The reason for the Genesis creation stories (there are two of them) was not to give its readers a scientific explanation for how this planet came to exist. Instead, it was a rebuttal of a creation story which Moses' people had already learned during their stay in Egypt. Here is that story:
www.theologywebsite.com/etext/egypt/creation.shtml
Note that in this earlier story the gods and goddesses of Egypt created other gods and goddesses for the vast majority of the time, with mankind and all the other animals being created on the last day as almost an afterthought. It also had a five day timeline for the important aspects of creation, namely, the giving birth to deities. On the last day (the sixth day) we and all the other species of animals were created under their story.
There were over 40 different gods and goddesses in the egyptian pantheon, with each of them having a physical form. The sun and moon were to be seen as deities. The stars were to be seen as the garment worn by Queen Nut. The other gods and goddesses had the forms of animals, or combinations of two or more animals. Even the atmosphere was to be seen as a deity.
Moses methodically stripped all of these physical features of their divine attributes. In Genesis 1:1-2:3, he identified the sun, moon, and stars as merely objects in the heavens which gave them light, the animals around them as nothing more than other species of animals, the earth itself as nothing more than a surface which they lived on, the atmosphere as nothing more than the space that exists between the earth and the heavens, and the heavens as nothing more than that space which is above the planet. The only deity that was still to be accepted as such was one Person, himself invisible and totally beyond having his likeness painted or chiseled.
The second creation story (Genesis 2:4-25) was again a rebuttal of the egyptian creation story. In theirs mankind was merely another animal 'dumped' by the gods onto this planet. Moses set mankind apart. Alone of all the animals he could talk with God, and have God talk with him. He was given the task of naming all the other species of animals, a symbol of authority over those animals in that time period. He was given a special region where he could live comfortably (The Garden of Eden). And even his helpmate was created in a special manner, setting her apart from all other creatures.
He was also given the ability to go against God's orders and instead substitute his own desires. It was his acting on these desires which cost him the innocence which all other species have yet today. Alone of all the animals mankind has the knowledge that some actions are evil and other actions are good. When he attained this knowledge no one really knows. The story of the temptation by the serpent in the Garden of Eden is pure plagiarism, and it was famous enough so that the people to whom Genesis was written would have immediately recognized it. In egyptian mythology it was Ra the sun god who engaged Sebau the serpent-fiend in battle, defeated him, and then hacked off his hind legs and bound his front legs together, forcing him to crawl on the ground. Moses simply took that story and used it as a means of identifying the time when mankind lost his innocence. You can find this attested to in the first paragraph under the heading 'A Hymn to Ra' in The Egyptian Book of the Dead ( about five paragraphs from the beginning of the book):
www.africa.upenn.edu/Books/Papyrus_Ani.html