Or is it just that it can't be observed? This is a question that has been on my mind for some time, so i thought it worth asking here. Imagine the following scenario: Two space craft travel towards each other. Each travels at 0.6C relative to their point of origin (the points of origin being stationary relative to each other). Now as they both approach each other at 0.6, observers at the points of origin will be able to observe the distance between the two craft closing at a rate of 1.2C, breaking the rule of not travelling at a speed greater than 1C. What am I missing here? Thanks.