Hi There, I was doing so research and thought some of you guys may be able to help. Say I have a friend who is 18 days younger than I am. We both go to Egypt to visit the great pyramid of Giza. since the pyramid weighs 3,600,000 tons it has a high enough mass to slightly slow time around it. Say I stand one metre from the pyramid and my younger friend stands 1000 metres away, how much would time be slowed down for me relative to them and out of interest how long in theory would we have to stand there before my younger friend became older than me? Any help would be much appreciated! Thanks!