s why the definition states from past to present to future not the other way round. The second meaning is that if the events are not changed then it becomes timeless.