In 1905, Albert Einstein altered the course of scientific thought when he published his theory of special relativity. This groundbreaking concept, which proclaims that time is dependent on reference frame and spatial positioning, became a cornerstone in describing the time-space relationship.

Einstein’s theory of special relativity is based on two primary principles:

**The principle of relativity:**The laws of physics are identical on all inertial systems.**The principle of the speed of light:**The speed of light is the same for everyone, regardless of how they move relative to the light’s source.

The theory abolished the earlier notion of an absolute universal time standard and established a basic and important link between time and space. The universe has one time dimension and three spatial ones: up and down, left and right, and forward and backward. Taken collectively, this four-dimensional result is the space-time continuum.

Putting the two principles of special relativity together, Einstein drew the conclusion that space and time are actually relative. Objects in motion, he asserted, experience time at a slower rate than non-moving ones.

The theory met with some criticism, as the timeflow discrepancy could only be observed when travelling at light-speed, which was impossible in 1905. Experiments conducted in recent decades, however, have confirmed that time and space are perceived differently for objects that move near the speed of light. When atomic clocks are sent into space on high-speed rocket ships, the time they display upon return are slightly slower than Earth time, a process known as ‘time dilation’.

## E=mc2

This relative connection between time and space motivated Einstein to use the theory of relativity to come up with his famous equation E=mc2, which connects energy (E) and mass (m) with the speed of light (c). The equation represents his theory that as an object reaches the speed of light, its mass increases.

## Star Trek and the Time-Space Dilemma

The time-space relationship created a dilemma for the writers of Star Trek. They had to find a way to move the characters around the universe in a speedy and dramatic fashion: the slower sense of time that space travel brings on was inconsistent with the idea of voyaging quickly from one universe to another, but creator Gene Roddenberry wanted to stay true to the laws of physics.

Even traveling at the speed of light, it would take a starship hundreds, if not thousands, of years to go from one galaxy to the next. The solution? Roddenberry and his writers invented warp speed, which was much faster than the speed of light. Warp speed was, and still is, a mind boggling concept, but former NASA scientists say that it could actually be in the realm of possibility one day.