May be, we are the ALIENS

Maybe we'll develop the technology so much some day. That it'll finally be possible to time travel. We'll make the time machine.
But in this process we'd have destroyed our pretty planet. As we know about global warming at present.
And so we decide to time travel in the past on earth, to the time when the grass was greener, the sky was bluer and the water was abundant.
And maybe we'll be called gods that day.
Because we come from the skies and live far away in another world.
And we have all the modern machinery which a common man from the stone age sees as 'magic' because he doesn't understand how it works.
And may be on this day, it will finally be proved that we are our own gods.
May be it was us this whole time.