Four days, not bad. XD
Movie actually. A couple text each other as the girl who continues to go out further in space after being recruited to fight aliens takes longer and longer to reply due to the lag from the fact that EM waves have their own speed limit. Eventually, it takes her eight years for the boy, who is now a man, to receive her text.
That's a relative perception.
I don't know, who're you willing to stalk posts and all? XD