[jmacusa]

True since, I believe that as you approach the speed of light, for the traveler time seems to be relative but to a stationary object much time has gone by. Which it would seem to me that if you could travel somehow to the nearest star or galaxy, before you'd even gone a quarter of the distance or less , everything and everyone you left on Earth would be long gone.

[C210N]

I forget the exact numbers, but they are known... but the ballpark is correct:

Only thing needed is an engine with constant acceleration of, say, a tolerable 1.1g. Aim the craft towards Alpha Centauri, and go. After about a year stop the engines. you’d be going 50% the speed of light. After 2 years, maneuver the craft around, light up the engine again, and start “braking”.

For someone on earth, time elapsed is about 7 or 8 years. For someone on board the craft, time elapsed is about 2-3 years.

There are online calculators where one can plug in various numbers for time, distance, speed, with constant acceleration in mind, to determine how long the traveler ages versus earthlings.