The ultimate truth regarding the sky, or any particular subject, would be the combination of all relative truths. The absolute truth cannot be expressed in language, in that language is relative. It cannot be expressed in terms that exclude any other terms, for by definition it is definitive, totally comprehensive. Absolute truth would have to be the combination of all ultimate truths. It would have to be, in other words, existence itself.
Relativity enters the picture in a big way.
The Bible Napoleon loved and the Bible revered by Albert Schweitzer are very different. We cannot know absolute truth until we are the Absolute. The Origin of Species is in no way definitive, even though it is regarded widely as the definitive word on evolution. The Origin is an interpretation of evolutionary process, an interpretation that has little scientific merit. Prior to that time, Christianity was just another persecuted cult.