Build Your Own Time Machine

Anything moving at near the speed of light, Einstein realized, would experience phenomena totally different from the everyday.

However, we can’t dismiss that “glittering metal framework,” as the time machine is first described in the 1895 novel—it is hugely significant. Although traveling in time was not a new idea even then, fictional time travel before that book had relied on dreams or magic

Special relativity provides a double opportunity for time travel. If you travel at a sizable fraction of the speed of light, time for you slows with respect to the outside world. In effect, you move forward in time. And if you can travel faster than light, you will have a means to move backward in time.

And because there is no special frame of reference, the view of the observer on the moving train is as valid as the view of the observer who isn’t moving. Either two events can be simultaneous, or one can come after the other, depending on how you are moving.

From this simple idea would come Einstein’s masterpiece, general relativity. This builds on the concept of special relativity to take in the real world where we aren’t restricted to steady motion, and acceleration and gravity play their part. But general relativity is much more than an enhanced version of the laws of motion. It describes the behavi

On the Electrodynamics of Moving Bodies

All movement has to be relative to something, and when Einstein was floating along with the sunbeam, it was not moving with respect to him.

But Wells transformed it into science fiction (even though that term was yet to be invented), a fictional concept of practical, solid achievement, opening up speculation about how time travel might be achieved and what the implications of traveling back to the Crucifixion, or visiting the far distant future of humanity, might be.

However, most of the real mechanisms for time travel will involve moving spatially as well, reflecting the way that time and space are inextricably linked in the four-dimensional matrix of space-time.