I have been thinking about the the experiment of 2 accurate clocks, one at ground level, and one elevated a the top of the tower, to show time dialation. I am a much better musician than I am an amateur physicist. And I understand the impact of pressure, rigidity, air pressure, and temperature have on musical instruments. If you take a drum, and start tightening the head, 2 things will happen. First, the pitch will go up when it is struck. The frequency at which that drumhead will resonate will increase. Second, the recoil or bounce of the stick will increase, as more energy is returned. My guitar hates it when I pull it from my 70F humid basement to a 85F dry porch. The tuning will change. Pressure, humidity, temperature, and gravity changes have a direct impact on mechanical devices and the frequencies they produce. This also applies to crystal oscillator used to keep time such as quartz. If this reliance on mechanical devices is to keep a frequency of time, how can this be deemed reliable? Could it be that perhaps the reason clocks that orbit the earth are slower is because the material they are built out of are susceptible to air pressure changes and gravitiational pressure changes that will occur as you increase altitude? In the twin paradox, twin A is out in space while twin B stays on earth, and 20 years later, twin A returns and might look younger because time slowed down. Now lets assume that mars had the same mass and atmosphere as earth. Would this apply if twin A camped out on mars for 20 years, or would they appear the same age again? The distance from them would be great. Should high altitude alternative cooking recipes really be labeled, "time dialation cooking instructions?"