
- Continuing with the moun problem from the previous page. Say the ground is 10 km down.
- How far down would that be according to the frame of reference of the muon travelling at 0.9992c?
The gamma factor is 25, so we get - How long time would it take for the muon to reach the ground, as seen from the frame of reference of the muon?
- Will it reach the ground?
1.34·10-6 s is quite much smaller than the half-life 2.2·10-6 s, so, most likely, yes.
- How far down would that be according to the frame of reference of the muon travelling at 0.9992c?
- What speed would a spaceship have to have to be seen as half as long as its proper length?
We have
for L=L0/2, so
or
This gives us
or

