As near as I can tell, Limitless is either a space-manipulation or gravity-manipulation technique, with blue creating an attracting force and red creating a repelling force. Both techniques create a sphere of light that has not been explained. However, the orb of light can be explained easily if the colors are reversed.

If light is moving away from you, it's wavelength is stretched out and it shifts red. If light is moving towards you, it's wavelength is compressed and it shifts blue. When Gojo creates an attracting force, light that escapes that force should be stretched out as it works against that force, creating a reddish tint. Likewise, when Gojo creates a repelling force, light should be accelerated away from that force, compressing its wavelength and shifting it blue.

However, what we see in the anime is the exact opposite. Can anyone think of an explanation as to why this might be, or should we just assume the colors were arbitrarily chosen as an intentional added effect of the technique?