He's done the math. When the altitude reaches what we perceived as space energy usage reaches infinite, the theory of relativity thought the speed of light was the limiting factor, have you ever seen a picture of space being light? It doesn't happen. Space doesn't exist, it can't be reached. It is but an image created by our minds in an attempt to understand what we cannot visualize. Stars are just the creation of our minds to understand unfathomable non-existance. Why else do you think when you buddy looks at the stars and says "do you see that constellation that looks like Centaurus?" you can't see it, you see a few dots and play along that they see a mythical creature.

/Sarcasm... Just incase