Sometime earlier you wrote that there are no paradoxes in time tavel. I have a question regarding a paradox that I can’t seem to overcome. Maybe you can help.

People who posit theories of time travel generally write in terms of time travel in years. My problem deals with very short trips – the kind that early experimenters would most likely attempt (to avoid divergence problems if nothing else).

In this experiment the traveller only goes 30 seconds into the past to appear in his lab. It seems that 30 seconds before his experiment was to begin he saw himself apppear in the lab. There would now be two travellers and two time machines. It doesn’t appear that it ends that simply as the “second” time traveller says that he saw a duplicate self appear in the lab thirty seconds before he started the trip. It would appear that its a time loop and an infinite number of duplicates see a duplicate self appear in the lab thirty seconds prior to the start of the trip.

Your time machine weighs 500 lbs and an average man weighs about 180 lbs. So lets say that that the mass is about 700 lbs per traveller. What is the mass of the duplicates and where did the mass come from? What is the result of the duplicates arriving ~simultaneously at the ~same place and time? How long will it take for the loop to decay? Will it decay? Is it a loop? What happens if the experimenter, upon seeing his duplicate, decides not to continue the experiment?