From my paper on the development of warp drive:

Why is this barrier so daunting to astrophysicists? This question can best be answered by Albert Einstein. In 1905, he published the Special Relativity Theory, which describes the physical conditions of objects in motion. Einstein theorized that in a vacuum (also known as free space) where there are no particles of matter, gravity and other universal forces were constant and the speed of light would also be constant to any outside observer, regardless of the observers’ motion in relation to the light source. This provided the constant in Einstein’s famous formula for Special Relativity: , where

is the speed of light, a constant in free space.cThe theory of Special Relativity goes on explain that as an object moves faster and faster, approaching the speed of light, the physical properties exerted on it change dramatically. Specifically, perception of time changes and mass begins to take on properties of energy rather than of typical massive matter. As such it was theorized that an object could not be accelerated to the speed of light without changing the nature of the object in some way. Once this happens, the object becomes the same energy as light when it travels at this speed, and thus cannot naturally travel faster.

So how then, if an object cannot even move at the speed of light in normal spacetime, does an object move faster than light? In 1915, Einstein published the General Relativity Theory, which mainly describes his concept of how gravity actually works in relation to Special Relativity. In this theory, Einstein explained that gravity is one of many dominant forces playing on the universe. These forces affect both space and time as a single dimension that exists around us, known as spacetime. In this model, spacetime is altered by gravitational pull, as well as the pull of the other forces expelled on the universe. These forces play dramatic roles on our understanding of physics and the how the universe works. It alters our perception of time, space geometry, dimensional space, light, and many other oddities that exist in our universe.

Spacetime, Einstein believed, could be viewed as a sort of fabric that stretches across the universe. Gravity, created by a mass, would be like placing a weight on the fabric, which would sink where the weight had been placed. If you were to put a ball bearing on the cloth and let it roll freely, it would become attracted to the weight’s impression on the material. This is how gravity is believed to work, and subsequently, gives light to the nature of normal spacetime; it provides the idea that spacetime can be and is curved.

This concept allows for the possibility of an object travelling faster than the speed of light if spacetime is curved around the object. Einstein himself offered his thoughts on the subject with the equation

=, where is the Einstein Curvature Tensor (which describes the curvature of space), andis the gravitational constant. In this model, the object is not technically exceeding the speed of light, it simply appears that way to an outside observer. The question then becomes how to create a curvature of space and how can that curvature be used to accelerate an object past the speed of light (and what would happen to that object when it reaches those speeds).G