Albert Einstein developed the theory of relativity, that the closer an object’s speed is relative to the speed of light, the greater its mass increases and is contracted in proportion to the energy generated by its speed, and the slower the object travels through time, and that if one were to actually reach the speed of light, although theoretically impossible since reaching the speed of light would produce infinite mass, time would stand still. This increase in mass proportional to energy led Einstein to develop his legendary equation, and the time dilation caused by moving at high speeds through space led Einstein to think of time as the 4th dimension and that space and time were directly related to each other so Einstein referred to them as one entity, space-time. Einstein also did what Newton could not, discovering how gravity actually worked, that space-time is curved by energy and the mass of matter. The more mass or energy that is present, the greater the curvature of space-time. It is this curvature of space-time that causes objects to fall in towards each other. Since it is not only space that is curved but also time, Einstein discovered that the greater the force of gravity, the slower an object moves through time. Under infinite gravity time would stand still as it does for a beam of light. Light is the cosmic speed limit. Relativity may have metaphysical implications since all knowledge and evolutionary forms are understood relative to a point of reference, for example knowing a higher form by comparing it to a lower form. It is because of the theory of relativity that the nuclear furnace of the sun can draw energy from the matter it is composed of and that space-time is curved in such a way that the planets can revolve around the sun, this curvature causing gravity.