A long time ago, like the 1800s when the west was wild and wars were civil, scientists were interested in a great many things including light, electricity, magnets, and getting laid. They used to think that light traveled through a luminous ether, a field of something that permeated the universe, through which light traveled.
Around this time, my boy Michael Faraday
had been playing around with the electricity and magnets for a while and had noticed some pretty cool things about their nature.
He hooks up with the #3 physicist of all time, James C Maxwell
who used all this data and dropped a bomb known as "On the Physical Lines of Force" where he debuted the Maxwell's Equations.
With these equations, Maxwell had shown the general and predictive understanding of electromagnetism. This united all the there-to-fore misunderstood observations of light, electricity, and magnetism into one field. He lit up the scientific world. Electricity and magnetism could no longer be thought of as different, but rather intertwined observations of the same underlying phenomenon. Light became a self-propagating wave of electromagnetic fields.
Scientists minds were being blown that Maxwell had developed such amazing equations. Anytime people set out the verify that they were correct through experiment, they turned out to be correct. They proved themselves to be incredibly robust at generalizing and predicting nature.
One of the fun little tid-bits from the Maxwell's equations is this:
An equation which defines the speed of light in terms of the electric and magnetic constants, strangely as one speed.
Then the number #2 physicist of all time,
says, "You know what's strange? This awesome equation is without a reference frame. No matter how you design the problem, the term is invariant. Light travels at only one speed... I wonder what that means..."
A reference frame is like saying that you're moving at 0 mph when you're siting still according to an Earth Centered reference frame, but you're flying at who knows how fast in a Sun Centered reference frame. Light travels at the speed of light according to every reference frame.
He says, what if we have a clock which is just two mirrors with a beam of light bouncing between them. 1 bounce back and forth is one unit of time. We're watching this clock and it clicks off units of time at a regular rate. Now let's say that we're inside a train, watching the beam of light go up and down, up and down. No big deal. But what if someone was outside of our moving train, looking at the same clock. Well, now the light isn't traveling up and down, but also forward. It cuts out a larger path through space according to the outsider. He sees your clock as going slower, as the light is traveling a larger distance to bounce back and forth.
Bam, special and general relativity, a new understanding of space-time and gravity. Einstein says, and experiment confirms, that you can't go faster than the speed of light because the universe itself prevents it. Either time will slow down, space will stretch out, your mass will start blowing up, E=mc^2 (plus some other term no one ever talks about).
Nothing goes faster than light because the universe is built to cheat you out of ever breaking that speed. To travel faster than light, means to travel backward in time as light itself doesn't even travel through time.