The passages from Col & Eph are Revelation.  Christ (the Incarnate Word) holds all creation together. Any attempt to deflate that revealed truth when doing Scriptural exegesis can be validly called demythologization. "Demythologization" was a term used by Rudolf Bultmann to describe the means by which the essential truth of the gospel could be made acceptable to modern people.  Now the Word is the Lord of Science.  Advances in scientific understanding do not invalidate Revealed Truth.  If anything, they help us appreciate it more. The fact that the Word uses secondary causes in ordering creation does not negate or diminish the reality that He is the Author of creation.  I recommend the "Savior of Science" by Stanley Jaki, OSB who had doctorates in Physics & Theology as well as  "Fides et Ratio" by John Paul II. The passage in 1 Cor 15 about the sun, moon & stars is simply used analogically in the discussion of how our earthly bodies will differ from our glorified. Not a great analogy.