http://www.hhmi.org/bulletin/nov2011/pd ... entist.pdf
SCIENCE ARTICLE PROOF:
“How fast would an object have to move to be invisible to the naked eye?
Could Dash from “The Incredibles” really run so fast that we could not see him?
The short answer is yes, Dash could run fast enough to be invisible. Exactly how fast he would have to run depends on many factors. For an object to be visible, light particles (photons) must bounce off the object and into your eye. There must be enough light that specialized neurons in the eye—the rod and cone cells that form the photosensitive pixels of the retina—are activated to a level that triggers awareness. If Dash zipped through your field of view so quickly that too little light from him reached your retina, you would not see him. What is the minimum amount of light required? In a classic experiment, people in complete darkness were exposed to flashes of light. Only the rod photoreceptors were sensitive enough to detect the light intensities used in this experiment. At the minimum flash brightness required to trigger visual awareness, onlya handful of rods each absorbed just one photon. The implication is striking: single cells, capturing single particles of light, can trigger perception. However, at best, the rods can provide only a low-resolution image. To see and recognize Dash requires cone photoreceptors. Cones allow high-resolution color vision in brighter light. Unlike rods, individual cones must absorb many photons to generate a sizeable response.
And since each cone contributes a single pixel to the final image, many cones are required to “draw” Dash on the retina. If Dash were moving fast, photons bouncing off him would be scattered across many cones, and each of these cones might be insufficiently activated, so Dash would be invisible. If there were just a little more activation, he would appear as a blur. The less light there is, the more Dash can afford to take it easy. At noon when there is a surplus of photons, he has to be at his speediest to be invisible. Other factors are at play. One is eye movement. We never look steadily at a single point in space. We are not aware of it, but our eyes constantly dart from one location in the visual scene to another. They make small jumps that last about a fifth of a second. These jumps are called “saccades,” during which our visual system is suppressed. If Dash shot past during a saccade, you would not see him. If he ran past a crowd, chances are that at least some people would be in midsaccade and would miss him. The bottom line is, a complete answer to your question does not exist. How much light is required for a good cone signal, how activity across the array of cones is assembled into an image, how the visual system shuts down during a saccade, and other factors such as attention are active research areas. Answered by Michael Tri Do,_ an assistant professor at Children’s Hospital Boston,Harvard Medical School.”
In sum: photons move at light speed, it is photons bouncing of the object that allow us to see it, if the object were moving faster than light it would be moving faster than the photons can bounce off and therefore would be "invisble" to a human eye.
http://media.animevice.com/uploads/0/94 ... _super.gif
ALL of the above confirm that GOKU CAN FIGHT AND DODGE AT MASSIVELY FASTER THAN LIGHT SPEEDS.
Now, do not misunderstand my point. My point is NOT that Z warriors ALWAYS fight at light speed and massively faster, far from it as there are many times at the World Tournament where the crowd is able to see parts of the battle. However, as the above physics article discusses moving at just under lightspeed is still able to be seen from all angles depending on distance, but to be truly invisible like some parts of the fights in Dragonball and onward means that the characters were fighting at at least Light Speed or Faster.
Thus, if you discount the proven Namek traverse speed analysis and the fighting speed anlysis in favor of one based on character depictions it only makes Goku even faster. This is because from Dragonball and onward the fighters are at least capable of fighting and dodging at light speed, but cannot necessarily always do it or cover a large distance at that speed based on how it is depicted in the story. BUT AGAIN we know Goku can cross Earth in one second as he did on Namek and that is his lowest proven speed feat so I am going to use that.
