I usually don't like to post responses to other writeups but there is one important point that needs to be made here. Many people are saying things like "Everything in the universe is moving at high speeds. If you moved through time and remained in the same place, you would be nowhere near the Earth." They are ignoring the meaninglessness of phrases like "high speed" and "same place" without a point of reference. Someone said the point of reference should always be the center of the universe? We aren't even sure the universe has a center.

The fact is, motion and position are never absolute. But acceleration is. Acceleration is always coupled to a force, which requires energy. That's why, no matter how fast or in what direction we're moving, we continue moving in a straight line (or a gentle curve because of things like gravity) called a trajectory. If whenever you used a time machine you jumped a couple grillion light-years off your current trajectory (or your trajectory extended back into the past), it would require, how do you say?, a shitload of energy to produce a force to cause that massive acceleration. If your time machine did nothing except move you through time, you would stay on the same trajectory you're following now, the one parallel to that of the Earth.