Can Superman Outrun The Flash?: A Speculative Essay
Thank you for this question: Can Superman outrun The Flash? This is one of the oldest questions in the comics/cartoon world. I think there is a logical way to proceed. I think a good place to start is to evaluate the strength of the forces, which acted upon both men to give them their superpowers.
As we all know, for Superman, Kal-el, the Kryptonian, the Earth's yellow sun and lighter gravity endowed him with his frankly god-like plethora of powers, including the ability to run at superhuman speed. Flash is an Earth man, whose "real" name I have forgotten, but a native Earth man. His powers come from a sort of alternate dimension, the SpeedForce, or something like that.
From what I very vaguely remember about the SpeedForce, it is an empowering dimension, which very few mortals are sensitive to or can access. I suppose there's a genetic factor -- much like "The Force" in Star Wars, in which the most powerful Jedis and Sith have the higher chloridion counts in their blood, and so forth.
The question would seem to be: Which has the greater superempowering affect: the Earth's yellow sun and lighter gravity or the SpeedForce?
From the evidence we have so far, its hard to make an assessment. There is a complicating factor. Superman and Flash come from two different species of sentient beings. The former is a Kryptonian and the latter is an average human being. Its an apples to orange problem, isn't it? But there's at least one more thing we can do.
We might ask the question: which group start off as physically superior before being endowed with superpowers: the Kryptonians or Humans? We know perfectly well what the effect the Earth's yellow sun and lighter gravity has on Kryptonians.
What would happen if humans went to Krypton? With Krypton's much, much heavier gravity, human beings would presumably find it difficult to even move around, much less leap tall buildings in a single bound and outrace a speeding bullet. Therefore we have to conclude that Kryptonians are innately physically superior to Earth-born human beings.
Still, that leaves us with another question: Does the Earth's yellow sun and lighter gravity have a greater superempowering effect on Kryptonians than the SpeedForce has on human beings?
You know what might be fun to do? Switch forces. What would happen if a human being were exposed to the Earth's yellow sun and lighter gravity....... Oh, but we know what happens, right? A whole lot of nothing.
But what would happen if a Krytonian were exposed to the SpeedForce on Krypton? Let's not expose a Kryptonian, already given god-like powers via Earth's atmosphere, to the SpeedForce on Earth -- that would just be too much!
If a Kryptonian, on Krypton, were exposed to the SpeedForce (there's nothing that says the SpeedForce is limited to human beings, is there?), what might be the effect? Since we have established that Kryptonians are physically superior to humans, we might conclude that the SpeedForce would have a greater effect on them, or that they could absorb more of it, and thus run faster than a human exposed to the SpeedForce.
Therefore, my preliminary hypothesis would have to be that Superman can indeed outrun the Flash.