Re: what is time?
Now consider two populations of muons: 1. muons entering the earth's atmosphere from outer space: these are travelling at very high speeds compared to the observer.
- muons in a laboratory, which are taveling at a relatively low speed compared to the observer.
now, the observer measures after 10 seconds (from HIS OWN time) the amount of muons left in the observation he got from 1. and from 2. and he sees that there are more muons left from observation 1 than from 2.** This can only mean that the physical time for muon 1 compared to him is slower than muon 2 compared to him**.
But this also means that "TIME" is also relative to the speed? isn't it and why ignore the mass-enrgy conversion in muons? after all they are highly unstable particles.
And lets not forget, that this TIME measurment is also relative to OUR psychological perception of time. :-)