As often as we hear about UFOs or whatever they call them now, the vast distances of space lead me to believe only a few possiblilities, other than it's all BS.The aliens put us here as an experiment and every once and a while they come back to check on us.
- They've always been here.
- They're from another time.
- They're from another universe/dimension/etc.
They got here OTHER than traversing incredible distances in space, even assuming faster than light is ever possible.