Light speed, 299,792,458 meters per second or 186,282 miles per second,
     is a strange creature. Say you have a very powerful spaceship, and you
     kick in full power, and leave it there forever. The spaceship can never
     reach the speed of light. Nothing goes faster than light, and only
     light can go light speed. This is easier to picture if you know that
     mass and energy are different forms of each other. Light is called
     electromagnetic energy, and includes radio, microwave, infrared,
     visible, ultraviolet, X-rays, and gamma rays; from low frequency to
     high. Only the visible portion, (a small portion), is something we can
     see with our eyes. All frequencies of light travel at the same speed.
     In the graph named "Never", the purple curved line represents your
     speed in the spaceship. The gray horizontal line will never be reached
     by the curved purple one. (Of course, the picture isn't perfect, we are
     limited by the resolution of our computers). But this makes it easier
     to visualize. The bottom red horizontal line is the X-axis, and motion
     to the right indicates force exerted by the spaceship engine. The
     vertical red line is the Y-axis and upward motion indicates increasing
     velocity, a function of the force of the engine.