Palmer Luckey recently said he believes the most plausible answer is that they are beings from the past, since it's easier to go forward in time relativistically than it is to go backwards. Simple, plausible, but not richly compelling as to who they are or why us. Dr. Michael P. Masters theory is that they are an evolutionarily future version of modern humans, coming back in time as anthropologists (extratempestrials). Covers lots of ground as far as explanatory power with known events and co...