Again, I have to disagree.
It will take you something greater than 40 years in your time frame because you cannot travel faster than C. But for the observer's time frame it takes you some multiple of your shipboard time and that's the time dilation effect.
WHY do you think that? I have provided links to multiple site showing the actual equations, the math they imply and its application. Here is a link to a
nifty calculator that gives you ships time and stationary frame (Earth) time . IN reality of course the earth, the sun and the milky way are all moving, so aren't really stationary.. but now you are really complicating the math. I understand its counter intuitive and annoying the universe behaves in this way, but as far as we know, this is actually how it works. You have to remember the stationary frame is just a reference point. When you are on the ship - YOU ARE "STATIONARY" in the sense that your motion is not obvious to you..
You are NEVER at any point travelling faster than the speed of light ( as observed in the stationary frame) However, in order for your mass to travel at near the speed of light, time and space have to bend - and as a result you experience them differently. Your time will pass slower than the time on earth. When you slow down and re-enter the standard frame, 40 years will have passed on the clocks on earth, but MUCH LESS time will have passed for you, for the time you experienced was time (and space) as it behaves at near the speed of light.. (and speed is distance over time. ) Your "multiple" is a fraction. Time will have passed more slowly for you on the starship relative to the clocks on earth which still show you having spent 40 years in transit. If they could talk to you in real time you would actually seem to speak slower ( and with a doppler effect change on your voice) - and at extreme speeds, they would just have to record it and play it back massively sped up. because it would seem you were almost frozen... in a type of time stasis if you prefer. Your travel speeds itself is making the time pass slower for you relative to the people watching on earth. If you wanted to listen to a message from Earth you would have to slow it down. A Huge amount . The "relativity" is relative to the observer. Once you are both in the same frame again (because you slowed down and are no in sync with earths movement ( you aren't of course, but back to where they are nearly the same - like Florida and Colorado ) - you experience time the same way .
