Time Dilation is Real Effect, Time Dilation in Relativity, What is Time Dilation?

TIME DILATION IS A REAL EFFECT - TIME DILATION IN RELATIVITY - WHAT IS TIME DILATION?

Time Dilation concept has been experimentally verified by an example of cosmic ray particles called mesons. Mu Mesons are created at high altitude in the earth atmosphere (=10 km) by the fast cosmic ray photons and are projected towards the earth surface with a very high speed of about m/sec which is 0.998 c. Mu mesons are unstable and decay into electron or positron with an average life time of about .

Hence in its life time a Mu meson can travel a distance

But the question is that Mu meson travel a distance of 10 km to reach the earth surface. This is possible by time dilation.

In its own frame, Mu mesons have an average life time is 

.

Now 

This example explains the presence of Mu mesons on the earth. Hence we can say that time dilation is real effect. 

Time Dilation, Time Dilation in Relativity, What is Time Dilation?

TIME DILATION – TIME DILATION IN RELATIVITY

The word dilate means “Enlarge beyond normal size”. Time is also not absolute but relative. It is found that a moving clock in the space craft appear to tick at a slower rate than the stationary one on the ground as seen by an observer on ground.

Thus if a clock moves with very high speed v relative to an observer then it appears to be slowed down or time to time interval is increased by a factor .

Let us consider two frame of reference s and s’. s’ is moving with velocity v relative to s which is at rest along +x direction. A clock is at point x in the frames. Let the clock give out signal at two instant t1 and t2 then the interval between signal is given by .

If the signal interval is observed in frame of reference s’ then interval  is given by

From Lorentz transformation equation for time

Hence for a moving observer, the time interval appear to be dilated (increased).This phenomenon is known as Time Dilation.