You arrange to meet a friend at 5:00 p.m. on Valentine's Day on the observation deck of the Empire State Building in New York City. You arrive right on time, but your friend is not there. She arrives 5 minutes late and says the reason is that time runs faster at the top of a tall building, so she is on time but you were early. Is your friend right? Does time run slower or faster at the top of a building, as compared with its base? Is this a reasonable excuse for your friend arriving 5 minutes late? You arrange to meet a friend at 5:00 p.m. on Valentine's Day on the observation deck of the Empire State Building in New York City. You arrive right on time, but your friend is not there. She arrives 5 minutes late and says the reason is that time runs faster at the top of a tall building, so she is on time but you were early. Is your friend right? Does time run slower or faster at the top of a building, as compared with its base? Is this a reasonable excuse for your friend arriving 5 minutes late? Time runs slower in a stronger gravitational field, so it goes faster at the top of a building, which is farther from the source of gravity (Earth) than is the base. This effect, however, is extremely tiny in a gravitational field like Earth's and impossible to measure without an atomic clock, so this is not a reasonable excuse to be 5 minutes late. Time runs faster in a stronger gravitational field, so it goes slower at the top of a building, which is farther from the source of gravi