Proof? The proof is in our memories. What color is the sun now? It is not gold anymore. Does it mean anything is the question.
And you are not just seeing things. The skys did used to be bluer AND we did not have as many sundogs, shakanas, etc.
Because: Some animals are more equal than other animals. -Animal Farm-
What the? > http://www.youtube.com/watch?v=6MTIwY3_-ks