Thread:Mangetsu20/@comment-5651818-20130111221056/@comment-2089817-20130112050540

Since you're using science, or more specifically Physics, to explain this, allow me to clarify a few things.

No, it was not proven. Goku can't move at the speed of light. The mere thought of that is just... ridiculous. If he could, at a power level of 1500, he'd burn his body to ashes due to the friction on Earth, and also he wouldn't even need to use Instant Transmission on Earth. But he does. Not to mention, he needed the Flying Nimbus to bring him to the fight against Nappa and Vegeta, which already took quite a while, despite that the "speed of light" can travel across the planet eight times over in a single instant. Instant Transmission is the only true "speed of light" movement because he travels through a thread of ki that he connects with a location of his choosing, and considering that technique is faster than any speed Goku has ever displayed, he never reached the speed of light.

Roshi destroyed the moon but his power level was at MAX, not 126, as that power level denotes how strong he is when he was fighting Goku, and later on, Tien. It was far higher than 126, possibly even a 1000 considering it makes him so strong, it hinders his speed by a significant amount. Considering he was actually considering fighting Broly in his MAX form, for a short time, that alone should prove it.

Also, you forgot to mention that Goku isn't as strong as Superman physically. Yes, Goku can destroy solar systems and all that, but with Kamehameha. Not his fists. In fact, from witnessing what happens when he punches the ground after missing the target, all it does is displace a few boulders and large chunks of rock. But according to the references you've listed, Superman could actually drill through a planet. Not to mention that Superman's speed and flight are all derivatives of his superstrength ability. So, considering that his speed is from his strength, it can be presumed that he's faster than Goku (not including Instant Transmission), therefore he can dodge all forms of energy attacks as well and that makes it even harder for Goku.

In the end, a fight between the two of them is not a clear-cut decision. If it becomes only hand-to-hand, Goku has the better technique but Superman wins in brute strength, as aforementioned. If Goku uses Instant Transmission and Ki techniques, he'll most likely have the upper-hand, but Superman also has laser vision, which he could just make it more powerful to match the Kamehameha.

However, if you consider the fight, think about it like this. Individually, Superman has no limit. His source of power is the Sun, which is seemingly limitless, but ultimately a finite energy source which will weaken with age. However, Goku, through willpower (due to being a shonen hero), breaks through any limits, and since he's a Saiyan, his power will keep growing every time he loses. But Superman's will not. Sure, maybe Goku will lose the first time. And maybe the second time. And third. Maybe fourth. But eventually, he'll be so strong, Superman will no longer be able to keep beating him and he will suffer defeat. Not to mention, Superman can still age. His body will eventually get old and decreptive, but Saiyans stay young in order to continue fighting at an old age, as Vegeta stated and it was confirmed since Goku was still young and appeared to be in his thirties even as his great great grandson fought in the World Martial Arts Tournament.

So, to conclude, Goku will win in the long run, no matter how you look at it.