A few notes on speed...

The speed of light is considered to be the fastest that anything in this universe can travel.  This has remained true for all of history but perhaps we can do better.  The warp drive might actually be the key but we are still a ways off from making it happen.  How does it work?  The concept is simple.  

The speed an object travels is determined by the amount of energy the object has dedicated to it's motion.  This can be object generated energy such a human being walking or energy imposed on an object such as the effects of gravity on a rolling ball.  This is the simplest way of looking at it but there is another important factor.  Energy displacement.

Energy displacement could also be called matter displacement since mass is energy in a different form.  This is an easier way of understanding how it works.  When we travel at speed, we are traveling through a medium.  On Earth, the typical mediums traveled through are air and water.  

Air is a medium that is easily moved through by humans and their vehicles.  Despite our freedom moving around in it, there is actually quite a bit of matter that has to be displaced when traveling through it.  In water, there is even more matter that has to be displaced to allow us to move and thus slows our progress. 

If we are to expend the same amount of energy moving through water as we would air, we would travel at a slower speed.  There is more matter that needs to be displaced to allow our matter to occupy the new space.  So not only does the energy expended determine our speed but also the medium in which we are traveling.  Seems pretty sensible.  

If we travel in space, things become a little more complex but the general idea remains the same.  In space there is very little mass or energy that we have to displace when traveling.  This allows for much greater speeds with little energy needed to be expended.  Light traveling through a vacuum is considered the fastest that anything can travel.  It makes sense since it is pure energy traveling through a seemingly empty medium and the photon itself has basically no mass.  It is the perfect vehicle for achieving speed.

If we are to attempt to travel at that speed we run into a problem.  We have mass, which is energy trapped in a tightly packed ball that interacts with other energies in a problematic way when you want to go fast.  In space, as well as on Earth, that much energy must displace the majority of the energy it comes in contact with before it can move forward.  A photon can slip past the miniscule amount of energy in the universe because it has little to no mass and rarely interacts with other energies.  It barely exists.  It displaces almost nothing and thus achieves an impressive top speed.

A human wishing to travel at those speeds would have to be expending a huge amount of energy to attain those speeds because we would be constantly displacing energy we encounter.  The faster we go, the more energy we are encountering at any given moment which leads to more energy needed to increase our speed. This eventually leads to a balance problem when the amount of energy needed to overcome the energy displacement is unimaginable.  Our mass can no longer displace the energy in the medium and we are considered to have 'infinite mass'.  It's like hitting a brick wall while running flat out.  This problem kills our ability to travel the stars with any efficiency.  Unless you have a warp field.  

More on that later...