Results for "spaceship"


  • WilliamRivera

      Time Travel

      If humans were to invent a time machine in the future, why have they never traveled back in time to visit us? As far as we know, there are no records... The most famous argument against time travel asks what would happen if you traveled back in time and killed your grandparents before your p...

      Tags: time, travel, possible, spaceship, billion, miles