The expansion of the Universe is an incredible phenomenon that has been studied by physicists for centuries. According to Albert Einstein's theory of general relativity, space and time are merged and nothing can travel faster than the speed of light. However, this does not mean that space itself cannot move faster than light. In fact, space-time can move faster than the speed of light relative to some other location, as long as the two locations cannot communicate with each other.
The expansion rate of the Universe is equivalent to an inverse frequency or time. This means that if you do the conversions and take the inverse of the expansion rate, you can calculate the time you will leave. This is because the density of radiation decreases slightly faster than the density of matter, due to its wavelength stretching as the Universe expands. Mass and energy warp space-time, causing heavy objects such as stars and black holes to curve it around them.
This curvature is what we feel as gravity and is why many space heroes worry about “getting stuck” or “falling into a gravity pit”. Early science fiction writers John Campbell and Asimov saw this deformation as a way to circumvent the speed limit. The speed at which space itself expands has no physical limits at its upper limit. This means that individual galaxies do not move through the fabric of space, but rather, it's due to the fact that mass itself, like the fabric of space itself, expands and the galaxies are ready to travel.
With each passing moment, each separate object moves further and further away, and objects that could previously be accessed cross that mark and become unreachable forever. The speed of light was found to be the same regardless of which direction an interferometer was facing, even with, perpendicular to or against the Earth's motion through space. This is because light redshifts due to the expansion of space, meaning that two galaxies end up much further apart than the path of the light that travels through the photon exchanged between them.
