Question

Why is time on earth and space different?

Answer 1

Hint: To explain this phenomenon, the concept of time dilation is used. Time dilation is the widening of time intervals as measured by two clocks. Two factors are responsible for time dilation-relative velocity and gravitational potential. It happens at relativistic speeds, i.e., the speeds which approach the speed of light. This also points towards the relative nature of time.

Complete answer:
Time dilation is the lengthening of the time interval between two events for an observer in an inertial frame that is moving with respect to the rest frame of the events. Hence, time has different values when measured from different frames. Suppose, for example, an astronaut measures the time it takes for a pulse of light to travel a distance perpendicular to the direction of his ship’s motion which is given to be relative to an earthbound observer.

The elapsed time for this event would now depend on which observer is measuring it. The time measured by the astronaut within the spaceship where the astronaut is at rest is smaller than the time measured by the earthbound observer relative to whom the astronaut is moving. Hence, we can say that the time elapsed for the same process is different for the observers.

While we are in space, we deal with relativistic velocities which are velocities that approach the speed of light in magnitude. So, this effect becomes dominant and hence, we observe different time intervals for the same event. As far as events on the earth are concerned, the velocities are very small as compared to the speed of light. Hence, the time dilation effect nullifies and we observe a different time interval for the same event.

Note:This time dilation effect happens in real life and is not a consequence of malfunction of any clock. Moving clocks always tick slower. This also happens in the biological clocks like the cardiac rhythm but the effect is too feeble to be observed without any sophisticated equipment. At low velocities, relativity seems to approach classical physics which explains our daily life phenomenon.