Speed of Light is not Constant Always (again) (クリ)
Starlight is coming to a glass cube floating in outer space from the left and is leaving to the right. At the left and right ends of the glass, frequency of starlight is the same. Imagine that the glass is moving at various uniform speeds to the left and right. v of light on the left and right will not be the same, and so will λ (the formula v = fλ is viewed from perspective of the glass).
