Because there is nothing particularly special about a clock. A clock is merely a device for accounting a sequence of events in time. As a person of habit can be used to set ones watch by, cesium atoms are only of a more stringent habit.
Cosmic ray particles slamming into our upper atmosphere produce daughter particles that should decay before making it to the surface of the Earth. So how is it that they make it down here where we can measure them. By theory, if a daughter particle were moving at 87% of the speed of light a real slow poke it should "live" twice as long as we would expect if its time were the same as our own. And this is what is seen.
Are we measuring a changing habit of a particle or a habit of space-time? Take your pick. Either all particles and events without exception behave exactly as if time has changed for reasons only beknowst to themselves or time is not the same to all observers.
AbE: cavediver, I'm not really sure this is on topic or not because I'm not really sure I (come anywhere close?) understand what the topic is. There is something I vaguely recall about "Why is there something instead of nothing?" I don't know where that comes from so why haven't I Googled it already? Let me Google it and get back to you with something worth the time (no pun intended). Thanks, I always like reading your stuff.
Edited by lyx2no, : Hit the topic somewhere.
Edited by lyx2no, : No reason given.
Genesis 2
17 But of the ponderosa pine, thou shalt not eat of it; for in the day that thou shinniest thereof thou shalt sorely learn of thy nakedness.
18 And we all live happily ever after.