# Starter of the Week: 12 – Time Dilation

This starter is as follows:

One of the most incredible discoveries in human history has been that time is relative rather than absolute.  This means that all clocks – digital, mechanical and biological tick at a different speed for someone in motion relative to someone at rest.

For someone travelling at v m/s, the time they experience passing, T_0, compared to a stationary observer, T is given by:

(a)        A pilot brings a stop-watch onto a plane.  He flies at a constant speed of 300 m/s for 24 hours as measured on his watch.  How much more time has passed for a stationary observer on the ground?  [note: try this on your GDC first then try Wolfram Alpha].

(b)       The Parker Solar Probe (above) is the fastest ever man-made object.  It has recorded speeds of 148,000 m/s as it accelerated due to the Sun’s gravity.  If this speed was maintained for 10 years, how much time would have passed for a stationary observer on the Earth?

(c)        A rocket propelled by a solar sail is regarded as feasible technology and would be able to reach speeds of 30,000,000 m/s.  If this was sent on a 100 year mission how much time would have passed for a stationary observer on the Earth?