A hypothetical senario. As velocity increases time slows, time dilation. 2 observers 1 in normal earth time 2nd traveling at velocity where time passes at 1/2 rate. Both observers maintain same relative observational point. For sake of senario Light speed = 100 units per second. Measured course of 200 units. Beam of light shone down course, both observers start timers at start and stop timers as light passes the 200 unit marker. Observer 1s timer shows 2 seconds passed, observer 2 shows 1 second passed (1/2 normal time rate) Speed of light is constant for all observers so how can observer 2 time light at twice normal rate? Where is the above senario flawed? Please remember this is a hypothetical senario so how observer 2 maintains velocity is not important.