I not only read the links, I read the original articles! People have learned how to manipulate the speed of light. Period.
I just walked into the room where Barry is working on his computer and asked him, "Can the speed of light be manipulated?"
Here is his answer: "Easily. Especially through the Casimir effect. As the plates get closeer, the speed of light goes faster between them because the ZPE is lessened by the elimination of the longer waves."
You are trying to deny the accuracy of a year, which is the earth's revolution around the sun by insisting the rotation of the earth on its axis is slightly variable. Sorry, Jovaro, that's two different things. The year is not measured by the days or months, but by the place it is in the solar system -- via the summer and winter soltices. The earth can slow or speed up in its turning on its axis, but the time it takes to go around the sun will be the same. Don't confuse the two things.