Some of my students chuckled and referred to people who follow the "flat Earth" philosophy, but I told them that one did not have to go that far to find people who still think in geocentric terms. I then suggested that they might have some geocentric tendencies themselves. I now suggest that those of you reading this might have them too.
Take, for example, the movie trilogy Back to the Future. In it, a modified Delorean with the help of a flux capacitor and 1.21 gigawatts of electricity can move through time. Once it hits 88 miles per hour, it disappears from its current space in time and appears in that exact spot in its target time period. The first experiment has it travel one minute into the future. It disappeared leaving a fiery future trail, and one minute later, appeared exactly where it had disappeared. That is geocentric thinking, as it would only work if the Earth were standing still.
However, our Earth is constantly in motion. Not only is it revolving on its axis and orbiting our sun, but our sun's system is orbiting the center of the Milky Way, which is moving through the Virgo supercluster, which is also in continual (and accelerating) motion. Should the Delorean actually travel through time to instantly appear in the same spot, the Earth would not be there to greet it.
For time travel to actually work, not only would time have to be bridged, but the physical distance in space as well. Perhaps this is why we haven't heard from any promising time travel inventors; their successful experiments are sitting somewhere in front of or behind the Earth's path.
This is one of many reasons why I would want the Tardis as my time machine.