Space Aliens

They who claim to have seen or been abducted by space aliens are either very delusional or are just plain and simply lying or they may have been deceived by others most conniving. These aliens possess a torso, four limbs and a head for a body and these are traits that have evolved here on planet earth only. Every specie here on earth that displays a face all have the same ancient common ancestor from whom they evolved that trait. The odds of such similarities occurring in outer space beyond our reach are profoundly astronomical at the very least. I do however have one other theory that may shed some light on this space alien query. They are not space aliens at all. They are the future of humanity who have traveled back in time to study their evolutionary history. We now travel in automobiles where we once used horse and buggy. We've created trains and airplanes so as to travel more quickly. We now have the Internet whereupon we once depended on libraries only. Our advancement is evolving exponentially. So I ask you; Is time travel so inconceivable to be attained eventually? Every so called alien looks like a clone to me. Perhaps they are all fading out very slowly and can no longer procreate as do we. Cloning a clone is like making a photo copy of a photo copy. The image through many generations begins to fade eventually. So maybe they're abducting us to extract our DNA to preserve their specie. As far fetched as this may sound, it makes scientific sense to me.