Okie thats going to be fairly simple... All of the scientific facts about inter steller travels or even inter planetary travels in high or decent speeds have been allready writen in lot's of places... but i have only one thingy to say... if some little green man did come to earth after years (or even if they find a way to travel faster than L weeks) of space travel... and years of spotting a planet with life... DO YOU REALLY THINK THEY'LL BE PLAYING HIDE AND SEEK??? No? good neither do i...