It is 500 years in the future. Man has perfected a way to travel to distant galaxies, and has discovered a planet much like Earth. In fact, it is ecologically just like Earth, with slightly less water and oxygen. However, after our initial explorations, it appears there is very little life on the planet. No advanced life whatsoever, only some simple vegetation in certain areas. We've explored the oceans and find nothing living there either. No signs of any kind of civilization, no intelligent life has been found, in spite of our advanced equipment which is designed to detect any kind of life as we know it. Aside from the rare and sparse vegetation, there is no sign of any life on the planet.
What we have discovered, is puzzling. The planet is full of mechanical devices of all kinds. Machines are running everywhere, producing things, computing things, making other machines. Some machines, we simply don't know what they are for, or what they are doing. There are buildings, but they are very simple structures, seemingly designed to just keep out the elements and protect the running machines. No bathrooms or running water, except where water is needed for the machines to produce. We've scratched our heads over this for a decade, and science is still baffled. Where are the people? Who made the machines? How did they get there? The questions are endless, as we grapple with the details of this new world.
The question posed by this hypothetical scenario... what is your conclusion? Did machines "evolve" into existence? Did some source of intelligence we can't detect or which no longer exist, make the machines? Is this some project erected by another civilization on another planet?