Hi All, I am new to these forums. I've been studying relativity in my down time at work and I am having a bit of trouble understanding why gravity doesn't offset velocity in the popular "aging/time travel" theory/scenario. I’ll explain: What I think I understand: The speed of light is constant everywhere. That is, if I am accelerating at the speed of light, the speed of light from that frame of reference would still move away from me at the speed of light. Conversely, if I am standing completely still, the speed of light will again, move away from me at the speed of light. Because this breaks the laws of physics regarding the relationship between time and distance, the faster you approach the speed of light, the slower time will move to offset your current velocity to ensure the speed of light remains constant from all frames of reference. This is why the theory of someone on a rocket ship travelling at the speed of light or close to it can return to Earth in, say, 24 Earth hours for example, but find years have passed on Earth in that time. Here’s what bothers me: I’ve heard the following things: 1) Velocity slows down time for the reasons I’ve explained above. 2) Time in space passes more quickly where there is no gravitational pull nearby. 3) Gravity slows down the passage of time. So, my question: If both gravity and velocity SLOW the passage of time, then why (in theory) when I return to Earth after 24 "Earth hours" travelling at the speed of light, would I find that everyone has aged many Earth years, if BOTH my velocity slows the passage of time AND Earth’s gravity slows the passage of time? Both effects slow down time, so why does everyone standing still under gravity’s influence age significantly faster than I do under velocity’s influence if BOTH variables have a slowing effect on time? I would think the only logical way (assuming the points I’ve heard are correct) I could age faster than Earth’s population would be if I was floating in space, far away from any type of gravity source, as I would then have neither the variable of velocity or the variable of gravity to slow the passage down. Any insight is very much appreciated.