Einstein is the most brilliant person to ever live. So far. He came up with the idea that matter and energy actually mold the shape of space and the flow of time. Most of the things he did are very hard to explain. Have you ever seen or heard of E= mc2? Here is the simplest way to explain it. E stands for the energy in any amount of matter. That equals the mass (m) of the matter multiplied by the speed of light squared (c2). Do you get it?
In his lifetime Einstein created many things. 1905 was a very busy year for Einstein. He created four different theories and published two papers. One theory he created was the Special Theory of Relativity. That was done in only hours. He also came up with the quantum theory of light. That is the idea that light exists as tiny packets, or particles, that are now called photons. Einstein tells us that time is relative and that time of a moving object is slower relative to an object that is staying still.
Without Einstein we might not even be thinking of time travel.