Your imaginary demonstration starts to reveal the problem, IMHO. Allow me to elaborate. Let us say that for any point we have whatever number of original observers and they all set off in different directions in pairs. At some given time interval one member of each pair stops and the other continues moving. Shortly thereafter all members observe the speed of light coming from the original point. According to Einstein everybody will get the same result. “There is no preferred frame of reference.”
That the speed of light will remain constant I can understand...sort of. But the time it takes for that light from the original point to the various observers, to my HS graduate thinking, should vary dependent upon distance from that original point.
Right, Wastoute... but go further, or else you’ll leave Roccus thinking it’s all simply bulls—t.
The fact that they all get the same result is where we get the notion of time dilation from. How can light appear to be traveling the same speed relative to you, regardless of your speed? The answer is that the flow of time changes, too.
OK, let’s make the math simpler and say light travels at 200,000 km/s.
You “chase” the light at 150,000 km/s. So light should now appear to be traveling away from you at only 50,000 km/s, right?
If I’m observing, standing still, you will indeed seem to be losing only 50,000 km/s relative to the speed of light. But to you, time will go by at 1/4 the speed, so in one of YOUR seconds, light will travel four times further, and to YOU, it will still be going at 200,000 km per YOUR second.