Build Your Own Time Machine

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

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.

Since 1895, when Wells published his book, science has moved on with frightening speed. And that progress has included the theories that makes time travel possible in principle.

It all comes down to the relativity of simultaneity.

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

Two absolute essentials of real time travel are the linkage of space and time, and the influence of gravity on the space-time continuum.

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.

On the Electrodynamics of Moving Bodies

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

This different way of looking at light not only explained the photoelectric effect, but also provided the foundations of quantum theory.