Time Dilation

Physics: AQA A Level, topic 12.3.3

Time Dilation

Time dilation causes a moving clock to run slower.

Time dilation

Time is different at different velocities within an inertial frame of reference.
As velocity increases, time will run slower:
$t = \frac{t_0}{\sqrt{1-\frac{v^2}{c^2}}}$
t is the moving time.
$t_0$ is the time at rest.
v is the velocity of the mover.
c is the speed of light.

Lorentz factor

The factor by which time dilates is called the Lorentz factor.
$\gamma = \frac{1}{\sqrt{1-\frac{v^2}{c^2}}}$
This determines how much time will differ.
As velocity approaches the speed of light, time will slow down.

Proof of time dilation

Proof of time dilation

Muon decay provides proof of time dilation.
Muons have a very short half-life, and should decay before they get through the atmosphere.
However, muons are still detected on the surface of Earth.
This is because muons travel so quickly, that time dilation provides them with more time to move.

Test yourself on Time Dilation

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