So you got person A on earth writing code and person B going around REALLY fast (very close to the speed of light lets say) writing the same code.

When person A finishes (say a week later) and comes back, he'll find that person B finished "a long time ago." That is, person B finished, and then waited till person A came back (say for a year, depending on how fast person B was going).

What happened? Time went at different speeds for each person. They each took a week from their own point of view!

Which one is right? Both of them. Thats what relativity says. There is not one thing called "time" but that its "relative" (hence the name).

So, if your going to choose to hire one of them... you'd hire person B (assuming your business is on Earth).