Hope you don't mind me entering my thoughts:
Gen 1:
1 In the beginning God created the heaven and the earth.
2 And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.
3 And God said, Let there be light: and there was light.
Christ Jesus is the "beginning", so, "In" the beginning... could mean within or inside the beginning.
Rev 1:8 I am Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty.
Moreover, the Light was not created, it was formed.
Isa 45:7 I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things.
All things were created "in" Christ Jesus.
The Sun, therefore, was created "in" Christ Jesus the Light of the world.
["in"=Gk. en — a primary preposition denoting (fixed) position (in place, time or state), and (by implication) instrumentality (medially or constructively), i.e. a relation of rest (intermediate between 1519 and 1537); TDNT - 2:537,233; prep]
KJV Col 1:17 And he is before all things, and in him all things consist.
NIV He is before all things, and in him all things hold together.
God is Light and Christ Jesus is the Light of the world (Gk. Kosmos).
1Joh 1:5 This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.
Joh 8:12 Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.
Christ Jesus, the beginning, is the Light of the world who was the first to come from God the Father of lights. Christ Jesus is the ending, which is to come for those who are yet to believe — the Almighty.
John 1:
1 In the beginning was the Word, and the Word was with God, and the Word was God.
2 The same was in the beginning with God.
3 All things were made by him; and without him was not any thing made that was made.
4 In him was life; and the life was the light of men.
5 And the light shineth in darkness; and the darkness comprehended it not.
6 There was a man sent from God, whose name was John.
7 The same came for a witness, to bear witness of the Light, that all men through him might believe.
8 He was not that Light, but was sent to bear witness of that Light.
9 That was the true Light, which lighteth every man that cometh into the world.
10 He was in the world, and the world was made by him, and the world knew him not.
11 He came unto his own, and his own received him not.
12 But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
13 Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
Blessings to all...