 So here we have a familiar sight. Alice is standing in a train moving at speed V while Bob watches from the sidelines Now on the train is a light clock Alice measures the length of the light clock and finds it to be LA Now I'm going to make a crazy assumption Perhaps when Bob measures the length of the light clock, he might get a different value which will call LB Now what are TA and TB? The times Alice and Bob measure for a round-trip tick of the light clock