Brooo what if there used to be humans on mars but we messed up that planet so ad that we had to escape but only one escape pod ever made it to earth ,and what we call aliens is just all the other lost pods they just had to evolve to live up in space and when ever they come to earth they think we are the aliens so they never stay they just observe. Ok no remember that one pod that made it too earth the people on that pod were adam and eve whom populated earth.. Hey i mean im just saying.