I have a problem with time dilation... You have all heard the story where there are two identical twins and one goes on the space ship and flies around at nearly the speed of light, comes back, and is still young while everyone on Earth, including the twin who stayed there, are old. But... What if you were the twin on the spaceship? You would see the universe moving around you at near the speed of light and time passing slower for it, and you would think that you grew old while everyone else stayed young, aye? If the twin on the earth sees the twin on the space ship as moving and himself as staying still then time dilation applies to the one on the space ship and they would see the twin on the space ship come back and say "Ooh, you look so young!" But if you were the twin on the space ship, the earth and everything would be moving relative to you, time dilation would apply to the twin on the earth instead of you, and you too would be like "Ooh, you look so young!" So depending on the frame of reference that you use for your calculations, a different person grows old... What am i not getting about this?