We think the Earth goes round the Sun and the Moon goes round the Earth. So at the end of a year the Earth is in the same place as a year ago. Right? Wrong! The Galaxy is spinning and the Sun moves with it through space. The Earth orbits the Sun but because the Sun is moving the Earth spirals along around it, and the Moon curves and spirals round Earth. So hard to try and draw! If we could time travel we would have to move through time and space to get back onto the Earth. But if you take into account the speed we are travelling and the distance we will have travelled around the Galaxy, I imagine it would take a great deal of energy to do it!