It seems to me there is a problem with special relativity - at least involving a particle which is commonly used as evidence to support it! Am I missing something? Here it is: A spaceship is stationary in space next to the moon. An interstellar muon travelling near the speed of light passes through the front of the ship, and - even though it's half life is much shorter than the time it should take to travel through to the back of the ship - it still survives to make it through the back end. This has been used to prove that time slows down as per SR when things travel fast. Now, if instead, the muon is stationary, and the space ship is travelling near the speed of light (the same as the muon was but in the opposite direction), the muon will be inside the spaceship for the same amount of time, but in this case it will decay before leaving the ship because it's time is not slowed. So for the passengers of the ship, in one case the muon will decay, in the other, the muon will not decay. Where is the relativity?